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* [PATCH] tty: serial: ip22zilog: Fix section mispatch warning
From: Thomas Bogendoerfer @ 2026-04-02 10:21 UTC (permalink / raw)
  To: Greg Kroah-Hartman, Jiri Slaby, Thomas Bogendoerfer, linux-kernel,
	linux-serial
  Cc: kernel test robot

ip22zilog_prepare() is now called by driver probe routine, so it
shouldn't be in the __init section any longer.

Fixes: 3fc36ae6abd2 ("tty: serial: ip22zilog: Use platform device for probing")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202604020945.c9jAvCPs-lkp@intel.com/
Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/tty/serial/ip22zilog.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/ip22zilog.c b/drivers/tty/serial/ip22zilog.c
index 6e19c6713849..a12101dc0554 100644
--- a/drivers/tty/serial/ip22zilog.c
+++ b/drivers/tty/serial/ip22zilog.c
@@ -1025,7 +1025,7 @@ static struct uart_driver ip22zilog_reg = {
 #endif
 };
 
-static void __init ip22zilog_prepare(struct uart_ip22zilog_port *up)
+static void ip22zilog_prepare(struct uart_ip22zilog_port *up)
 {
 	unsigned char sysrq_on = IS_ENABLED(CONFIG_SERIAL_IP22_ZILOG_CONSOLE);
 	int brg;
-- 
2.43.0


^ permalink raw reply related

* Re: [PATCH] tty: serial: ip22zilog: Fix section mispatch warning
From: Randy Dunlap @ 2026-04-02 18:35 UTC (permalink / raw)
  To: Thomas Bogendoerfer, Greg Kroah-Hartman, Jiri Slaby,
	Thomas Bogendoerfer, linux-kernel, linux-serial
  Cc: kernel test robot
In-Reply-To: <20260402102154.136620-1-tbogendoerfer@suse.de>



s/mispatch/mismatch/ in $Subject.

On 4/2/26 3:21 AM, Thomas Bogendoerfer wrote:
> ip22zilog_prepare() is now called by driver probe routine, so it
> shouldn't be in the __init section any longer.
> 
> Fixes: 3fc36ae6abd2 ("tty: serial: ip22zilog: Use platform device for probing")
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202604020945.c9jAvCPs-lkp@intel.com/
> Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>

Acked-by: Randy Dunlap <rdunlap@infradead.org>
Thanks.

> ---
>  drivers/tty/serial/ip22zilog.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/ip22zilog.c b/drivers/tty/serial/ip22zilog.c
> index 6e19c6713849..a12101dc0554 100644
> --- a/drivers/tty/serial/ip22zilog.c
> +++ b/drivers/tty/serial/ip22zilog.c
> @@ -1025,7 +1025,7 @@ static struct uart_driver ip22zilog_reg = {
>  #endif
>  };
>  
> -static void __init ip22zilog_prepare(struct uart_ip22zilog_port *up)
> +static void ip22zilog_prepare(struct uart_ip22zilog_port *up)
>  {
>  	unsigned char sysrq_on = IS_ENABLED(CONFIG_SERIAL_IP22_ZILOG_CONSOLE);
>  	int brg;

-- 
~Randy

^ permalink raw reply

* Re: [PATCH 3/3] power: sequencing: pcie-m2: Guard the helper functions making use of PCI bus notifier
From: kernel test robot @ 2026-04-02 22:56 UTC (permalink / raw)
  To: Manivannan Sadhasivam, brgl, robh
  Cc: llvm, oe-kbuild-all, linux-pci, linux-pm, linux-kernel,
	linux-serial, mani, Manivannan Sadhasivam, kernel test robot
In-Reply-To: <20260401070735.107162-4-manivannan.sadhasivam@oss.qualcomm.com>

Hi Manivannan,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linux-next/master]
[also build test WARNING on linus/master v6.16-rc1]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Manivannan-Sadhasivam/serdev-Add-missing-stubs-for-serdev-APIs-when-CONFIG_SERIAL_DEV_BUS-is-not-selected/20260402-225703
base:   linux-next/master
patch link:    https://lore.kernel.org/r/20260401070735.107162-4-manivannan.sadhasivam%40oss.qualcomm.com
patch subject: [PATCH 3/3] power: sequencing: pcie-m2: Guard the helper functions making use of PCI bus notifier
config: x86_64-kexec (https://download.01.org/0day-ci/archive/20260403/202604030008.5exLAPFm-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260403/202604030008.5exLAPFm-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202604030008.5exLAPFm-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from drivers/tty/tty_port.c:20:
>> include/linux/serdev.h:268:83: warning: omitting the parameter name in a function definition is a C23 extension [-Wc23-extensions]
     268 | static inline struct serdev_device *serdev_device_alloc(struct serdev_controller *)
         |                                                                                   ^
   include/linux/serdev.h:272:59: warning: omitting the parameter name in a function definition is a C23 extension [-Wc23-extensions]
     272 | static inline int serdev_device_add(struct serdev_device *)
         |                                                           ^
   include/linux/serdev.h:276:63: warning: omitting the parameter name in a function definition is a C23 extension [-Wc23-extensions]
     276 | static inline void serdev_device_remove(struct serdev_device *) {}
         |                                                               ^
   include/linux/serdev.h:284:67: warning: omitting the parameter name in a function definition is a C23 extension [-Wc23-extensions]
     284 | static inline int serdev_controller_add(struct serdev_controller *)
         |                                                                   ^
   include/linux/serdev.h:288:71: warning: omitting the parameter name in a function definition is a C23 extension [-Wc23-extensions]
     288 | static inline void serdev_controller_remove(struct serdev_controller *) {}
         |                                                                       ^
   5 warnings generated.


vim +268 include/linux/serdev.h

   267	
 > 268	static inline struct serdev_device *serdev_device_alloc(struct serdev_controller *)
   269	{
   270		return NULL;
   271	}
   272	static inline int serdev_device_add(struct serdev_device *)
   273	{
   274		return -ENODEV;
   275	}
   276	static inline void serdev_device_remove(struct serdev_device *) {}
   277	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

^ permalink raw reply

* [PATCH v3 0/9] driver core: Fix some race conditions
From: Douglas Anderson @ 2026-04-03  0:49 UTC (permalink / raw)
  To: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
	Alan Stern
  Cc: Robin Murphy, Leon Romanovsky, Paul Burton, Saravana Kannan,
	Alexander Lobakin, Eric Dumazet, Toshi Kani, Christoph Hellwig,
	Alexey Kardashevskiy, Johan Hovold, Douglas Anderson,
	Andrew Morton, Frank.Li, Jason Gunthorpe, alex, alexander.stein,
	andre.przywara, andrew, andrew, andriy.shevchenko, aou, ardb,
	astewart, bhelgaas, brgl, broonie, catalin.marinas, chleroy,
	davem, david, devicetree, dmaengine, driver-core, gbatra,
	gregory.clement, hkallweit1, iommu, jirislaby, joel, joro, kees,
	kevin.brodsky, kuba, lenb, lgirdwood, linux-acpi,
	linux-arm-kernel, linux-aspeed, linux-cxl, linux-kernel,
	linux-mips, linux-mm, linux-pci, linux-riscv, linux-serial,
	linux-snps-arc, linux-usb, linux, linuxppc-dev, m.szyprowski,
	maddy, mani, maz, miko.lenczewski, mpe, netdev, npiggin,
	osalvador, oupton, pabeni, palmer, peter.ujfalusi, peterz, pjw,
	robh, sebastian.hesselbarth, tglx, tsbogend, vgupta, vkoul, will,
	willy, yangyicong, yeoreum.yun

The main goal of this series is to fix the observed bug talked about
in the first patch ("driver core: Don't let a device probe until it's
ready"). That patch fixes a problem that has been observed in the real
world and could land even if the rest of the patches are found
unacceptable or need to be spun.

That said, during patch review Danilo correctly pointed out that many
of the bitfield accesses in "struct device" are unsafe. I added a
bunch of patches in the series to address each one.

Danilo said he's most worried about "can_match", so I put that one
first. After that, I tried to transition bitfields to flags in reverse
order to when the bitfield was added.

Even if transitioning from bitfields to flags isn't truly needed for
correctness, it seems silly (and wasteful of space in struct device)
to have some in bitfields and some as flags. Thus I didn't spend time
for each bitfield showing that it's truly needed for correctness.

Transition was done semi manually. Presumably someone skilled at
coccinelle could do a better job, but I just used sed in a heavy-
handed manner and then reviewed/fixed the results, undoing anything my
script got wrong. My terrible/ugly script was:

var=can_match
caps="${var^^}"
for f in $(git grep -l "[>\.]${var}[^1-9_a-zA-Z\[]"); do
  echo $f
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = true/set_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = true/set_bit(DEV_FLAG_${caps}, \&\\1.flags)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = false/clear_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = false/clear_bit(DEV_FLAG_${caps}, \&\\1.flags)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = \([^;]*\)/assign_bit(DEV_FLAG_${caps}, \&\\1->flags, \\2)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = \([^;]*\)/assign_bit(DEV_FLAG_${caps}, \&\\1.flags, \\2)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var}\([^1-9_a-zA-Z\[]\)/test_bit(DEV_FLAG_${caps}, \&\\1->flags)\\2/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var}\([^1-9_a-zA-Z\[]\)/test_bit(DEV_FLAG_${caps}, \&\\1.flags)\\2/" "$f"
done

NOTE: one potentially "controversial" choice I made in some patches
was to always reserve a flag ID even if a flag is only used under
certain CONFIG_ settings. This is a change from how things were
before. Keeping the numbering consistent and allowing easy
compile-testing of both CONFIG settings seemed worth it, especially
since it won't take up any extra space until we've added a lot more
flags.

I only marked the first patch as a "Fix" since it is the only one
fixing observed problems. Other patches could be considered fixes too
if folks want.

I tested the first patch in the series backported to kernel 6.6 on the
Pixel phone that was experiencing the race. I added extra printouts to
make sure that the problem was hitting / addressed. The rest of the
patches are tested with allmodconfig with arm32, arm64, ppc, and
x86. I boot tested on an arm64 Chromebook running mainline.

Changes in v3:
- Use a new "flags" bitfield
- Add missing \n in probe error message

Changes in v2:
- Instead of adjusting the ordering, use "ready_to_probe" flag

Douglas Anderson (9):
  driver core: Don't let a device probe until it's ready
  driver core: Replace dev->can_match with DEV_FLAG_CAN_MATCH
  driver core: Replace dev->dma_iommu with DEV_FLAG_DMA_IOMMU
  driver core: Replace dev->dma_skip_sync with DEV_FLAG_DMA_SKIP_SYNC
  driver core: Replace dev->dma_ops_bypass with DEV_FLAG_DMA_OPS_BYPASS
  driver core: Replace dev->state_synced with DEV_FLAG_STATE_SYNCED
  driver core: Replace dev->dma_coherent with DEV_FLAG_DMA_COHERENT
  driver core: Replace dev->of_node_reused with DEV_FLAG_OF_NODE_REUSED
  driver core: Replace dev->offline + ->offline_disabled with DEV_FLAGs

 arch/arc/mm/dma.c                             |  4 +-
 arch/arm/mach-highbank/highbank.c             |  2 +-
 arch/arm/mach-mvebu/coherency.c               |  2 +-
 arch/arm/mm/dma-mapping-nommu.c               |  4 +-
 arch/arm/mm/dma-mapping.c                     | 30 +++----
 arch/arm64/kernel/cpufeature.c                |  2 +-
 arch/arm64/mm/dma-mapping.c                   |  2 +-
 arch/mips/mm/dma-noncoherent.c                |  2 +-
 arch/powerpc/kernel/dma-iommu.c               |  8 +-
 .../platforms/pseries/hotplug-memory.c        |  4 +-
 arch/riscv/mm/dma-noncoherent.c               |  2 +-
 drivers/acpi/scan.c                           |  3 +-
 drivers/base/core.c                           | 55 +++++++-----
 drivers/base/cpu.c                            |  4 +-
 drivers/base/dd.c                             | 28 +++++--
 drivers/base/memory.c                         |  2 +-
 drivers/base/pinctrl.c                        |  2 +-
 drivers/base/platform.c                       |  2 +-
 drivers/dma/ti/k3-udma-glue.c                 |  6 +-
 drivers/dma/ti/k3-udma.c                      |  6 +-
 drivers/iommu/dma-iommu.c                     |  9 +-
 drivers/iommu/iommu.c                         |  5 +-
 drivers/net/pcs/pcs-xpcs-plat.c               |  2 +-
 drivers/of/device.c                           |  6 +-
 drivers/pci/of.c                              |  2 +-
 drivers/pci/pwrctrl/core.c                    |  2 +-
 drivers/regulator/bq257xx-regulator.c         |  2 +-
 drivers/regulator/rk808-regulator.c           |  2 +-
 drivers/tty/serial/serial_base_bus.c          |  2 +-
 drivers/usb/gadget/udc/aspeed-vhub/dev.c      |  2 +-
 include/linux/device.h                        | 83 ++++++++++---------
 include/linux/dma-map-ops.h                   |  6 +-
 include/linux/dma-mapping.h                   |  2 +-
 include/linux/iommu-dma.h                     |  4 +-
 kernel/cpu.c                                  |  4 +-
 kernel/dma/mapping.c                          | 16 ++--
 mm/hmm.c                                      |  2 +-
 37 files changed, 178 insertions(+), 143 deletions(-)

-- 
2.53.0.1213.gd9a14994de-goog


^ permalink raw reply

* [PATCH v3 8/9] driver core: Replace dev->of_node_reused with DEV_FLAG_OF_NODE_REUSED
From: Douglas Anderson @ 2026-04-03  0:49 UTC (permalink / raw)
  To: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
	Alan Stern
  Cc: Robin Murphy, Leon Romanovsky, Paul Burton, Saravana Kannan,
	Alexander Lobakin, Eric Dumazet, Toshi Kani, Christoph Hellwig,
	Alexey Kardashevskiy, Johan Hovold, Douglas Anderson,
	alexander.stein, andrew, andrew, andriy.shevchenko, astewart,
	bhelgaas, brgl, broonie, davem, devicetree, driver-core,
	hkallweit1, jirislaby, joel, kees, kuba, lgirdwood,
	linux-arm-kernel, linux-aspeed, linux-kernel, linux-pci,
	linux-serial, linux-usb, linux, mani, netdev, pabeni, robh
In-Reply-To: <20260403005005.30424-1-dianders@chromium.org>

In C, bitfields are not necessarily safe to modify from multiple
threads without locking. Switch "of_node_reused" over to the "flags"
field so modifications are safe.

Cc: Johan Hovold <johan@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Not fixing any known bugs; problem is theoretical and found by code
inspection. Change is done somewhat manually and only lightly tested
(mostly compile-time tested).

Changes in v3:
- New

 drivers/base/core.c                      | 2 +-
 drivers/base/pinctrl.c                   | 2 +-
 drivers/base/platform.c                  | 2 +-
 drivers/net/pcs/pcs-xpcs-plat.c          | 2 +-
 drivers/of/device.c                      | 6 +++---
 drivers/pci/of.c                         | 2 +-
 drivers/pci/pwrctrl/core.c               | 2 +-
 drivers/regulator/bq257xx-regulator.c    | 2 +-
 drivers/regulator/rk808-regulator.c      | 2 +-
 drivers/tty/serial/serial_base_bus.c     | 2 +-
 drivers/usb/gadget/udc/aspeed-vhub/dev.c | 2 +-
 include/linux/device.h                   | 6 +++---
 12 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 00005777c21f..a87bd40499b6 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -5282,7 +5282,7 @@ void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
 {
 	of_node_put(dev->of_node);
 	dev->of_node = of_node_get(dev2->of_node);
-	dev->of_node_reused = true;
+	set_bit(DEV_FLAG_OF_NODE_REUSED, &dev->flags);
 }
 EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
 
diff --git a/drivers/base/pinctrl.c b/drivers/base/pinctrl.c
index 6e250272c843..62c228c75d50 100644
--- a/drivers/base/pinctrl.c
+++ b/drivers/base/pinctrl.c
@@ -24,7 +24,7 @@ int pinctrl_bind_pins(struct device *dev)
 {
 	int ret;
 
-	if (dev->of_node_reused)
+	if (test_bit(DEV_FLAG_OF_NODE_REUSED, &dev->flags))
 		return 0;
 
 	dev->pins = devm_kzalloc(dev, sizeof(*(dev->pins)), GFP_KERNEL);
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index d44591d52e36..5128ff7e5e78 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -856,7 +856,7 @@ struct platform_device *platform_device_register_full(
 	pdev->dev.parent = pdevinfo->parent;
 	pdev->dev.fwnode = pdevinfo->fwnode;
 	pdev->dev.of_node = of_node_get(to_of_node(pdev->dev.fwnode));
-	pdev->dev.of_node_reused = pdevinfo->of_node_reused;
+	assign_bit(DEV_FLAG_OF_NODE_REUSED, &pdev->dev.flags, pdevinfo->of_node_reused);
 
 	if (pdevinfo->dma_mask) {
 		pdev->platform_dma_mask = pdevinfo->dma_mask;
diff --git a/drivers/net/pcs/pcs-xpcs-plat.c b/drivers/net/pcs/pcs-xpcs-plat.c
index b8c48f9effbf..c2722d8bd98a 100644
--- a/drivers/net/pcs/pcs-xpcs-plat.c
+++ b/drivers/net/pcs/pcs-xpcs-plat.c
@@ -349,7 +349,7 @@ static int xpcs_plat_init_dev(struct dw_xpcs_plat *pxpcs)
 	 * up later. Make sure DD-core is aware of the OF-node being re-used.
 	 */
 	device_set_node(&mdiodev->dev, fwnode_handle_get(dev_fwnode(dev)));
-	mdiodev->dev.of_node_reused = true;
+	set_bit(DEV_FLAG_OF_NODE_REUSED, &mdiodev->dev.flags);
 
 	/* Pass the data further so the DW XPCS driver core could use it */
 	mdiodev->dev.platform_data = (void *)device_get_match_data(dev);
diff --git a/drivers/of/device.c b/drivers/of/device.c
index f7e75e527667..fd77295a8c0f 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -26,7 +26,7 @@
 const struct of_device_id *of_match_device(const struct of_device_id *matches,
 					   const struct device *dev)
 {
-	if (!matches || !dev->of_node || dev->of_node_reused)
+	if (!matches || !dev->of_node || test_bit(DEV_FLAG_OF_NODE_REUSED, &dev->flags))
 		return NULL;
 	return of_match_node(matches, dev->of_node);
 }
@@ -192,7 +192,7 @@ ssize_t of_device_modalias(struct device *dev, char *str, ssize_t len)
 {
 	ssize_t sl;
 
-	if (!dev || !dev->of_node || dev->of_node_reused)
+	if (!dev || !dev->of_node || test_bit(DEV_FLAG_OF_NODE_REUSED, &dev->flags))
 		return -ENODEV;
 
 	sl = of_modalias(dev->of_node, str, len - 2);
@@ -254,7 +254,7 @@ int of_device_uevent_modalias(const struct device *dev, struct kobj_uevent_env *
 {
 	int sl;
 
-	if ((!dev) || (!dev->of_node) || dev->of_node_reused)
+	if ((!dev) || (!dev->of_node) || test_bit(DEV_FLAG_OF_NODE_REUSED, &dev->flags))
 		return -ENODEV;
 
 	/* Devicetree modalias is tricky, we add it in 2 steps */
diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index 9f8eb5df279e..197b60c5a660 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -38,7 +38,7 @@ int pci_set_of_node(struct pci_dev *dev)
 	struct device *pdev __free(put_device) =
 		bus_find_device_by_of_node(&platform_bus_type, node);
 	if (pdev)
-		dev->bus->dev.of_node_reused = true;
+		set_bit(DEV_FLAG_OF_NODE_REUSED, &dev->bus->dev.flags);
 
 	device_set_node(&dev->dev, of_fwnode_handle(no_free_ptr(node)));
 	return 0;
diff --git a/drivers/pci/pwrctrl/core.c b/drivers/pci/pwrctrl/core.c
index 7754baed67f2..cfbe9b615b88 100644
--- a/drivers/pci/pwrctrl/core.c
+++ b/drivers/pci/pwrctrl/core.c
@@ -39,7 +39,7 @@ static int pci_pwrctrl_notify(struct notifier_block *nb, unsigned long action,
 		 * If we got here then the PCI device is the second after the
 		 * power control platform device. Mark its OF node as reused.
 		 */
-		dev->of_node_reused = true;
+		set_bit(DEV_FLAG_OF_NODE_REUSED, &dev->flags);
 		break;
 	}
 
diff --git a/drivers/regulator/bq257xx-regulator.c b/drivers/regulator/bq257xx-regulator.c
index dab8f1ab4450..01d3139e1d87 100644
--- a/drivers/regulator/bq257xx-regulator.c
+++ b/drivers/regulator/bq257xx-regulator.c
@@ -143,7 +143,7 @@ static int bq257xx_regulator_probe(struct platform_device *pdev)
 	struct regulator_config cfg = {};
 
 	pdev->dev.of_node = pdev->dev.parent->of_node;
-	pdev->dev.of_node_reused = true;
+	set_bit(DEV_FLAG_OF_NODE_REUSED, &pdev->dev.flags);
 
 	pdata = devm_kzalloc(&pdev->dev, sizeof(struct bq257xx_reg_data), GFP_KERNEL);
 	if (!pdata)
diff --git a/drivers/regulator/rk808-regulator.c b/drivers/regulator/rk808-regulator.c
index e66408f23bb6..375ea7861134 100644
--- a/drivers/regulator/rk808-regulator.c
+++ b/drivers/regulator/rk808-regulator.c
@@ -2115,7 +2115,7 @@ static int rk808_regulator_probe(struct platform_device *pdev)
 	int ret, i, nregulators;
 
 	pdev->dev.of_node = pdev->dev.parent->of_node;
-	pdev->dev.of_node_reused = true;
+	set_bit(DEV_FLAG_OF_NODE_REUSED, &pdev->dev.flags);
 
 	regmap = dev_get_regmap(pdev->dev.parent, NULL);
 	if (!regmap)
diff --git a/drivers/tty/serial/serial_base_bus.c b/drivers/tty/serial/serial_base_bus.c
index a12935f6b992..86c6003bbebb 100644
--- a/drivers/tty/serial/serial_base_bus.c
+++ b/drivers/tty/serial/serial_base_bus.c
@@ -74,7 +74,7 @@ static int serial_base_device_init(struct uart_port *port,
 	dev->parent = parent_dev;
 	dev->bus = &serial_base_bus_type;
 	dev->release = release;
-	dev->of_node_reused = true;
+	set_bit(DEV_FLAG_OF_NODE_REUSED, &dev->flags);
 
 	device_set_node(dev, fwnode_handle_get(dev_fwnode(parent_dev)));
 
diff --git a/drivers/usb/gadget/udc/aspeed-vhub/dev.c b/drivers/usb/gadget/udc/aspeed-vhub/dev.c
index 2ecd049dacc2..57048e3aa6bb 100644
--- a/drivers/usb/gadget/udc/aspeed-vhub/dev.c
+++ b/drivers/usb/gadget/udc/aspeed-vhub/dev.c
@@ -593,7 +593,7 @@ int ast_vhub_init_dev(struct ast_vhub *vhub, unsigned int idx)
 		d->gadget.max_speed = USB_SPEED_HIGH;
 	d->gadget.speed = USB_SPEED_UNKNOWN;
 	d->gadget.dev.of_node = vhub->pdev->dev.of_node;
-	d->gadget.dev.of_node_reused = true;
+	set_bit(DEV_FLAG_OF_NODE_REUSED, &d->gadget.dev.flags);
 
 	rc = usb_add_gadget_udc(d->port_dev, &d->gadget);
 	if (rc != 0)
diff --git a/include/linux/device.h b/include/linux/device.h
index c2a6dba7a036..f6ca067bacca 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -482,6 +482,8 @@ struct device_physical_location {
  *		driver/bus sync_state() callback.
  * @DEV_FLAG_DMA_COHERENT: This particular device is dma coherent, even if the
  *		architecture supports non-coherent devices.
+ * @DEV_FLAG_OF_NODE_REUSED: Set if the device-tree node is shared with an
+ *		ancestor device.
  */
 enum struct_device_flags {
 	DEV_FLAG_READY_TO_PROBE,
@@ -491,6 +493,7 @@ enum struct_device_flags {
 	DEV_FLAG_DMA_OPS_BYPASS,
 	DEV_FLAG_STATE_SYNCED,
 	DEV_FLAG_DMA_COHERENT,
+	DEV_FLAG_OF_NODE_REUSED,
 };
 
 /**
@@ -570,8 +573,6 @@ enum struct_device_flags {
  *
  * @offline_disabled: If set, the device is permanently online.
  * @offline:	Set after successful invocation of bus type's .offline().
- * @of_node_reused: Set if the device-tree node is shared with an ancestor
- *              device.
  * @flags:	DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
  *
  * At the lowest level, every device in a Linux system is represented by an
@@ -678,7 +679,6 @@ struct device {
 
 	bool			offline_disabled:1;
 	bool			offline:1;
-	bool			of_node_reused:1;
 
 	unsigned long		flags;
 };
-- 
2.53.0.1213.gd9a14994de-goog


^ permalink raw reply related

* [tty:tty-testing] BUILD SUCCESS a1a81aef99e853dec84241d701fbf587d713eb5b
From: kernel test robot @ 2026-04-03  3:25 UTC (permalink / raw)
  To: Greg Kroah-Hartman; +Cc: linux-serial

tree/branch: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-testing
branch HEAD: a1a81aef99e853dec84241d701fbf587d713eb5b  tty: serial: ip22zilog: Fix section mispatch warning

elapsed time: 735m

configs tested: 170
configs skipped: 2

The following configs have been built successfully.
More configs may be tested in the coming days.

tested configs:
alpha                             allnoconfig    gcc-15.2.0
alpha                            allyesconfig    gcc-15.2.0
alpha                               defconfig    gcc-15.2.0
arc                              allmodconfig    clang-16
arc                               allnoconfig    gcc-15.2.0
arc                              allyesconfig    clang-23
arc                                 defconfig    gcc-15.2.0
arc                   randconfig-001-20260403    gcc-10.5.0
arc                   randconfig-002-20260403    gcc-10.5.0
arm                               allnoconfig    gcc-15.2.0
arm                              allyesconfig    clang-16
arm                                 defconfig    gcc-15.2.0
arm                         orion5x_defconfig    clang-23
arm                   randconfig-001-20260403    gcc-10.5.0
arm                   randconfig-002-20260403    gcc-10.5.0
arm                   randconfig-003-20260403    gcc-10.5.0
arm                   randconfig-004-20260403    gcc-10.5.0
arm64                            allmodconfig    clang-23
arm64                             allnoconfig    gcc-15.2.0
arm64                               defconfig    gcc-15.2.0
arm64                 randconfig-001-20260403    gcc-13.4.0
arm64                 randconfig-002-20260403    gcc-13.4.0
arm64                 randconfig-003-20260403    gcc-13.4.0
arm64                 randconfig-004-20260403    gcc-13.4.0
csky                             allmodconfig    gcc-15.2.0
csky                              allnoconfig    gcc-15.2.0
csky                                defconfig    gcc-15.2.0
csky                  randconfig-001-20260403    gcc-13.4.0
csky                  randconfig-002-20260403    gcc-13.4.0
hexagon                          allmodconfig    gcc-15.2.0
hexagon                           allnoconfig    gcc-15.2.0
hexagon                             defconfig    gcc-15.2.0
hexagon               randconfig-001-20260403    clang-23
hexagon               randconfig-002-20260403    clang-23
i386                             allmodconfig    clang-20
i386                              allnoconfig    gcc-15.2.0
i386                             allyesconfig    clang-20
i386        buildonly-randconfig-001-20260403    gcc-14
i386        buildonly-randconfig-002-20260403    gcc-14
i386        buildonly-randconfig-003-20260403    gcc-14
i386        buildonly-randconfig-004-20260403    gcc-14
i386        buildonly-randconfig-005-20260403    gcc-14
i386        buildonly-randconfig-006-20260403    gcc-14
i386                                defconfig    gcc-15.2.0
i386                  randconfig-001-20260403    gcc-14
i386                  randconfig-002-20260403    gcc-14
i386                  randconfig-003-20260403    gcc-14
i386                  randconfig-004-20260403    gcc-14
i386                  randconfig-005-20260403    gcc-14
i386                  randconfig-006-20260403    gcc-14
i386                  randconfig-007-20260403    gcc-14
i386                  randconfig-011-20260403    clang-20
i386                  randconfig-012-20260403    clang-20
i386                  randconfig-013-20260403    clang-20
i386                  randconfig-014-20260403    clang-20
i386                  randconfig-015-20260403    clang-20
i386                  randconfig-016-20260403    clang-20
i386                  randconfig-017-20260403    clang-20
loongarch                        allmodconfig    clang-23
loongarch                         allnoconfig    gcc-15.2.0
loongarch                           defconfig    clang-19
loongarch             randconfig-001-20260403    clang-23
loongarch             randconfig-002-20260403    clang-23
m68k                             allmodconfig    gcc-15.2.0
m68k                              allnoconfig    gcc-15.2.0
m68k                             allyesconfig    clang-16
m68k                                defconfig    clang-19
microblaze                        allnoconfig    gcc-15.2.0
microblaze                       allyesconfig    gcc-15.2.0
microblaze                          defconfig    clang-19
mips                             allmodconfig    gcc-15.2.0
mips                              allnoconfig    gcc-15.2.0
mips                             allyesconfig    gcc-15.2.0
nios2                            allmodconfig    clang-23
nios2                             allnoconfig    clang-23
nios2                               defconfig    clang-19
nios2                 randconfig-001-20260403    clang-23
nios2                 randconfig-002-20260403    clang-23
openrisc                         allmodconfig    clang-23
openrisc                          allnoconfig    clang-23
openrisc                            defconfig    gcc-15.2.0
parisc                           allmodconfig    gcc-15.2.0
parisc                            allnoconfig    clang-23
parisc                           allyesconfig    clang-19
parisc                              defconfig    gcc-15.2.0
parisc                randconfig-001-20260403    gcc-10.5.0
parisc                randconfig-002-20260403    gcc-10.5.0
parisc64                            defconfig    clang-19
powerpc                          allmodconfig    gcc-15.2.0
powerpc                           allnoconfig    clang-23
powerpc               randconfig-001-20260403    gcc-10.5.0
powerpc               randconfig-002-20260403    gcc-10.5.0
powerpc                     tqm5200_defconfig    gcc-15.2.0
powerpc64             randconfig-001-20260403    gcc-10.5.0
powerpc64             randconfig-002-20260403    gcc-10.5.0
riscv                            allmodconfig    clang-23
riscv                             allnoconfig    clang-23
riscv                            allyesconfig    clang-16
riscv                               defconfig    gcc-15.2.0
riscv                 randconfig-001-20260403    clang-23
riscv                 randconfig-002-20260403    clang-23
s390                             allmodconfig    clang-19
s390                              allnoconfig    clang-23
s390                             allyesconfig    gcc-15.2.0
s390                                defconfig    gcc-15.2.0
s390                  randconfig-001-20260403    clang-23
s390                  randconfig-002-20260403    clang-23
sh                               allmodconfig    gcc-15.2.0
sh                                allnoconfig    clang-23
sh                               allyesconfig    clang-19
sh                                  defconfig    gcc-14
sh                     magicpanelr2_defconfig    gcc-15.2.0
sh                    randconfig-001-20260403    clang-23
sh                    randconfig-002-20260403    clang-23
sparc                             allnoconfig    clang-23
sparc                               defconfig    gcc-15.2.0
sparc                 randconfig-001-20260403    clang-20
sparc                 randconfig-002-20260403    clang-20
sparc64                          allmodconfig    clang-23
sparc64                             defconfig    gcc-14
sparc64               randconfig-001-20260403    clang-20
sparc64               randconfig-002-20260403    clang-20
um                               allmodconfig    clang-19
um                                allnoconfig    clang-23
um                               allyesconfig    gcc-15.2.0
um                                  defconfig    gcc-14
um                             i386_defconfig    gcc-14
um                    randconfig-001-20260403    clang-20
um                    randconfig-002-20260403    clang-20
um                           x86_64_defconfig    gcc-14
x86_64                           allmodconfig    clang-20
x86_64                            allnoconfig    clang-23
x86_64                           allyesconfig    clang-20
x86_64      buildonly-randconfig-001-20260403    clang-20
x86_64      buildonly-randconfig-002-20260403    clang-20
x86_64      buildonly-randconfig-003-20260403    clang-20
x86_64      buildonly-randconfig-004-20260403    clang-20
x86_64      buildonly-randconfig-005-20260403    clang-20
x86_64      buildonly-randconfig-006-20260403    clang-20
x86_64                              defconfig    gcc-14
x86_64                                  kexec    clang-20
x86_64                randconfig-001-20260403    clang-20
x86_64                randconfig-002-20260403    clang-20
x86_64                randconfig-003-20260403    clang-20
x86_64                randconfig-004-20260403    clang-20
x86_64                randconfig-005-20260403    clang-20
x86_64                randconfig-006-20260403    clang-20
x86_64                randconfig-011-20260403    gcc-14
x86_64                randconfig-012-20260403    gcc-14
x86_64                randconfig-013-20260403    gcc-14
x86_64                randconfig-014-20260403    gcc-14
x86_64                randconfig-015-20260403    gcc-14
x86_64                randconfig-016-20260403    gcc-14
x86_64                randconfig-071-20260403    gcc-14
x86_64                randconfig-072-20260403    gcc-14
x86_64                randconfig-073-20260403    gcc-14
x86_64                randconfig-074-20260403    gcc-14
x86_64                randconfig-075-20260403    gcc-14
x86_64                randconfig-076-20260403    gcc-14
x86_64                               rhel-9.4    clang-20
x86_64                           rhel-9.4-bpf    gcc-14
x86_64                          rhel-9.4-func    clang-20
x86_64                    rhel-9.4-kselftests    clang-20
x86_64                         rhel-9.4-kunit    gcc-14
x86_64                           rhel-9.4-ltp    gcc-14
x86_64                          rhel-9.4-rust    clang-20
xtensa                            allnoconfig    clang-23
xtensa                           allyesconfig    clang-23
xtensa                randconfig-001-20260403    clang-20
xtensa                randconfig-002-20260403    clang-20

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

^ permalink raw reply

* Re: [PATCH v3 8/9] driver core: Replace dev->of_node_reused with DEV_FLAG_OF_NODE_REUSED
From: Mark Brown @ 2026-04-03 11:56 UTC (permalink / raw)
  To: Douglas Anderson
  Cc: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
	Alan Stern, Robin Murphy, Leon Romanovsky, Paul Burton,
	Saravana Kannan, Alexander Lobakin, Eric Dumazet, Toshi Kani,
	Christoph Hellwig, Alexey Kardashevskiy, Johan Hovold,
	alexander.stein, andrew, andrew, andriy.shevchenko, astewart,
	bhelgaas, brgl, davem, devicetree, driver-core, hkallweit1,
	jirislaby, joel, kees, kuba, lgirdwood, linux-arm-kernel,
	linux-aspeed, linux-kernel, linux-pci, linux-serial, linux-usb,
	linux, mani, netdev, pabeni, robh
In-Reply-To: <20260402174925.v3.8.I806b8636cd3724f6cd1f5e199318ab8694472d90@changeid>

[-- Attachment #1: Type: text/plain, Size: 282 bytes --]

On Thu, Apr 02, 2026 at 05:49:54PM -0700, Douglas Anderson wrote:
> In C, bitfields are not necessarily safe to modify from multiple
> threads without locking. Switch "of_node_reused" over to the "flags"
> field so modifications are safe.

Acked-by: Mark Brown <broonie@kernel.org>

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

^ permalink raw reply

* Re: [moderation] KCSAN: data-race in n_tty_flush_buffer / n_tty_lookahead_flow_ctrl (9)
From: syzbot @ 2026-04-03 13:20 UTC (permalink / raw)
  To: andy.shevchenko, gregkh, ilpo.jarvinen, jirislaby, linux-kernel,
	linux-serial, osama.abdelkader, syzkaller-upstream-moderation
In-Reply-To: <6985ea97.050a0220.3b3015.003e.GAE@google.com>

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.

^ permalink raw reply

* [PATCH v4 0/9] driver core: Fix some race conditions
From: Douglas Anderson @ 2026-04-04  0:04 UTC (permalink / raw)
  To: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
	Alan Stern
  Cc: Saravana Kannan, Christoph Hellwig, Eric Dumazet, Johan Hovold,
	Leon Romanovsky, Alexander Lobakin, Alexey Kardashevskiy,
	Robin Murphy, Douglas Anderson, Andrew Morton, Frank.Li,
	Jason Gunthorpe, alex, alexander.stein, andre.przywara, andrew,
	andrew, andriy.shevchenko, aou, ardb, bhelgaas, brgl, broonie,
	catalin.marinas, chleroy, davem, david, devicetree, dmaengine,
	driver-core, gbatra, gregory.clement, hkallweit1, iommu,
	jirislaby, joel, joro, kees, kevin.brodsky, kuba, lenb, lgirdwood,
	linux-acpi, linux-arm-kernel, linux-aspeed, linux-cxl,
	linux-kernel, linux-mips, linux-mm, linux-pci, linux-riscv,
	linux-serial, linux-snps-arc, linux-usb, linux, linuxppc-dev,
	m.szyprowski, maddy, mani, maz, miko.lenczewski, mpe, netdev,
	npiggin, osalvador, oupton, pabeni, palmer, peter.ujfalusi,
	peterz, pjw, robh, sebastian.hesselbarth, tglx, tsbogend, vgupta,
	vkoul, will, willy, yangyicong, yeoreum.yun

The main goal of this series is to fix the observed bug talked about
in the first patch ("driver core: Don't let a device probe until it's
ready"). That patch fixes a problem that has been observed in the real
world and could land even if the rest of the patches are found
unacceptable or need to be spun.

That said, during patch review Danilo correctly pointed out that many
of the bitfield accesses in "struct device" are unsafe. I added a
bunch of patches in the series to address each one.

Danilo said he's most worried about "can_match", so I put that one
first. After that, I tried to transition bitfields to flags in reverse
order to when the bitfield was added.

Even if transitioning from bitfields to flags isn't truly needed for
correctness, it seems silly (and wasteful of space in struct device)
to have some in bitfields and some as flags. Thus I didn't spend time
for each bitfield showing that it's truly needed for correctness.

Transition was done semi manually. Presumably someone skilled at
coccinelle could do a better job, but I just used sed in a heavy-
handed manner and then reviewed/fixed the results, undoing anything my
script got wrong. My terrible/ugly script was:

var=can_match
caps="${var^^}"
for f in $(git grep -l "[>\.]${var}[^1-9_a-zA-Z\[]"); do
  echo $f
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = true/set_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = true/dev_set_${caps}(\&\\1)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = false/clear_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = false/dev_clear_${caps}(\&\\1)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = \([^;]*\)/assign_bit(DEV_FLAG_${caps}, \&\\1->flags, \\2)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = \([^;]*\)/dev_assign_${caps}(\&\\1, \\2)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var}\([^1-9_a-zA-Z\[]\)/test_bit(DEV_FLAG_${caps}, \&\\1->flags)\\2/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var}\([^1-9_a-zA-Z\[]\)/dev_${caps}(\&\\1)\\2/" "$f"
done

From v3 to v4, I transitioned to accessor functions with another ugly
sed script. I had git format the old patches, then transformed them
with:

for f in *.patch; do
  echo $f
  sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_set_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_set_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_clear_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_clear_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
  sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
done

...and then did a few manual touchups for spacing.

NOTE: one potentially "controversial" choice I made in some patches
was to always reserve a flag ID even if a flag is only used under
certain CONFIG_ settings. This is a change from how things were
before. Keeping the numbering consistent and allowing easy
compile-testing of both CONFIG settings seemed worth it, especially
since it won't take up any extra space until we've added a lot more
flags.

I only marked the first patch as a "Fix" since it is the only one
fixing observed problems. Other patches could be considered fixes too
if folks want.

I tested the first patch in the series backported to kernel 6.6 on the
Pixel phone that was experiencing the race. I added extra printouts to
make sure that the problem was hitting / addressed. The rest of the
patches are tested with allmodconfig with arm32, arm64, ppc, and
x86. I boot tested on an arm64 Chromebook running mainline.

Changes in v4:
- Use accessor functions for flags

Changes in v3:
- Use a new "flags" bitfield
- Add missing \n in probe error message

Changes in v2:
- Instead of adjusting the ordering, use "ready_to_probe" flag

Douglas Anderson (9):
  driver core: Don't let a device probe until it's ready
  driver core: Replace dev->can_match with dev_can_match()
  driver core: Replace dev->dma_iommu with dev_dma_iommu()
  driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync()
  driver core: Replace dev->dma_ops_bypass with dev_dma_ops_bypass()
  driver core: Replace dev->state_synced with dev_state_synced()
  driver core: Replace dev->dma_coherent with dev_dma_coherent()
  driver core: Replace dev->of_node_reused with dev_of_node_reused()
  driver core: Replace dev->offline + ->offline_disabled with accessors

 arch/arc/mm/dma.c                             |   4 +-
 arch/arm/mach-highbank/highbank.c             |   2 +-
 arch/arm/mach-mvebu/coherency.c               |   2 +-
 arch/arm/mm/dma-mapping-nommu.c               |   4 +-
 arch/arm/mm/dma-mapping.c                     |  28 ++--
 arch/arm64/kernel/cpufeature.c                |   2 +-
 arch/arm64/mm/dma-mapping.c                   |   2 +-
 arch/mips/mm/dma-noncoherent.c                |   2 +-
 arch/powerpc/kernel/dma-iommu.c               |   8 +-
 .../platforms/pseries/hotplug-memory.c        |   4 +-
 arch/riscv/mm/dma-noncoherent.c               |   2 +-
 drivers/acpi/scan.c                           |   2 +-
 drivers/base/core.c                           |  53 +++++---
 drivers/base/cpu.c                            |   4 +-
 drivers/base/dd.c                             |  28 ++--
 drivers/base/memory.c                         |   2 +-
 drivers/base/pinctrl.c                        |   2 +-
 drivers/base/platform.c                       |   2 +-
 drivers/dma/ti/k3-udma-glue.c                 |   6 +-
 drivers/dma/ti/k3-udma.c                      |   6 +-
 drivers/iommu/dma-iommu.c                     |   9 +-
 drivers/iommu/iommu.c                         |   5 +-
 drivers/net/pcs/pcs-xpcs-plat.c               |   2 +-
 drivers/of/device.c                           |   6 +-
 drivers/pci/of.c                              |   2 +-
 drivers/pci/pwrctrl/core.c                    |   2 +-
 drivers/regulator/bq257xx-regulator.c         |   2 +-
 drivers/regulator/rk808-regulator.c           |   2 +-
 drivers/tty/serial/serial_base_bus.c          |   2 +-
 drivers/usb/gadget/udc/aspeed-vhub/dev.c      |   2 +-
 include/linux/device.h                        | 120 ++++++++++++------
 include/linux/dma-map-ops.h                   |   6 +-
 include/linux/dma-mapping.h                   |   2 +-
 include/linux/iommu-dma.h                     |   3 +-
 kernel/cpu.c                                  |   4 +-
 kernel/dma/mapping.c                          |  12 +-
 mm/hmm.c                                      |   2 +-
 37 files changed, 206 insertions(+), 142 deletions(-)

-- 
2.53.0.1213.gd9a14994de-goog


^ permalink raw reply

* [PATCH v4 8/9] driver core: Replace dev->of_node_reused with dev_of_node_reused()
From: Douglas Anderson @ 2026-04-04  0:05 UTC (permalink / raw)
  To: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
	Alan Stern
  Cc: Saravana Kannan, Christoph Hellwig, Eric Dumazet, Johan Hovold,
	Leon Romanovsky, Alexander Lobakin, Alexey Kardashevskiy,
	Robin Murphy, Douglas Anderson, Mark Brown, alexander.stein,
	andrew, andrew, andriy.shevchenko, bhelgaas, brgl, davem,
	devicetree, driver-core, hkallweit1, jirislaby, joel, kees, kuba,
	lgirdwood, linux-arm-kernel, linux-aspeed, linux-kernel,
	linux-pci, linux-serial, linux-usb, linux, mani, netdev, pabeni,
	robh
In-Reply-To: <20260404000644.522677-1-dianders@chromium.org>

In C, bitfields are not necessarily safe to modify from multiple
threads without locking. Switch "of_node_reused" over to the "flags"
field so modifications are safe.

Cc: Johan Hovold <johan@kernel.org>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Not fixing any known bugs; problem is theoretical and found by code
inspection. Change is done somewhat manually and only lightly tested
(mostly compile-time tested).

Changes in v4:
- Use accessor functions for flags

Changes in v3:
- New

 drivers/base/core.c                      | 2 +-
 drivers/base/pinctrl.c                   | 2 +-
 drivers/base/platform.c                  | 2 +-
 drivers/net/pcs/pcs-xpcs-plat.c          | 2 +-
 drivers/of/device.c                      | 6 +++---
 drivers/pci/of.c                         | 2 +-
 drivers/pci/pwrctrl/core.c               | 2 +-
 drivers/regulator/bq257xx-regulator.c    | 2 +-
 drivers/regulator/rk808-regulator.c      | 2 +-
 drivers/tty/serial/serial_base_bus.c     | 2 +-
 drivers/usb/gadget/udc/aspeed-vhub/dev.c | 2 +-
 include/linux/device.h                   | 7 ++++---
 12 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 531f02a5469a..f12f3b53b4d0 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -5281,7 +5281,7 @@ void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
 {
 	of_node_put(dev->of_node);
 	dev->of_node = of_node_get(dev2->of_node);
-	dev->of_node_reused = true;
+	dev_set_of_node_reused(dev);
 }
 EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
 
diff --git a/drivers/base/pinctrl.c b/drivers/base/pinctrl.c
index 6e250272c843..0bbc83231234 100644
--- a/drivers/base/pinctrl.c
+++ b/drivers/base/pinctrl.c
@@ -24,7 +24,7 @@ int pinctrl_bind_pins(struct device *dev)
 {
 	int ret;
 
-	if (dev->of_node_reused)
+	if (dev_of_node_reused(dev))
 		return 0;
 
 	dev->pins = devm_kzalloc(dev, sizeof(*(dev->pins)), GFP_KERNEL);
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index d44591d52e36..199e6fb25770 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -856,7 +856,7 @@ struct platform_device *platform_device_register_full(
 	pdev->dev.parent = pdevinfo->parent;
 	pdev->dev.fwnode = pdevinfo->fwnode;
 	pdev->dev.of_node = of_node_get(to_of_node(pdev->dev.fwnode));
-	pdev->dev.of_node_reused = pdevinfo->of_node_reused;
+	dev_assign_of_node_reused(&pdev->dev, pdevinfo->of_node_reused);
 
 	if (pdevinfo->dma_mask) {
 		pdev->platform_dma_mask = pdevinfo->dma_mask;
diff --git a/drivers/net/pcs/pcs-xpcs-plat.c b/drivers/net/pcs/pcs-xpcs-plat.c
index b8c48f9effbf..f4b1b8246ce9 100644
--- a/drivers/net/pcs/pcs-xpcs-plat.c
+++ b/drivers/net/pcs/pcs-xpcs-plat.c
@@ -349,7 +349,7 @@ static int xpcs_plat_init_dev(struct dw_xpcs_plat *pxpcs)
 	 * up later. Make sure DD-core is aware of the OF-node being re-used.
 	 */
 	device_set_node(&mdiodev->dev, fwnode_handle_get(dev_fwnode(dev)));
-	mdiodev->dev.of_node_reused = true;
+	dev_set_of_node_reused(&mdiodev->dev);
 
 	/* Pass the data further so the DW XPCS driver core could use it */
 	mdiodev->dev.platform_data = (void *)device_get_match_data(dev);
diff --git a/drivers/of/device.c b/drivers/of/device.c
index f7e75e527667..be4e1584e0af 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -26,7 +26,7 @@
 const struct of_device_id *of_match_device(const struct of_device_id *matches,
 					   const struct device *dev)
 {
-	if (!matches || !dev->of_node || dev->of_node_reused)
+	if (!matches || !dev->of_node || dev_of_node_reused(dev))
 		return NULL;
 	return of_match_node(matches, dev->of_node);
 }
@@ -192,7 +192,7 @@ ssize_t of_device_modalias(struct device *dev, char *str, ssize_t len)
 {
 	ssize_t sl;
 
-	if (!dev || !dev->of_node || dev->of_node_reused)
+	if (!dev || !dev->of_node || dev_of_node_reused(dev))
 		return -ENODEV;
 
 	sl = of_modalias(dev->of_node, str, len - 2);
@@ -254,7 +254,7 @@ int of_device_uevent_modalias(const struct device *dev, struct kobj_uevent_env *
 {
 	int sl;
 
-	if ((!dev) || (!dev->of_node) || dev->of_node_reused)
+	if ((!dev) || (!dev->of_node) || dev_of_node_reused(dev))
 		return -ENODEV;
 
 	/* Devicetree modalias is tricky, we add it in 2 steps */
diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index 9f8eb5df279e..1f9b669abdb0 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -38,7 +38,7 @@ int pci_set_of_node(struct pci_dev *dev)
 	struct device *pdev __free(put_device) =
 		bus_find_device_by_of_node(&platform_bus_type, node);
 	if (pdev)
-		dev->bus->dev.of_node_reused = true;
+		dev_set_of_node_reused(&dev->bus->dev);
 
 	device_set_node(&dev->dev, of_fwnode_handle(no_free_ptr(node)));
 	return 0;
diff --git a/drivers/pci/pwrctrl/core.c b/drivers/pci/pwrctrl/core.c
index 7754baed67f2..72963a92362a 100644
--- a/drivers/pci/pwrctrl/core.c
+++ b/drivers/pci/pwrctrl/core.c
@@ -39,7 +39,7 @@ static int pci_pwrctrl_notify(struct notifier_block *nb, unsigned long action,
 		 * If we got here then the PCI device is the second after the
 		 * power control platform device. Mark its OF node as reused.
 		 */
-		dev->of_node_reused = true;
+		dev_set_of_node_reused(dev);
 		break;
 	}
 
diff --git a/drivers/regulator/bq257xx-regulator.c b/drivers/regulator/bq257xx-regulator.c
index dab8f1ab4450..40e0f1a7ae81 100644
--- a/drivers/regulator/bq257xx-regulator.c
+++ b/drivers/regulator/bq257xx-regulator.c
@@ -143,7 +143,7 @@ static int bq257xx_regulator_probe(struct platform_device *pdev)
 	struct regulator_config cfg = {};
 
 	pdev->dev.of_node = pdev->dev.parent->of_node;
-	pdev->dev.of_node_reused = true;
+	dev_set_of_node_reused(&pdev->dev);
 
 	pdata = devm_kzalloc(&pdev->dev, sizeof(struct bq257xx_reg_data), GFP_KERNEL);
 	if (!pdata)
diff --git a/drivers/regulator/rk808-regulator.c b/drivers/regulator/rk808-regulator.c
index e66408f23bb6..8297d31cde9f 100644
--- a/drivers/regulator/rk808-regulator.c
+++ b/drivers/regulator/rk808-regulator.c
@@ -2115,7 +2115,7 @@ static int rk808_regulator_probe(struct platform_device *pdev)
 	int ret, i, nregulators;
 
 	pdev->dev.of_node = pdev->dev.parent->of_node;
-	pdev->dev.of_node_reused = true;
+	dev_set_of_node_reused(&pdev->dev);
 
 	regmap = dev_get_regmap(pdev->dev.parent, NULL);
 	if (!regmap)
diff --git a/drivers/tty/serial/serial_base_bus.c b/drivers/tty/serial/serial_base_bus.c
index a12935f6b992..5f23284a8778 100644
--- a/drivers/tty/serial/serial_base_bus.c
+++ b/drivers/tty/serial/serial_base_bus.c
@@ -74,7 +74,7 @@ static int serial_base_device_init(struct uart_port *port,
 	dev->parent = parent_dev;
 	dev->bus = &serial_base_bus_type;
 	dev->release = release;
-	dev->of_node_reused = true;
+	dev_set_of_node_reused(dev);
 
 	device_set_node(dev, fwnode_handle_get(dev_fwnode(parent_dev)));
 
diff --git a/drivers/usb/gadget/udc/aspeed-vhub/dev.c b/drivers/usb/gadget/udc/aspeed-vhub/dev.c
index 2ecd049dacc2..8b9449d16324 100644
--- a/drivers/usb/gadget/udc/aspeed-vhub/dev.c
+++ b/drivers/usb/gadget/udc/aspeed-vhub/dev.c
@@ -593,7 +593,7 @@ int ast_vhub_init_dev(struct ast_vhub *vhub, unsigned int idx)
 		d->gadget.max_speed = USB_SPEED_HIGH;
 	d->gadget.speed = USB_SPEED_UNKNOWN;
 	d->gadget.dev.of_node = vhub->pdev->dev.of_node;
-	d->gadget.dev.of_node_reused = true;
+	dev_set_of_node_reused(&d->gadget.dev);
 
 	rc = usb_add_gadget_udc(d->port_dev, &d->gadget);
 	if (rc != 0)
diff --git a/include/linux/device.h b/include/linux/device.h
index fca986cef2ed..8132aab17e04 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -483,6 +483,8 @@ struct device_physical_location {
  *		driver/bus sync_state() callback.
  * @DEV_FLAG_DMA_COHERENT: This particular device is dma coherent, even if the
  *		architecture supports non-coherent devices.
+ * @DEV_FLAG_OF_NODE_REUSED: Set if the device-tree node is shared with an
+ *		ancestor device.
  */
 enum struct_device_flags {
 	DEV_FLAG_READY_TO_PROBE = 0,
@@ -492,6 +494,7 @@ enum struct_device_flags {
 	DEV_FLAG_DMA_OPS_BYPASS = 4,
 	DEV_FLAG_STATE_SYNCED = 5,
 	DEV_FLAG_DMA_COHERENT = 6,
+	DEV_FLAG_OF_NODE_REUSED = 7,
 
 	DEV_FLAG_COUNT
 };
@@ -573,8 +576,6 @@ enum struct_device_flags {
  *
  * @offline_disabled: If set, the device is permanently online.
  * @offline:	Set after successful invocation of bus type's .offline().
- * @of_node_reused: Set if the device-tree node is shared with an ancestor
- *              device.
  * @flags:	DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
  *
  * At the lowest level, every device in a Linux system is represented by an
@@ -681,7 +682,6 @@ struct device {
 
 	bool			offline_disabled:1;
 	bool			offline:1;
-	bool			of_node_reused:1;
 
 	DECLARE_BITMAP(flags, DEV_FLAG_COUNT);
 };
@@ -715,6 +715,7 @@ __create_dev_flag_accessors(dma_skip_sync, DEV_FLAG_DMA_SKIP_SYNC);
 __create_dev_flag_accessors(dma_ops_bypass, DEV_FLAG_DMA_OPS_BYPASS);
 __create_dev_flag_accessors(state_synced, DEV_FLAG_STATE_SYNCED);
 __create_dev_flag_accessors(dma_coherent, DEV_FLAG_DMA_COHERENT);
+__create_dev_flag_accessors(of_node_reused, DEV_FLAG_OF_NODE_REUSED);
 
 /**
  * struct device_link - Device link representation.
-- 
2.53.0.1213.gd9a14994de-goog


^ permalink raw reply related

* Re: [PATCH v4 0/9] driver core: Fix some race conditions
From: Rafael J. Wysocki @ 2026-04-04 17:11 UTC (permalink / raw)
  To: Douglas Anderson
  Cc: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
	Alan Stern, Saravana Kannan, Christoph Hellwig, Eric Dumazet,
	Johan Hovold, Leon Romanovsky, Alexander Lobakin,
	Alexey Kardashevskiy, Robin Murphy, Andrew Morton, Frank.Li,
	Jason Gunthorpe, alex, alexander.stein, andre.przywara, andrew,
	andrew, andriy.shevchenko, aou, ardb, bhelgaas, brgl, broonie,
	catalin.marinas, chleroy, davem, david, devicetree, dmaengine,
	driver-core, gbatra, gregory.clement, hkallweit1, iommu,
	jirislaby, joel, joro, kees, kevin.brodsky, kuba, lenb, lgirdwood,
	linux-acpi, linux-arm-kernel, linux-aspeed, linux-cxl,
	linux-kernel, linux-mips, linux-mm, linux-pci, linux-riscv,
	linux-serial, linux-snps-arc, linux-usb, linux, linuxppc-dev,
	m.szyprowski, maddy, mani, maz, miko.lenczewski, mpe, netdev,
	npiggin, osalvador, oupton, pabeni, palmer, peter.ujfalusi,
	peterz, pjw, robh, sebastian.hesselbarth, tglx, tsbogend, vgupta,
	vkoul, will, willy, yangyicong, yeoreum.yun
In-Reply-To: <20260404000644.522677-1-dianders@chromium.org>

On Sat, Apr 4, 2026 at 2:07 AM Douglas Anderson <dianders@chromium.org> wrote:
>
> The main goal of this series is to fix the observed bug talked about
> in the first patch ("driver core: Don't let a device probe until it's
> ready"). That patch fixes a problem that has been observed in the real
> world and could land even if the rest of the patches are found
> unacceptable or need to be spun.
>
> That said, during patch review Danilo correctly pointed out that many
> of the bitfield accesses in "struct device" are unsafe. I added a
> bunch of patches in the series to address each one.
>
> Danilo said he's most worried about "can_match", so I put that one
> first. After that, I tried to transition bitfields to flags in reverse
> order to when the bitfield was added.
>
> Even if transitioning from bitfields to flags isn't truly needed for
> correctness, it seems silly (and wasteful of space in struct device)
> to have some in bitfields and some as flags. Thus I didn't spend time
> for each bitfield showing that it's truly needed for correctness.
>
> Transition was done semi manually. Presumably someone skilled at
> coccinelle could do a better job, but I just used sed in a heavy-
> handed manner and then reviewed/fixed the results, undoing anything my
> script got wrong. My terrible/ugly script was:
>
> var=can_match
> caps="${var^^}"
> for f in $(git grep -l "[>\.]${var}[^1-9_a-zA-Z\[]"); do
>   echo $f
>   sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = true/set_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
>   sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = true/dev_set_${caps}(\&\\1)/" "$f"
>   sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = false/clear_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
>   sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = false/dev_clear_${caps}(\&\\1)/" "$f"
>   sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = \([^;]*\)/assign_bit(DEV_FLAG_${caps}, \&\\1->flags, \\2)/" "$f"
>   sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = \([^;]*\)/dev_assign_${caps}(\&\\1, \\2)/" "$f"
>   sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var}\([^1-9_a-zA-Z\[]\)/test_bit(DEV_FLAG_${caps}, \&\\1->flags)\\2/" "$f"
>   sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var}\([^1-9_a-zA-Z\[]\)/dev_${caps}(\&\\1)\\2/" "$f"
> done
>
> From v3 to v4, I transitioned to accessor functions with another ugly
> sed script. I had git format the old patches, then transformed them
> with:
>
> for f in *.patch; do
>   echo $f
>   sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
>   sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
>   sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_\\L\\1(\\2)/" "$f"
>   sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_\\L\\1(\\2)/" "$f"
>   sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_set_\\L\\1(\\2)/" "$f"
>   sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_set_\\L\\1(\\2)/" "$f"
>   sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_clear_\\L\\1(\\2)/" "$f"
>   sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_clear_\\L\\1(\\2)/" "$f"
>   sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
>   sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
> done
>
> ...and then did a few manual touchups for spacing.
>
> NOTE: one potentially "controversial" choice I made in some patches
> was to always reserve a flag ID even if a flag is only used under
> certain CONFIG_ settings. This is a change from how things were
> before. Keeping the numbering consistent and allowing easy
> compile-testing of both CONFIG settings seemed worth it, especially
> since it won't take up any extra space until we've added a lot more
> flags.
>
> I only marked the first patch as a "Fix" since it is the only one
> fixing observed problems. Other patches could be considered fixes too
> if folks want.
>
> I tested the first patch in the series backported to kernel 6.6 on the
> Pixel phone that was experiencing the race. I added extra printouts to
> make sure that the problem was hitting / addressed. The rest of the
> patches are tested with allmodconfig with arm32, arm64, ppc, and
> x86. I boot tested on an arm64 Chromebook running mainline.
>
> Changes in v4:
> - Use accessor functions for flags
>
> Changes in v3:
> - Use a new "flags" bitfield
> - Add missing \n in probe error message
>
> Changes in v2:
> - Instead of adjusting the ordering, use "ready_to_probe" flag
>
> Douglas Anderson (9):
>   driver core: Don't let a device probe until it's ready
>   driver core: Replace dev->can_match with dev_can_match()
>   driver core: Replace dev->dma_iommu with dev_dma_iommu()
>   driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync()
>   driver core: Replace dev->dma_ops_bypass with dev_dma_ops_bypass()
>   driver core: Replace dev->state_synced with dev_state_synced()
>   driver core: Replace dev->dma_coherent with dev_dma_coherent()
>   driver core: Replace dev->of_node_reused with dev_of_node_reused()
>   driver core: Replace dev->offline + ->offline_disabled with accessors
>
>  arch/arc/mm/dma.c                             |   4 +-
>  arch/arm/mach-highbank/highbank.c             |   2 +-
>  arch/arm/mach-mvebu/coherency.c               |   2 +-
>  arch/arm/mm/dma-mapping-nommu.c               |   4 +-
>  arch/arm/mm/dma-mapping.c                     |  28 ++--
>  arch/arm64/kernel/cpufeature.c                |   2 +-
>  arch/arm64/mm/dma-mapping.c                   |   2 +-
>  arch/mips/mm/dma-noncoherent.c                |   2 +-
>  arch/powerpc/kernel/dma-iommu.c               |   8 +-
>  .../platforms/pseries/hotplug-memory.c        |   4 +-
>  arch/riscv/mm/dma-noncoherent.c               |   2 +-
>  drivers/acpi/scan.c                           |   2 +-
>  drivers/base/core.c                           |  53 +++++---
>  drivers/base/cpu.c                            |   4 +-
>  drivers/base/dd.c                             |  28 ++--
>  drivers/base/memory.c                         |   2 +-
>  drivers/base/pinctrl.c                        |   2 +-
>  drivers/base/platform.c                       |   2 +-
>  drivers/dma/ti/k3-udma-glue.c                 |   6 +-
>  drivers/dma/ti/k3-udma.c                      |   6 +-
>  drivers/iommu/dma-iommu.c                     |   9 +-
>  drivers/iommu/iommu.c                         |   5 +-
>  drivers/net/pcs/pcs-xpcs-plat.c               |   2 +-
>  drivers/of/device.c                           |   6 +-
>  drivers/pci/of.c                              |   2 +-
>  drivers/pci/pwrctrl/core.c                    |   2 +-
>  drivers/regulator/bq257xx-regulator.c         |   2 +-
>  drivers/regulator/rk808-regulator.c           |   2 +-
>  drivers/tty/serial/serial_base_bus.c          |   2 +-
>  drivers/usb/gadget/udc/aspeed-vhub/dev.c      |   2 +-
>  include/linux/device.h                        | 120 ++++++++++++------
>  include/linux/dma-map-ops.h                   |   6 +-
>  include/linux/dma-mapping.h                   |   2 +-
>  include/linux/iommu-dma.h                     |   3 +-
>  kernel/cpu.c                                  |   4 +-
>  kernel/dma/mapping.c                          |  12 +-
>  mm/hmm.c                                      |   2 +-
>  37 files changed, 206 insertions(+), 142 deletions(-)
>
> --

For the whole set

Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>

^ permalink raw reply

* Re: [PATCH v4 0/9] driver core: Fix some race conditions
From: Greg Kroah-Hartman @ 2026-04-05  5:27 UTC (permalink / raw)
  To: Douglas Anderson
  Cc: Rafael J . Wysocki, Danilo Krummrich, Alan Stern, Saravana Kannan,
	Christoph Hellwig, Eric Dumazet, Johan Hovold, Leon Romanovsky,
	Alexander Lobakin, Alexey Kardashevskiy, Robin Murphy,
	Andrew Morton, Frank.Li, Jason Gunthorpe, alex, alexander.stein,
	andre.przywara, andrew, andrew, andriy.shevchenko, aou, ardb,
	bhelgaas, brgl, broonie, catalin.marinas, chleroy, davem, david,
	devicetree, dmaengine, driver-core, gbatra, gregory.clement,
	hkallweit1, iommu, jirislaby, joel, joro, kees, kevin.brodsky,
	kuba, lenb, lgirdwood, linux-acpi, linux-arm-kernel, linux-aspeed,
	linux-cxl, linux-kernel, linux-mips, linux-mm, linux-pci,
	linux-riscv, linux-serial, linux-snps-arc, linux-usb, linux,
	linuxppc-dev, m.szyprowski, maddy, mani, maz, miko.lenczewski,
	mpe, netdev, npiggin, osalvador, oupton, pabeni, palmer,
	peter.ujfalusi, peterz, pjw, robh, sebastian.hesselbarth, tglx,
	tsbogend, vgupta, vkoul, will, willy, yangyicong, yeoreum.yun
In-Reply-To: <20260404000644.522677-1-dianders@chromium.org>

On Fri, Apr 03, 2026 at 05:04:54PM -0700, Douglas Anderson wrote:
> NOTE: one potentially "controversial" choice I made in some patches
> was to always reserve a flag ID even if a flag is only used under
> certain CONFIG_ settings. This is a change from how things were
> before. Keeping the numbering consistent and allowing easy
> compile-testing of both CONFIG settings seemed worth it, especially
> since it won't take up any extra space until we've added a lot more
> flags.

Nah, this is fine, I don't see any problems with this as the original
code kind of was doing the same thing with the "hole" in the structure
if those options were not enabled.

> I only marked the first patch as a "Fix" since it is the only one
> fixing observed problems. Other patches could be considered fixes too
> if folks want.
> 
> I tested the first patch in the series backported to kernel 6.6 on the
> Pixel phone that was experiencing the race. I added extra printouts to
> make sure that the problem was hitting / addressed. The rest of the
> patches are tested with allmodconfig with arm32, arm64, ppc, and
> x86. I boot tested on an arm64 Chromebook running mainline.

I'm guessing your tests passed?  :)

Anyway, this looks great, unless there are any objections, other than
the "needs to be undefined", which a follow-on patch can handle, I'll
queue them up next week for 7.1-rc1.

thanks,

greg k-h

^ permalink raw reply

* [GIT PULL] TTY driver fixes for 7.0-rc7
From: Greg KH @ 2026-04-05  8:31 UTC (permalink / raw)
  To: Linus Torvalds; +Cc: Jiri Slaby, Andrew Morton, linux-kernel, linux-serial

The following changes since commit c369299895a591d96745d6492d4888259b004a9e:

  Linux 7.0-rc5 (2026-03-22 14:42:17 -0700)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tags/tty-7.0-rc7

for you to fetch changes up to 3ddbea7542ae529c1a88ef9a8b1ce169126211f6:

  vt: resize saved unicode buffer on alt screen exit after resize (2026-03-30 17:39:44 +0200)

----------------------------------------------------------------
TTY core fixes for 7.0-rc7

Here are 2 small tty vt fixes for 7.0-rc7 to resolve some reported
issues with the resize ability of the alt screen buffer.  Both of these
have been in linux-next all week with no reported issues.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

----------------------------------------------------------------
Liav Mordouch (1):
      vt: discard stale unicode buffer on alt screen exit after resize

Nicolas Pitre (1):
      vt: resize saved unicode buffer on alt screen exit after resize

 drivers/tty/vt/vt.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

^ permalink raw reply

* Re: [PATCH v4 0/9] driver core: Fix some race conditions
From: Danilo Krummrich @ 2026-04-05 12:02 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Douglas Anderson, Rafael J . Wysocki, Alan Stern, Saravana Kannan,
	Christoph Hellwig, Eric Dumazet, Johan Hovold, Leon Romanovsky,
	Alexander Lobakin, Alexey Kardashevskiy, Robin Murphy,
	Andrew Morton, Frank.Li, Jason Gunthorpe, alex, alexander.stein,
	andre.przywara, andrew, andrew, andriy.shevchenko, aou, ardb,
	bhelgaas, brgl, broonie, catalin.marinas, chleroy, davem, david,
	devicetree, dmaengine, driver-core, gbatra, gregory.clement,
	hkallweit1, iommu, jirislaby, joel, joro, kees, kevin.brodsky,
	kuba, lenb, lgirdwood, linux-acpi, linux-arm-kernel, linux-aspeed,
	linux-cxl, linux-kernel, linux-mips, linux-mm, linux-pci,
	linux-riscv, linux-serial, linux-snps-arc, linux-usb, linux,
	linuxppc-dev, m.szyprowski, maddy, mani, maz, miko.lenczewski,
	mpe, netdev, npiggin, osalvador, oupton, pabeni, palmer,
	peter.ujfalusi, peterz, pjw, robh, sebastian.hesselbarth, tglx,
	tsbogend, vgupta, vkoul, will, willy, yangyicong, yeoreum.yun
In-Reply-To: <2026040539-sponge-publisher-2b42@gregkh>

On Sun Apr 5, 2026 at 7:27 AM CEST, Greg Kroah-Hartman wrote:
> Anyway, this looks great, unless there are any objections, other than
> the "needs to be undefined", which a follow-on patch can handle, I'll
> queue them up next week for 7.1-rc1.

Sounds good, for the series:

Reviewed-by: Danilo Krummrich <dakr@kernel.org>

^ permalink raw reply

* Re: [GIT PULL] TTY driver fixes for 7.0-rc7
From: pr-tracker-bot @ 2026-04-05 17:13 UTC (permalink / raw)
  To: Greg KH
  Cc: Linus Torvalds, Jiri Slaby, Andrew Morton, linux-kernel,
	linux-serial
In-Reply-To: <adId31g54PFsRJ_s@kroah.com>

The pull request you sent on Sun, 5 Apr 2026 10:31:27 +0200:

> git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tags/tty-7.0-rc7

has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/7a60c79bd0547adba3cefde40ced4a1f376305be

Thank you!

-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/prtracker.html

^ permalink raw reply

* Re: [PATCH v4 0/9] driver core: Fix some race conditions
From: Doug Anderson @ 2026-04-05 22:43 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Rafael J . Wysocki, Danilo Krummrich, Alan Stern, Saravana Kannan,
	Christoph Hellwig, Eric Dumazet, Johan Hovold, Leon Romanovsky,
	Alexander Lobakin, Alexey Kardashevskiy, Robin Murphy,
	Andrew Morton, Frank.Li, Jason Gunthorpe, alex, alexander.stein,
	andre.przywara, andrew, andrew, andriy.shevchenko, aou, ardb,
	bhelgaas, brgl, broonie, catalin.marinas, chleroy, davem, david,
	devicetree, dmaengine, driver-core, gbatra, gregory.clement,
	hkallweit1, iommu, jirislaby, joel, joro, kees, kevin.brodsky,
	kuba, lenb, lgirdwood, linux-acpi, linux-arm-kernel, linux-aspeed,
	linux-cxl, linux-kernel, linux-mips, linux-mm, linux-pci,
	linux-riscv, linux-serial, linux-snps-arc, linux-usb, linux,
	linuxppc-dev, m.szyprowski, maddy, mani, maz, miko.lenczewski,
	mpe, netdev, npiggin, osalvador, oupton, pabeni, palmer,
	peter.ujfalusi, peterz, pjw, robh, sebastian.hesselbarth, tglx,
	tsbogend, vgupta, vkoul, will, willy, yangyicong, yeoreum.yun
In-Reply-To: <2026040539-sponge-publisher-2b42@gregkh>

Hi,

On Sat, Apr 4, 2026 at 10:28 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Fri, Apr 03, 2026 at 05:04:54PM -0700, Douglas Anderson wrote:
> > NOTE: one potentially "controversial" choice I made in some patches
> > was to always reserve a flag ID even if a flag is only used under
> > certain CONFIG_ settings. This is a change from how things were
> > before. Keeping the numbering consistent and allowing easy
> > compile-testing of both CONFIG settings seemed worth it, especially
> > since it won't take up any extra space until we've added a lot more
> > flags.
>
> Nah, this is fine, I don't see any problems with this as the original
> code kind of was doing the same thing with the "hole" in the structure
> if those options were not enabled.
>
> > I only marked the first patch as a "Fix" since it is the only one
> > fixing observed problems. Other patches could be considered fixes too
> > if folks want.
> >
> > I tested the first patch in the series backported to kernel 6.6 on the
> > Pixel phone that was experiencing the race. I added extra printouts to
> > make sure that the problem was hitting / addressed. The rest of the
> > patches are tested with allmodconfig with arm32, arm64, ppc, and
> > x86. I boot tested on an arm64 Chromebook running mainline.
>
> I'm guessing your tests passed?  :)

Yup, all the tests that I've run have passed. I also threw in an
"allnoconfig" compile test just for good measure.


> Anyway, this looks great, unless there are any objections, other than
> the "needs to be undefined", which a follow-on patch can handle, I'll
> queue them up next week for 7.1-rc1.

Thanks. As per the other thread, I'm happy if you or Danilo want to
apply it, and I'm happy if you want to make minor fixups when
applying.

When I see the patches applied, I'll send a followup patch to address
the "needs to be undefined" comment, unless Danilo makes that change
himself when applying.

-Doug

^ permalink raw reply

* Re: [PATCH v2] MIPS: dts: loongson64g-package: Switch to Loongson UART driver
From: Thomas Bogendoerfer @ 2026-04-06 12:32 UTC (permalink / raw)
  To: Rong Zhang
  Cc: Greg Kroah-Hartman, Jiri Slaby, Rob Herring, Krzysztof Kozlowski,
	Conor Dooley, Huacai Chen, Jiaxun Yang, linux-kernel,
	linux-serial, linux-mips, devicetree, Yao Zi, Icenowy Zheng,
	Rong Zhang
In-Reply-To: <20260315184401.413975-1-rongrong@oss.cipunited.com>

On Mon, Mar 16, 2026 at 02:44:00AM +0800, Rong Zhang wrote:
> Loongson64g is Loongson 3A4000, whose UART controller is compatible with
> Loongson 2K1500, which is NS16550A-compatible with an additional
> fractional frequency divisor register.
> 
> Update the compatible strings to reflect this, so that 3A4000 can
> benefit from the fractional frequency divisor provided by loongson-uart.
> This is required on some devices, otherwise their UART can't work at
> some high baud rates, e.g., 115200.
> 
> Tested on Loongson-LS3A4000-7A1000-NUC-SE with a 25MHz UART clock.
> Without fractional frequency divisor, the actual baud rate was 111607
> (25MHz / 16 / 14, measured value: 111545) and some USB-to-UART
> converters couldn't work with it at all. With fractional frequency
> divisor, the measured baud rate becomes 115207, which is quite accurate.
> 
> Signed-off-by: Rong Zhang <rongrong@oss.cipunited.com>
> ---
> This patch targets the MIPS tree.
> 
> The series for the serial tree to update dt-bindings and enable building
> 8250_loongson (loongson-uart) on MIPS Loongson64 is sent separately, as
> it's independant of this patch and can be applied in any order (the
> compatible strings here still contain "ns16550a", so no regression will
> be introduced).
> 
> Changes in v2:
> - Separated from v1 (patch 3): https://lore.kernel.org/r/20260314234143.651298-1-rongrong@oss.cipunited.com/
> (thanks Krzysztof Kozlowski)
> ---
>  arch/mips/boot/dts/loongson/loongson64g-package.dtsi | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

applied to mips-next

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]

^ permalink raw reply

* [PATCH v5 0/9] driver core: Fix some race conditions
From: Douglas Anderson @ 2026-04-06 23:22 UTC (permalink / raw)
  To: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
	Alan Stern
  Cc: Alexey Kardashevskiy, Johan Hovold, Eric Dumazet, Leon Romanovsky,
	Christoph Hellwig, Robin Murphy, maz, Alexander Lobakin,
	Saravana Kannan, Douglas Anderson, Andrew Morton, Frank.Li,
	Jason Gunthorpe, alex, alexander.stein, andre.przywara, andrew,
	andrew, andriy.shevchenko, aou, ardb, astewart, bhelgaas, brgl,
	broonie, catalin.marinas, chleroy, davem, david, devicetree,
	dmaengine, driver-core, gbatra, gregory.clement, hkallweit1,
	iommu, jirislaby, joel, joro, kees, kevin.brodsky, kuba, lenb,
	lgirdwood, linux-acpi, linux-arm-kernel, linux-aspeed, linux-cxl,
	linux-kernel, linux-mips, linux-mm, linux-pci, linux-riscv,
	linux-serial, linux-snps-arc, linux-usb, linux, linuxppc-dev,
	m.szyprowski, maddy, mani, miko.lenczewski, mpe, netdev, npiggin,
	osalvador, oupton, pabeni, palmer, peter.ujfalusi, peterz, pjw,
	robh, sebastian.hesselbarth, tglx, tsbogend, vgupta, vkoul, will,
	willy, yangyicong, yeoreum.yun

The main goal of this series is to fix the observed bug talked about
in the first patch ("driver core: Don't let a device probe until it's
ready"). That patch fixes a problem that has been observed in the real
world and could land even if the rest of the patches are found
unacceptable or need to be spun.

That said, during patch review Danilo correctly pointed out that many
of the bitfield accesses in "struct device" are unsafe. I added a
bunch of patches in the series to address each one.

Danilo said he's most worried about "can_match", so I put that one
first. After that, I tried to transition bitfields to flags in reverse
order to when the bitfield was added.

Even if transitioning from bitfields to flags isn't truly needed for
correctness, it seems silly (and wasteful of space in struct device)
to have some in bitfields and some as flags. Thus I didn't spend time
for each bitfield showing that it's truly needed for correctness.

Transition was done semi manually. Presumably someone skilled at
coccinelle could do a better job, but I just used sed in a heavy-
handed manner and then reviewed/fixed the results, undoing anything my
script got wrong. My terrible/ugly script was:

var=can_match
caps="${var^^}"
for f in $(git grep -l "[>\.]${var}[^1-9_a-zA-Z\[]"); do
  echo $f
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = true/set_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = true/dev_set_${caps}(\&\\1)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = false/clear_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = false/dev_clear_${caps}(\&\\1)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = \([^;]*\)/assign_bit(DEV_FLAG_${caps}, \&\\1->flags, \\2)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = \([^;]*\)/dev_assign_${caps}(\&\\1, \\2)/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var}\([^1-9_a-zA-Z\[]\)/test_bit(DEV_FLAG_${caps}, \&\\1->flags)\\2/" "$f"
  sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var}\([^1-9_a-zA-Z\[]\)/dev_${caps}(\&\\1)\\2/" "$f"
done

From v3 to v4, I transitioned to accessor functions with another ugly
sed script. I had git format the old patches, then transformed them
with:

for f in *.patch; do
  echo $f
  sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_test_and_set_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_set_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_set_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_clear_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_clear_\\L\\1(\\2)/" "$f"
  sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
  sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f"
done

...and then did a few manual touchups for spacing.

I only marked the first patch as a "Fix" since it is the only one
fixing observed problems. Other patches could be considered fixes too
if folks want.

I tested the first patch in the series backported to kernel 6.6 on the
Pixel phone that was experiencing the race. I added extra printouts to
make sure that the problem was hitting / addressed. The rest of the
patches are tested with allmodconfig with arm32, arm64, ppc, and
x86. I boot tested on an arm64 Chromebook running mainline.

Changes in v5:
- ready_to_prove => ready_to_probe typo
- device_lock() while calling dev_set_ready_to_probe()
- Add comment before "can_match = true" from Danilo.
- undef __create_dev_flag_accessors

Changes in v4:
- Use accessor functions for flags

Changes in v3:
- Use a new "flags" bitfield
- Add missing \n in probe error message

Changes in v2:
- Instead of adjusting the ordering, use "ready_to_probe" flag

Douglas Anderson (9):
  driver core: Don't let a device probe until it's ready
  driver core: Replace dev->can_match with dev_can_match()
  driver core: Replace dev->dma_iommu with dev_dma_iommu()
  driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync()
  driver core: Replace dev->dma_ops_bypass with dev_dma_ops_bypass()
  driver core: Replace dev->state_synced with dev_state_synced()
  driver core: Replace dev->dma_coherent with dev_dma_coherent()
  driver core: Replace dev->of_node_reused with dev_of_node_reused()
  driver core: Replace dev->offline + ->offline_disabled with accessors

 arch/arc/mm/dma.c                             |   4 +-
 arch/arm/mach-highbank/highbank.c             |   2 +-
 arch/arm/mach-mvebu/coherency.c               |   2 +-
 arch/arm/mm/dma-mapping-nommu.c               |   4 +-
 arch/arm/mm/dma-mapping.c                     |  28 ++--
 arch/arm64/kernel/cpufeature.c                |   2 +-
 arch/arm64/mm/dma-mapping.c                   |   2 +-
 arch/mips/mm/dma-noncoherent.c                |   2 +-
 arch/powerpc/kernel/dma-iommu.c               |   8 +-
 .../platforms/pseries/hotplug-memory.c        |   4 +-
 arch/riscv/mm/dma-noncoherent.c               |   2 +-
 drivers/acpi/scan.c                           |   2 +-
 drivers/base/core.c                           |  55 +++++---
 drivers/base/cpu.c                            |   4 +-
 drivers/base/dd.c                             |  36 ++++--
 drivers/base/memory.c                         |   2 +-
 drivers/base/pinctrl.c                        |   2 +-
 drivers/base/platform.c                       |   2 +-
 drivers/dma/ti/k3-udma-glue.c                 |   6 +-
 drivers/dma/ti/k3-udma.c                      |   6 +-
 drivers/iommu/dma-iommu.c                     |   9 +-
 drivers/iommu/iommu.c                         |   5 +-
 drivers/net/pcs/pcs-xpcs-plat.c               |   2 +-
 drivers/of/device.c                           |   6 +-
 drivers/pci/of.c                              |   2 +-
 drivers/pci/pwrctrl/core.c                    |   2 +-
 drivers/regulator/bq257xx-regulator.c         |   2 +-
 drivers/regulator/rk808-regulator.c           |   2 +-
 drivers/tty/serial/serial_base_bus.c          |   2 +-
 drivers/usb/gadget/udc/aspeed-vhub/dev.c      |   2 +-
 include/linux/device.h                        | 122 ++++++++++++------
 include/linux/dma-map-ops.h                   |   6 +-
 include/linux/dma-mapping.h                   |   2 +-
 include/linux/iommu-dma.h                     |   3 +-
 kernel/cpu.c                                  |   4 +-
 kernel/dma/mapping.c                          |  12 +-
 mm/hmm.c                                      |   2 +-
 37 files changed, 218 insertions(+), 142 deletions(-)

-- 
2.53.0.1213.gd9a14994de-goog


^ permalink raw reply

* [PATCH v5 8/9] driver core: Replace dev->of_node_reused with dev_of_node_reused()
From: Douglas Anderson @ 2026-04-06 23:23 UTC (permalink / raw)
  To: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
	Alan Stern
  Cc: Alexey Kardashevskiy, Johan Hovold, Eric Dumazet, Leon Romanovsky,
	Christoph Hellwig, Robin Murphy, maz, Alexander Lobakin,
	Saravana Kannan, Douglas Anderson, Mark Brown, alexander.stein,
	andrew, andrew, andriy.shevchenko, astewart, bhelgaas, brgl,
	davem, devicetree, driver-core, hkallweit1, jirislaby, joel, kees,
	kuba, lgirdwood, linux-arm-kernel, linux-aspeed, linux-kernel,
	linux-pci, linux-serial, linux-usb, linux, mani, netdev, pabeni,
	robh
In-Reply-To: <20260406232444.3117516-1-dianders@chromium.org>

In C, bitfields are not necessarily safe to modify from multiple
threads without locking. Switch "of_node_reused" over to the "flags"
field so modifications are safe.

Cc: Johan Hovold <johan@kernel.org>
Acked-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Not fixing any known bugs; problem is theoretical and found by code
inspection. Change is done somewhat manually and only lightly tested
(mostly compile-time tested).

(no changes since v4)

Changes in v4:
- Use accessor functions for flags

Changes in v3:
- New

 drivers/base/core.c                      | 2 +-
 drivers/base/pinctrl.c                   | 2 +-
 drivers/base/platform.c                  | 2 +-
 drivers/net/pcs/pcs-xpcs-plat.c          | 2 +-
 drivers/of/device.c                      | 6 +++---
 drivers/pci/of.c                         | 2 +-
 drivers/pci/pwrctrl/core.c               | 2 +-
 drivers/regulator/bq257xx-regulator.c    | 2 +-
 drivers/regulator/rk808-regulator.c      | 2 +-
 drivers/tty/serial/serial_base_bus.c     | 2 +-
 drivers/usb/gadget/udc/aspeed-vhub/dev.c | 2 +-
 include/linux/device.h                   | 7 ++++---
 12 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 8a83d7c93361..30825bf83234 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -5283,7 +5283,7 @@ void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
 {
 	of_node_put(dev->of_node);
 	dev->of_node = of_node_get(dev2->of_node);
-	dev->of_node_reused = true;
+	dev_set_of_node_reused(dev);
 }
 EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
 
diff --git a/drivers/base/pinctrl.c b/drivers/base/pinctrl.c
index 6e250272c843..0bbc83231234 100644
--- a/drivers/base/pinctrl.c
+++ b/drivers/base/pinctrl.c
@@ -24,7 +24,7 @@ int pinctrl_bind_pins(struct device *dev)
 {
 	int ret;
 
-	if (dev->of_node_reused)
+	if (dev_of_node_reused(dev))
 		return 0;
 
 	dev->pins = devm_kzalloc(dev, sizeof(*(dev->pins)), GFP_KERNEL);
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index d44591d52e36..199e6fb25770 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -856,7 +856,7 @@ struct platform_device *platform_device_register_full(
 	pdev->dev.parent = pdevinfo->parent;
 	pdev->dev.fwnode = pdevinfo->fwnode;
 	pdev->dev.of_node = of_node_get(to_of_node(pdev->dev.fwnode));
-	pdev->dev.of_node_reused = pdevinfo->of_node_reused;
+	dev_assign_of_node_reused(&pdev->dev, pdevinfo->of_node_reused);
 
 	if (pdevinfo->dma_mask) {
 		pdev->platform_dma_mask = pdevinfo->dma_mask;
diff --git a/drivers/net/pcs/pcs-xpcs-plat.c b/drivers/net/pcs/pcs-xpcs-plat.c
index b8c48f9effbf..f4b1b8246ce9 100644
--- a/drivers/net/pcs/pcs-xpcs-plat.c
+++ b/drivers/net/pcs/pcs-xpcs-plat.c
@@ -349,7 +349,7 @@ static int xpcs_plat_init_dev(struct dw_xpcs_plat *pxpcs)
 	 * up later. Make sure DD-core is aware of the OF-node being re-used.
 	 */
 	device_set_node(&mdiodev->dev, fwnode_handle_get(dev_fwnode(dev)));
-	mdiodev->dev.of_node_reused = true;
+	dev_set_of_node_reused(&mdiodev->dev);
 
 	/* Pass the data further so the DW XPCS driver core could use it */
 	mdiodev->dev.platform_data = (void *)device_get_match_data(dev);
diff --git a/drivers/of/device.c b/drivers/of/device.c
index f7e75e527667..be4e1584e0af 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -26,7 +26,7 @@
 const struct of_device_id *of_match_device(const struct of_device_id *matches,
 					   const struct device *dev)
 {
-	if (!matches || !dev->of_node || dev->of_node_reused)
+	if (!matches || !dev->of_node || dev_of_node_reused(dev))
 		return NULL;
 	return of_match_node(matches, dev->of_node);
 }
@@ -192,7 +192,7 @@ ssize_t of_device_modalias(struct device *dev, char *str, ssize_t len)
 {
 	ssize_t sl;
 
-	if (!dev || !dev->of_node || dev->of_node_reused)
+	if (!dev || !dev->of_node || dev_of_node_reused(dev))
 		return -ENODEV;
 
 	sl = of_modalias(dev->of_node, str, len - 2);
@@ -254,7 +254,7 @@ int of_device_uevent_modalias(const struct device *dev, struct kobj_uevent_env *
 {
 	int sl;
 
-	if ((!dev) || (!dev->of_node) || dev->of_node_reused)
+	if ((!dev) || (!dev->of_node) || dev_of_node_reused(dev))
 		return -ENODEV;
 
 	/* Devicetree modalias is tricky, we add it in 2 steps */
diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index 9f8eb5df279e..1f9b669abdb0 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -38,7 +38,7 @@ int pci_set_of_node(struct pci_dev *dev)
 	struct device *pdev __free(put_device) =
 		bus_find_device_by_of_node(&platform_bus_type, node);
 	if (pdev)
-		dev->bus->dev.of_node_reused = true;
+		dev_set_of_node_reused(&dev->bus->dev);
 
 	device_set_node(&dev->dev, of_fwnode_handle(no_free_ptr(node)));
 	return 0;
diff --git a/drivers/pci/pwrctrl/core.c b/drivers/pci/pwrctrl/core.c
index 7754baed67f2..72963a92362a 100644
--- a/drivers/pci/pwrctrl/core.c
+++ b/drivers/pci/pwrctrl/core.c
@@ -39,7 +39,7 @@ static int pci_pwrctrl_notify(struct notifier_block *nb, unsigned long action,
 		 * If we got here then the PCI device is the second after the
 		 * power control platform device. Mark its OF node as reused.
 		 */
-		dev->of_node_reused = true;
+		dev_set_of_node_reused(dev);
 		break;
 	}
 
diff --git a/drivers/regulator/bq257xx-regulator.c b/drivers/regulator/bq257xx-regulator.c
index dab8f1ab4450..40e0f1a7ae81 100644
--- a/drivers/regulator/bq257xx-regulator.c
+++ b/drivers/regulator/bq257xx-regulator.c
@@ -143,7 +143,7 @@ static int bq257xx_regulator_probe(struct platform_device *pdev)
 	struct regulator_config cfg = {};
 
 	pdev->dev.of_node = pdev->dev.parent->of_node;
-	pdev->dev.of_node_reused = true;
+	dev_set_of_node_reused(&pdev->dev);
 
 	pdata = devm_kzalloc(&pdev->dev, sizeof(struct bq257xx_reg_data), GFP_KERNEL);
 	if (!pdata)
diff --git a/drivers/regulator/rk808-regulator.c b/drivers/regulator/rk808-regulator.c
index e66408f23bb6..8297d31cde9f 100644
--- a/drivers/regulator/rk808-regulator.c
+++ b/drivers/regulator/rk808-regulator.c
@@ -2115,7 +2115,7 @@ static int rk808_regulator_probe(struct platform_device *pdev)
 	int ret, i, nregulators;
 
 	pdev->dev.of_node = pdev->dev.parent->of_node;
-	pdev->dev.of_node_reused = true;
+	dev_set_of_node_reused(&pdev->dev);
 
 	regmap = dev_get_regmap(pdev->dev.parent, NULL);
 	if (!regmap)
diff --git a/drivers/tty/serial/serial_base_bus.c b/drivers/tty/serial/serial_base_bus.c
index a12935f6b992..5f23284a8778 100644
--- a/drivers/tty/serial/serial_base_bus.c
+++ b/drivers/tty/serial/serial_base_bus.c
@@ -74,7 +74,7 @@ static int serial_base_device_init(struct uart_port *port,
 	dev->parent = parent_dev;
 	dev->bus = &serial_base_bus_type;
 	dev->release = release;
-	dev->of_node_reused = true;
+	dev_set_of_node_reused(dev);
 
 	device_set_node(dev, fwnode_handle_get(dev_fwnode(parent_dev)));
 
diff --git a/drivers/usb/gadget/udc/aspeed-vhub/dev.c b/drivers/usb/gadget/udc/aspeed-vhub/dev.c
index 2ecd049dacc2..8b9449d16324 100644
--- a/drivers/usb/gadget/udc/aspeed-vhub/dev.c
+++ b/drivers/usb/gadget/udc/aspeed-vhub/dev.c
@@ -593,7 +593,7 @@ int ast_vhub_init_dev(struct ast_vhub *vhub, unsigned int idx)
 		d->gadget.max_speed = USB_SPEED_HIGH;
 	d->gadget.speed = USB_SPEED_UNKNOWN;
 	d->gadget.dev.of_node = vhub->pdev->dev.of_node;
-	d->gadget.dev.of_node_reused = true;
+	dev_set_of_node_reused(&d->gadget.dev);
 
 	rc = usb_add_gadget_udc(d->port_dev, &d->gadget);
 	if (rc != 0)
diff --git a/include/linux/device.h b/include/linux/device.h
index 5b0fb6ad4c72..a79865a212e9 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -483,6 +483,8 @@ struct device_physical_location {
  *		driver/bus sync_state() callback.
  * @DEV_FLAG_DMA_COHERENT: This particular device is dma coherent, even if the
  *		architecture supports non-coherent devices.
+ * @DEV_FLAG_OF_NODE_REUSED: Set if the device-tree node is shared with an
+ *		ancestor device.
  */
 enum struct_device_flags {
 	DEV_FLAG_READY_TO_PROBE = 0,
@@ -492,6 +494,7 @@ enum struct_device_flags {
 	DEV_FLAG_DMA_OPS_BYPASS = 4,
 	DEV_FLAG_STATE_SYNCED = 5,
 	DEV_FLAG_DMA_COHERENT = 6,
+	DEV_FLAG_OF_NODE_REUSED = 7,
 
 	DEV_FLAG_COUNT
 };
@@ -573,8 +576,6 @@ enum struct_device_flags {
  *
  * @offline_disabled: If set, the device is permanently online.
  * @offline:	Set after successful invocation of bus type's .offline().
- * @of_node_reused: Set if the device-tree node is shared with an ancestor
- *              device.
  * @flags:	DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
  *
  * At the lowest level, every device in a Linux system is represented by an
@@ -681,7 +682,6 @@ struct device {
 
 	bool			offline_disabled:1;
 	bool			offline:1;
-	bool			of_node_reused:1;
 
 	DECLARE_BITMAP(flags, DEV_FLAG_COUNT);
 };
@@ -715,6 +715,7 @@ __create_dev_flag_accessors(dma_skip_sync, DEV_FLAG_DMA_SKIP_SYNC);
 __create_dev_flag_accessors(dma_ops_bypass, DEV_FLAG_DMA_OPS_BYPASS);
 __create_dev_flag_accessors(state_synced, DEV_FLAG_STATE_SYNCED);
 __create_dev_flag_accessors(dma_coherent, DEV_FLAG_DMA_COHERENT);
+__create_dev_flag_accessors(of_node_reused, DEV_FLAG_OF_NODE_REUSED);
 
 #undef __create_dev_flag_accessors
 
-- 
2.53.0.1213.gd9a14994de-goog


^ permalink raw reply related

* Re: [PATCH v5 8/9] driver core: Replace dev->of_node_reused with dev_of_node_reused()
From: Manivannan Sadhasivam @ 2026-04-07  7:27 UTC (permalink / raw)
  To: Douglas Anderson
  Cc: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
	Alan Stern, Alexey Kardashevskiy, Johan Hovold, Eric Dumazet,
	Leon Romanovsky, Christoph Hellwig, Robin Murphy, maz,
	Alexander Lobakin, Saravana Kannan, Mark Brown, alexander.stein,
	andrew, andrew, andriy.shevchenko, astewart, bhelgaas, brgl,
	davem, devicetree, driver-core, hkallweit1, jirislaby, joel, kees,
	kuba, lgirdwood, linux-arm-kernel, linux-aspeed, linux-kernel,
	linux-pci, linux-serial, linux-usb, linux, netdev, pabeni, robh
In-Reply-To: <20260406162231.v5.8.I806b8636cd3724f6cd1f5e199318ab8694472d90@changeid>

On Mon, Apr 06, 2026 at 04:23:01PM -0700, Douglas Anderson wrote:
> In C, bitfields are not necessarily safe to modify from multiple
> threads without locking. Switch "of_node_reused" over to the "flags"
> field so modifications are safe.
> 
> Cc: Johan Hovold <johan@kernel.org>
> Acked-by: Mark Brown <broonie@kernel.org>
> Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
> Reviewed-by: Danilo Krummrich <dakr@kernel.org>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>

Acked-by: Manivannan Sadhasivam <mani@kernel.org> # PCI_PWRCTRL

- Mani

> ---
> Not fixing any known bugs; problem is theoretical and found by code
> inspection. Change is done somewhat manually and only lightly tested
> (mostly compile-time tested).
> 
> (no changes since v4)
> 
> Changes in v4:
> - Use accessor functions for flags
> 
> Changes in v3:
> - New
> 
>  drivers/base/core.c                      | 2 +-
>  drivers/base/pinctrl.c                   | 2 +-
>  drivers/base/platform.c                  | 2 +-
>  drivers/net/pcs/pcs-xpcs-plat.c          | 2 +-
>  drivers/of/device.c                      | 6 +++---
>  drivers/pci/of.c                         | 2 +-
>  drivers/pci/pwrctrl/core.c               | 2 +-
>  drivers/regulator/bq257xx-regulator.c    | 2 +-
>  drivers/regulator/rk808-regulator.c      | 2 +-
>  drivers/tty/serial/serial_base_bus.c     | 2 +-
>  drivers/usb/gadget/udc/aspeed-vhub/dev.c | 2 +-
>  include/linux/device.h                   | 7 ++++---
>  12 files changed, 17 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 8a83d7c93361..30825bf83234 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -5283,7 +5283,7 @@ void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
>  {
>  	of_node_put(dev->of_node);
>  	dev->of_node = of_node_get(dev2->of_node);
> -	dev->of_node_reused = true;
> +	dev_set_of_node_reused(dev);
>  }
>  EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
>  
> diff --git a/drivers/base/pinctrl.c b/drivers/base/pinctrl.c
> index 6e250272c843..0bbc83231234 100644
> --- a/drivers/base/pinctrl.c
> +++ b/drivers/base/pinctrl.c
> @@ -24,7 +24,7 @@ int pinctrl_bind_pins(struct device *dev)
>  {
>  	int ret;
>  
> -	if (dev->of_node_reused)
> +	if (dev_of_node_reused(dev))
>  		return 0;
>  
>  	dev->pins = devm_kzalloc(dev, sizeof(*(dev->pins)), GFP_KERNEL);
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index d44591d52e36..199e6fb25770 100644
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -856,7 +856,7 @@ struct platform_device *platform_device_register_full(
>  	pdev->dev.parent = pdevinfo->parent;
>  	pdev->dev.fwnode = pdevinfo->fwnode;
>  	pdev->dev.of_node = of_node_get(to_of_node(pdev->dev.fwnode));
> -	pdev->dev.of_node_reused = pdevinfo->of_node_reused;
> +	dev_assign_of_node_reused(&pdev->dev, pdevinfo->of_node_reused);
>  
>  	if (pdevinfo->dma_mask) {
>  		pdev->platform_dma_mask = pdevinfo->dma_mask;
> diff --git a/drivers/net/pcs/pcs-xpcs-plat.c b/drivers/net/pcs/pcs-xpcs-plat.c
> index b8c48f9effbf..f4b1b8246ce9 100644
> --- a/drivers/net/pcs/pcs-xpcs-plat.c
> +++ b/drivers/net/pcs/pcs-xpcs-plat.c
> @@ -349,7 +349,7 @@ static int xpcs_plat_init_dev(struct dw_xpcs_plat *pxpcs)
>  	 * up later. Make sure DD-core is aware of the OF-node being re-used.
>  	 */
>  	device_set_node(&mdiodev->dev, fwnode_handle_get(dev_fwnode(dev)));
> -	mdiodev->dev.of_node_reused = true;
> +	dev_set_of_node_reused(&mdiodev->dev);
>  
>  	/* Pass the data further so the DW XPCS driver core could use it */
>  	mdiodev->dev.platform_data = (void *)device_get_match_data(dev);
> diff --git a/drivers/of/device.c b/drivers/of/device.c
> index f7e75e527667..be4e1584e0af 100644
> --- a/drivers/of/device.c
> +++ b/drivers/of/device.c
> @@ -26,7 +26,7 @@
>  const struct of_device_id *of_match_device(const struct of_device_id *matches,
>  					   const struct device *dev)
>  {
> -	if (!matches || !dev->of_node || dev->of_node_reused)
> +	if (!matches || !dev->of_node || dev_of_node_reused(dev))
>  		return NULL;
>  	return of_match_node(matches, dev->of_node);
>  }
> @@ -192,7 +192,7 @@ ssize_t of_device_modalias(struct device *dev, char *str, ssize_t len)
>  {
>  	ssize_t sl;
>  
> -	if (!dev || !dev->of_node || dev->of_node_reused)
> +	if (!dev || !dev->of_node || dev_of_node_reused(dev))
>  		return -ENODEV;
>  
>  	sl = of_modalias(dev->of_node, str, len - 2);
> @@ -254,7 +254,7 @@ int of_device_uevent_modalias(const struct device *dev, struct kobj_uevent_env *
>  {
>  	int sl;
>  
> -	if ((!dev) || (!dev->of_node) || dev->of_node_reused)
> +	if ((!dev) || (!dev->of_node) || dev_of_node_reused(dev))
>  		return -ENODEV;
>  
>  	/* Devicetree modalias is tricky, we add it in 2 steps */
> diff --git a/drivers/pci/of.c b/drivers/pci/of.c
> index 9f8eb5df279e..1f9b669abdb0 100644
> --- a/drivers/pci/of.c
> +++ b/drivers/pci/of.c
> @@ -38,7 +38,7 @@ int pci_set_of_node(struct pci_dev *dev)
>  	struct device *pdev __free(put_device) =
>  		bus_find_device_by_of_node(&platform_bus_type, node);
>  	if (pdev)
> -		dev->bus->dev.of_node_reused = true;
> +		dev_set_of_node_reused(&dev->bus->dev);
>  
>  	device_set_node(&dev->dev, of_fwnode_handle(no_free_ptr(node)));
>  	return 0;
> diff --git a/drivers/pci/pwrctrl/core.c b/drivers/pci/pwrctrl/core.c
> index 7754baed67f2..72963a92362a 100644
> --- a/drivers/pci/pwrctrl/core.c
> +++ b/drivers/pci/pwrctrl/core.c
> @@ -39,7 +39,7 @@ static int pci_pwrctrl_notify(struct notifier_block *nb, unsigned long action,
>  		 * If we got here then the PCI device is the second after the
>  		 * power control platform device. Mark its OF node as reused.
>  		 */
> -		dev->of_node_reused = true;
> +		dev_set_of_node_reused(dev);
>  		break;
>  	}
>  
> diff --git a/drivers/regulator/bq257xx-regulator.c b/drivers/regulator/bq257xx-regulator.c
> index dab8f1ab4450..40e0f1a7ae81 100644
> --- a/drivers/regulator/bq257xx-regulator.c
> +++ b/drivers/regulator/bq257xx-regulator.c
> @@ -143,7 +143,7 @@ static int bq257xx_regulator_probe(struct platform_device *pdev)
>  	struct regulator_config cfg = {};
>  
>  	pdev->dev.of_node = pdev->dev.parent->of_node;
> -	pdev->dev.of_node_reused = true;
> +	dev_set_of_node_reused(&pdev->dev);
>  
>  	pdata = devm_kzalloc(&pdev->dev, sizeof(struct bq257xx_reg_data), GFP_KERNEL);
>  	if (!pdata)
> diff --git a/drivers/regulator/rk808-regulator.c b/drivers/regulator/rk808-regulator.c
> index e66408f23bb6..8297d31cde9f 100644
> --- a/drivers/regulator/rk808-regulator.c
> +++ b/drivers/regulator/rk808-regulator.c
> @@ -2115,7 +2115,7 @@ static int rk808_regulator_probe(struct platform_device *pdev)
>  	int ret, i, nregulators;
>  
>  	pdev->dev.of_node = pdev->dev.parent->of_node;
> -	pdev->dev.of_node_reused = true;
> +	dev_set_of_node_reused(&pdev->dev);
>  
>  	regmap = dev_get_regmap(pdev->dev.parent, NULL);
>  	if (!regmap)
> diff --git a/drivers/tty/serial/serial_base_bus.c b/drivers/tty/serial/serial_base_bus.c
> index a12935f6b992..5f23284a8778 100644
> --- a/drivers/tty/serial/serial_base_bus.c
> +++ b/drivers/tty/serial/serial_base_bus.c
> @@ -74,7 +74,7 @@ static int serial_base_device_init(struct uart_port *port,
>  	dev->parent = parent_dev;
>  	dev->bus = &serial_base_bus_type;
>  	dev->release = release;
> -	dev->of_node_reused = true;
> +	dev_set_of_node_reused(dev);
>  
>  	device_set_node(dev, fwnode_handle_get(dev_fwnode(parent_dev)));
>  
> diff --git a/drivers/usb/gadget/udc/aspeed-vhub/dev.c b/drivers/usb/gadget/udc/aspeed-vhub/dev.c
> index 2ecd049dacc2..8b9449d16324 100644
> --- a/drivers/usb/gadget/udc/aspeed-vhub/dev.c
> +++ b/drivers/usb/gadget/udc/aspeed-vhub/dev.c
> @@ -593,7 +593,7 @@ int ast_vhub_init_dev(struct ast_vhub *vhub, unsigned int idx)
>  		d->gadget.max_speed = USB_SPEED_HIGH;
>  	d->gadget.speed = USB_SPEED_UNKNOWN;
>  	d->gadget.dev.of_node = vhub->pdev->dev.of_node;
> -	d->gadget.dev.of_node_reused = true;
> +	dev_set_of_node_reused(&d->gadget.dev);
>  
>  	rc = usb_add_gadget_udc(d->port_dev, &d->gadget);
>  	if (rc != 0)
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 5b0fb6ad4c72..a79865a212e9 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -483,6 +483,8 @@ struct device_physical_location {
>   *		driver/bus sync_state() callback.
>   * @DEV_FLAG_DMA_COHERENT: This particular device is dma coherent, even if the
>   *		architecture supports non-coherent devices.
> + * @DEV_FLAG_OF_NODE_REUSED: Set if the device-tree node is shared with an
> + *		ancestor device.
>   */
>  enum struct_device_flags {
>  	DEV_FLAG_READY_TO_PROBE = 0,
> @@ -492,6 +494,7 @@ enum struct_device_flags {
>  	DEV_FLAG_DMA_OPS_BYPASS = 4,
>  	DEV_FLAG_STATE_SYNCED = 5,
>  	DEV_FLAG_DMA_COHERENT = 6,
> +	DEV_FLAG_OF_NODE_REUSED = 7,
>  
>  	DEV_FLAG_COUNT
>  };
> @@ -573,8 +576,6 @@ enum struct_device_flags {
>   *
>   * @offline_disabled: If set, the device is permanently online.
>   * @offline:	Set after successful invocation of bus type's .offline().
> - * @of_node_reused: Set if the device-tree node is shared with an ancestor
> - *              device.
>   * @flags:	DEV_FLAG_XXX flags. Use atomic bitfield operations to modify.
>   *
>   * At the lowest level, every device in a Linux system is represented by an
> @@ -681,7 +682,6 @@ struct device {
>  
>  	bool			offline_disabled:1;
>  	bool			offline:1;
> -	bool			of_node_reused:1;
>  
>  	DECLARE_BITMAP(flags, DEV_FLAG_COUNT);
>  };
> @@ -715,6 +715,7 @@ __create_dev_flag_accessors(dma_skip_sync, DEV_FLAG_DMA_SKIP_SYNC);
>  __create_dev_flag_accessors(dma_ops_bypass, DEV_FLAG_DMA_OPS_BYPASS);
>  __create_dev_flag_accessors(state_synced, DEV_FLAG_STATE_SYNCED);
>  __create_dev_flag_accessors(dma_coherent, DEV_FLAG_DMA_COHERENT);
> +__create_dev_flag_accessors(of_node_reused, DEV_FLAG_OF_NODE_REUSED);
>  
>  #undef __create_dev_flag_accessors
>  
> -- 
> 2.53.0.1213.gd9a14994de-goog
> 

-- 
மணிவண்ணன் சதாசிவம்

^ permalink raw reply

* Re: [PATCH v5 8/9] driver core: Replace dev->of_node_reused with dev_of_node_reused()
From: Johan Hovold @ 2026-04-07  9:07 UTC (permalink / raw)
  To: Douglas Anderson
  Cc: Greg Kroah-Hartman, Rafael J . Wysocki, Danilo Krummrich,
	Alan Stern, Alexey Kardashevskiy, Eric Dumazet, Leon Romanovsky,
	Christoph Hellwig, Robin Murphy, maz, Alexander Lobakin,
	Saravana Kannan, Mark Brown, alexander.stein, andrew, andrew,
	andriy.shevchenko, astewart, bhelgaas, brgl, davem, devicetree,
	driver-core, hkallweit1, jirislaby, joel, kees, kuba, lgirdwood,
	linux-arm-kernel, linux-aspeed, linux-kernel, linux-pci,
	linux-serial, linux-usb, linux, mani, netdev, pabeni, robh
In-Reply-To: <20260406162231.v5.8.I806b8636cd3724f6cd1f5e199318ab8694472d90@changeid>

On Mon, Apr 06, 2026 at 04:23:01PM -0700, Doug Anderson wrote:
> In C, bitfields are not necessarily safe to modify from multiple
> threads without locking. Switch "of_node_reused" over to the "flags"
> field so modifications are safe.

This flag is only set before registering a device with driver core so
there is no issue using the existing bitfield here (with the caveat that
PCI pwrctrl may have gotten that wrong). I haven't checked the other
flags, but I assume most of them work the same way.

But apart from the commit message being misleading, switching to using
atomic ops and accessors for consistency is fine.

> Cc: Johan Hovold <johan@kernel.org>
> Acked-by: Mark Brown <broonie@kernel.org>
> Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
> Reviewed-by: Danilo Krummrich <dakr@kernel.org>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---
> Not fixing any known bugs; problem is theoretical and found by code
> inspection. Change is done somewhat manually and only lightly tested
> (mostly compile-time tested).
 
> diff --git a/drivers/regulator/bq257xx-regulator.c b/drivers/regulator/bq257xx-regulator.c
> index dab8f1ab4450..40e0f1a7ae81 100644
> --- a/drivers/regulator/bq257xx-regulator.c
> +++ b/drivers/regulator/bq257xx-regulator.c
> @@ -143,7 +143,7 @@ static int bq257xx_regulator_probe(struct platform_device *pdev)
>  	struct regulator_config cfg = {};
>  
>  	pdev->dev.of_node = pdev->dev.parent->of_node;
> -	pdev->dev.of_node_reused = true;
> +	dev_set_of_node_reused(&pdev->dev);
>  
>  	pdata = devm_kzalloc(&pdev->dev, sizeof(struct bq257xx_reg_data), GFP_KERNEL);
>  	if (!pdata)
> diff --git a/drivers/regulator/rk808-regulator.c b/drivers/regulator/rk808-regulator.c
> index e66408f23bb6..8297d31cde9f 100644
> --- a/drivers/regulator/rk808-regulator.c
> +++ b/drivers/regulator/rk808-regulator.c
> @@ -2115,7 +2115,7 @@ static int rk808_regulator_probe(struct platform_device *pdev)
>  	int ret, i, nregulators;
>  
>  	pdev->dev.of_node = pdev->dev.parent->of_node;
> -	pdev->dev.of_node_reused = true;
> +	dev_set_of_node_reused(&pdev->dev);
>  
>  	regmap = dev_get_regmap(pdev->dev.parent, NULL);
>  	if (!regmap)

These two uses are broken currently though and should be using
device_set_of_node_from_dev() so that an extra reference is taken to
balance the one dropped by the platform bus code.

I'll send two fixes to Mark, any merge conflict should be trivial to
fixup.

Reviewed-by: Johan Hovold <johan@kernel.org>

Johan

^ permalink raw reply

* [PATCH v2 00/10] fbcon,fonts: Refactor framebuffer console rotation
From: Thomas Zimmermann @ 2026-04-07  9:23 UTC (permalink / raw)
  To: deller, gregkh, jirislaby, geert, simona, sam
  Cc: linux-fbdev, dri-devel, linux-kernel, linux-serial,
	Thomas Zimmermann

Refactor the framebuffer console rotation into individual components
for glyphs, fonts and the overall fbcon state. Right now this is mixed
up in fbcon_rotate.{c,h}. Also build cursor rotation on top of the new
interfaces.

Start with an OOB fix in patch 1. If buffer allocation fails, fbcon
currently uses a too-small glyph buffer for output. Avoid that.

Patches 2 to 4 make a number of small improvements to the font library
and its callers.

Patches 5 to 8 refactor the font rotation. Fbcon rotation rotates each
individual glyph in a font buffer and uses the rotated buffer's glyphs
for output. The result looks like the console buffer has been rotated
as a whole. Split this into helpers that rotate individual glyphs and
a helper that rotates the font buffer of these. Then reimplement fbcon
rotation on top. Document the public font helpers.

Patch 9 rebuilds cursor rotation on top of the new glyph helpers. The
fbcon cursor is itself a glyph that has to be rotated in sync with the
font.

Patch 10 moves all state of fbcon rotation into a single place and makes
it a build-time conditional.

Tested with fbcon under bochs on Qemu.

Built upon the fbcon changes at [1].

v2:
- fix sparse truncated-bits warning
- improve font sorting in Makefile
- fix typos

[1] https://lore.kernel.org/linux-fbdev/20260309141723.137364-1-tzimmermann@suse.de/

Thomas Zimmermann (10):
  fbcon: Avoid OOB font access if console rotation fails
  vt: Implement helpers for struct vc_font in source file
  lib/fonts: Provide helpers for calculating glyph pitch and size
  lib/fonts: Clean up Makefile
  lib/fonts: Implement glyph rotation
  lib/fonts: Refactor glyph-pattern helpers
  lib/fonts: Refactor glyph-rotation helpers
  lib/fonts: Implement font rotation
  fbcon: Fill cursor mask in helper function
  fbcon: Put font-rotation state into separate struct

 drivers/tty/vt/vt.c                     |  34 +++
 drivers/video/fbdev/core/bitblit.c      |  35 +--
 drivers/video/fbdev/core/fbcon.c        |  48 ++++-
 drivers/video/fbdev/core/fbcon.h        |  14 +-
 drivers/video/fbdev/core/fbcon_ccw.c    |  70 ++----
 drivers/video/fbdev/core/fbcon_cw.c     |  70 ++----
 drivers/video/fbdev/core/fbcon_rotate.c |  88 ++------
 drivers/video/fbdev/core/fbcon_rotate.h |  71 ------
 drivers/video/fbdev/core/fbcon_ud.c     |  67 ++----
 include/linux/console_struct.h          |  30 +--
 include/linux/font.h                    |  51 +++++
 lib/fonts/Makefile                      |  36 ++--
 lib/fonts/font_rotate.c                 | 275 ++++++++++++++++++++++++
 lib/fonts/fonts.c                       |   2 +-
 14 files changed, 525 insertions(+), 366 deletions(-)
 create mode 100644 lib/fonts/font_rotate.c

-- 
2.53.0


^ permalink raw reply

* [PATCH v2 05/10] lib/fonts: Implement glyph rotation
From: Thomas Zimmermann @ 2026-04-07  9:23 UTC (permalink / raw)
  To: deller, gregkh, jirislaby, geert, simona, sam
  Cc: linux-fbdev, dri-devel, linux-kernel, linux-serial,
	Thomas Zimmermann
In-Reply-To: <20260407092555.58816-1-tzimmermann@suse.de>

Move the glyph rotation helpers from fbcon to the font library. Wrap them
behind clean interfaces. Also clear the output memory to zero. Previously,
the implementation relied on the caller to do that.

Go through the fbcon code and callers of the glyph-rotation helpers. In
addition to the font rotation, there's also the cursor code, which uses
the rotation helpers.

The font-rotation relied on a single memset to zero for the whole font.
This is now multiple memsets on each glyph. This will be sorted out when
the font library also implements font rotation.

Building glyph rotation in the font library still depends on
CONFIG_FRAMEBUFFER_CONSOLE_ROTATION=y. If we get more users of the code,
we can still add a dedicated Kconfig symbol to the font library.

No changes have been made to the actual implementation of the rotate_*()
and pattern_*() functions. These will be refactored as separate changes.

v2:
- fix typos

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/fbdev/core/fbcon_ccw.c    |   4 +-
 drivers/video/fbdev/core/fbcon_cw.c     |   4 +-
 drivers/video/fbdev/core/fbcon_rotate.c |  12 +-
 drivers/video/fbdev/core/fbcon_rotate.h |  71 -----------
 include/linux/font.h                    |   8 ++
 lib/fonts/Makefile                      |   1 +
 lib/fonts/font_rotate.c                 | 150 ++++++++++++++++++++++++
 7 files changed, 167 insertions(+), 83 deletions(-)
 create mode 100644 lib/fonts/font_rotate.c

diff --git a/drivers/video/fbdev/core/fbcon_ccw.c b/drivers/video/fbdev/core/fbcon_ccw.c
index 96ef449ee6ac..72453a2aaca8 100644
--- a/drivers/video/fbdev/core/fbcon_ccw.c
+++ b/drivers/video/fbdev/core/fbcon_ccw.c
@@ -12,6 +12,7 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/fb.h>
+#include <linux/font.h>
 #include <linux/vt_kern.h>
 #include <linux/console.h>
 #include <asm/types.h>
@@ -344,8 +345,7 @@ static void ccw_cursor(struct vc_data *vc, struct fb_info *info, bool enable,
 		size = cur_height * width;
 		while (size--)
 			tmp[i++] = 0xff;
-		memset(mask, 0, w * vc->vc_font.width);
-		rotate_ccw(tmp, mask, vc->vc_font.width, vc->vc_font.height);
+		font_glyph_rotate_270(tmp, vc->vc_font.width, vc->vc_font.height, mask);
 		kfree(tmp);
 	}
 
diff --git a/drivers/video/fbdev/core/fbcon_cw.c b/drivers/video/fbdev/core/fbcon_cw.c
index ea712654edae..5690fc1d7854 100644
--- a/drivers/video/fbdev/core/fbcon_cw.c
+++ b/drivers/video/fbdev/core/fbcon_cw.c
@@ -12,6 +12,7 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/fb.h>
+#include <linux/font.h>
 #include <linux/vt_kern.h>
 #include <linux/console.h>
 #include <asm/types.h>
@@ -327,8 +328,7 @@ static void cw_cursor(struct vc_data *vc, struct fb_info *info, bool enable,
 		size = cur_height * width;
 		while (size--)
 			tmp[i++] = 0xff;
-		memset(mask, 0, w * vc->vc_font.width);
-		rotate_cw(tmp, mask, vc->vc_font.width, vc->vc_font.height);
+		font_glyph_rotate_90(tmp, vc->vc_font.width, vc->vc_font.height, mask);
 		kfree(tmp);
 	}
 
diff --git a/drivers/video/fbdev/core/fbcon_rotate.c b/drivers/video/fbdev/core/fbcon_rotate.c
index 18575c5182db..588dc9d6758a 100644
--- a/drivers/video/fbdev/core/fbcon_rotate.c
+++ b/drivers/video/fbdev/core/fbcon_rotate.c
@@ -12,6 +12,7 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/fb.h>
+#include <linux/font.h>
 #include <linux/vt_kern.h>
 #include <linux/console.h>
 #include <asm/types.h>
@@ -60,30 +61,25 @@ int fbcon_rotate_font(struct fb_info *info, struct vc_data *vc)
 	}
 
 	dst = par->fontbuffer;
-	memset(dst, 0, par->fd_size);
 
 	switch (par->rotate) {
 	case FB_ROTATE_UD:
 		for (i = len; i--; ) {
-			rotate_ud(src, dst, vc->vc_font.width,
-				  vc->vc_font.height);
-
+			font_glyph_rotate_180(src, vc->vc_font.width, vc->vc_font.height, dst);
 			src += s_cellsize;
 			dst += d_cellsize;
 		}
 		break;
 	case FB_ROTATE_CW:
 		for (i = len; i--; ) {
-			rotate_cw(src, dst, vc->vc_font.width,
-				  vc->vc_font.height);
+			font_glyph_rotate_90(src, vc->vc_font.width, vc->vc_font.height, dst);
 			src += s_cellsize;
 			dst += d_cellsize;
 		}
 		break;
 	case FB_ROTATE_CCW:
 		for (i = len; i--; ) {
-			rotate_ccw(src, dst, vc->vc_font.width,
-				   vc->vc_font.height);
+			font_glyph_rotate_270(src, vc->vc_font.width, vc->vc_font.height, dst);
 			src += s_cellsize;
 			dst += d_cellsize;
 		}
diff --git a/drivers/video/fbdev/core/fbcon_rotate.h b/drivers/video/fbdev/core/fbcon_rotate.h
index 8cb019e8a9c0..725bcae2df61 100644
--- a/drivers/video/fbdev/core/fbcon_rotate.h
+++ b/drivers/video/fbdev/core/fbcon_rotate.h
@@ -19,77 +19,6 @@
         (fb_scrollmode(s) == SCROLL_REDRAW || fb_scrollmode(s) == SCROLL_MOVE || !(i)->fix.xpanstep) ? \
         (i)->var.xres : (i)->var.xres_virtual; })
 
-
-static inline int pattern_test_bit(u32 x, u32 y, u32 pitch, const char *pat)
-{
-	u32 tmp = (y * pitch) + x, index = tmp / 8,  bit = tmp % 8;
-
-	pat +=index;
-	return (*pat) & (0x80 >> bit);
-}
-
-static inline void pattern_set_bit(u32 x, u32 y, u32 pitch, char *pat)
-{
-	u32 tmp = (y * pitch) + x, index = tmp / 8, bit = tmp % 8;
-
-	pat += index;
-
-	(*pat) |= 0x80 >> bit;
-}
-
-static inline void rotate_ud(const char *in, char *out, u32 width, u32 height)
-{
-	int i, j;
-	int shift = (8 - (width % 8)) & 7;
-
-	width = (width + 7) & ~7;
-
-	for (i = 0; i < height; i++) {
-		for (j = 0; j < width - shift; j++) {
-			if (pattern_test_bit(j, i, width, in))
-				pattern_set_bit(width - (1 + j + shift),
-						height - (1 + i),
-						width, out);
-		}
-
-	}
-}
-
-static inline void rotate_cw(const char *in, char *out, u32 width, u32 height)
-{
-	int i, j, h = height, w = width;
-	int shift = (8 - (height % 8)) & 7;
-
-	width = (width + 7) & ~7;
-	height = (height + 7) & ~7;
-
-	for (i = 0; i < h; i++) {
-		for (j = 0; j < w; j++) {
-			if (pattern_test_bit(j, i, width, in))
-				pattern_set_bit(height - 1 - i - shift, j,
-						height, out);
-
-		}
-	}
-}
-
-static inline void rotate_ccw(const char *in, char *out, u32 width, u32 height)
-{
-	int i, j, h = height, w = width;
-	int shift = (8 - (width % 8)) & 7;
-
-	width = (width + 7) & ~7;
-	height = (height + 7) & ~7;
-
-	for (i = 0; i < h; i++) {
-		for (j = 0; j < w; j++) {
-			if (pattern_test_bit(j, i, width, in))
-				pattern_set_bit(i, width - 1 - j - shift,
-						height, out);
-		}
-	}
-}
-
 int fbcon_rotate_font(struct fb_info *info, struct vc_data *vc);
 
 #if defined(CONFIG_FRAMEBUFFER_CONSOLE_ROTATION)
diff --git a/include/linux/font.h b/include/linux/font.h
index 3bd49d914b22..0a240dd70422 100644
--- a/include/linux/font.h
+++ b/include/linux/font.h
@@ -104,6 +104,14 @@ unsigned int font_data_size(font_data_t *fd);
 bool font_data_is_equal(font_data_t *lhs, font_data_t *rhs);
 int font_data_export(font_data_t *fd, struct console_font *font, unsigned int vpitch);
 
+/* font_rotate.c */
+void font_glyph_rotate_90(const unsigned char *glyph, unsigned int width, unsigned int height,
+			  unsigned char *out);
+void font_glyph_rotate_180(const unsigned char *glyph, unsigned int width, unsigned int height,
+			   unsigned char *out);
+void font_glyph_rotate_270(const unsigned char *glyph, unsigned int width, unsigned int height,
+			   unsigned char *out);
+
 /*
  * Font description
  */
diff --git a/lib/fonts/Makefile b/lib/fonts/Makefile
index b176af53d53e..7202a70a56ef 100644
--- a/lib/fonts/Makefile
+++ b/lib/fonts/Makefile
@@ -2,6 +2,7 @@
 # Font handling
 
 font-y := fonts.o
+font-$(CONFIG_FRAMEBUFFER_CONSOLE_ROTATION) += font_rotate.o
 
 # Built-in fonts; sorted by Family-Size in ascending order
 font-$(CONFIG_FONT_6x8)       += font_6x8.o
diff --git a/lib/fonts/font_rotate.c b/lib/fonts/font_rotate.c
new file mode 100644
index 000000000000..d107a8d0a2b0
--- /dev/null
+++ b/lib/fonts/font_rotate.c
@@ -0,0 +1,150 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Font rotation
+ *
+ *    Copyright (C) 2005 Antonino Daplas <adaplas @pol.net>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive for
+ * more details.
+ */
+
+#include <linux/export.h>
+#include <linux/math.h>
+#include <linux/string.h>
+
+#include "font.h"
+
+static inline int pattern_test_bit(u32 x, u32 y, u32 pitch, const char *pat)
+{
+	u32 tmp = (y * pitch) + x, index = tmp / 8,  bit = tmp % 8;
+
+	pat += index;
+	return (*pat) & (0x80 >> bit);
+}
+
+static inline void pattern_set_bit(u32 x, u32 y, u32 pitch, char *pat)
+{
+	u32 tmp = (y * pitch) + x, index = tmp / 8, bit = tmp % 8;
+
+	pat += index;
+
+	(*pat) |= 0x80 >> bit;
+}
+
+static inline void rotate_cw(const char *in, char *out, u32 width, u32 height)
+{
+	int i, j, h = height, w = width;
+	int shift = (8 - (height % 8)) & 7;
+
+	width = (width + 7) & ~7;
+	height = (height + 7) & ~7;
+
+	for (i = 0; i < h; i++) {
+		for (j = 0; j < w; j++) {
+			if (pattern_test_bit(j, i, width, in))
+				pattern_set_bit(height - 1 - i - shift, j,
+						height, out);
+		}
+	}
+}
+
+/**
+ * font_glyph_rotate_90 - Rotate a glyph pattern by 90° in clockwise direction
+ * @glyph: The glyph to rotate
+ * @width: The glyph width in bits per scanline
+ * @height: The number of scanlines in the glyph
+ * @out: The rotated glyph bitmap
+ *
+ * The parameters @width and @height refer to the input glyph given in @glyph.
+ * The caller has to provide the output buffer @out of sufficient size to hold
+ * the rotated glyph. Rotating by 90° flips the width and height for the output
+ * glyph. Depending on the glyph pitch, the size of the output glyph can be
+ * different than the size of the input. Callers have to take this into account
+ * when allocating the output memory.
+ */
+void font_glyph_rotate_90(const unsigned char *glyph, unsigned int width, unsigned int height,
+			  unsigned char *out)
+{
+	memset(out, 0, font_glyph_size(height, width)); /* flip width/height */
+
+	rotate_cw(glyph, out, width, height);
+}
+EXPORT_SYMBOL_GPL(font_glyph_rotate_90);
+
+static inline void rotate_ud(const char *in, char *out, u32 width, u32 height)
+{
+	int i, j;
+	int shift = (8 - (width % 8)) & 7;
+
+	width = (width + 7) & ~7;
+
+	for (i = 0; i < height; i++) {
+		for (j = 0; j < width - shift; j++) {
+			if (pattern_test_bit(j, i, width, in))
+				pattern_set_bit(width - (1 + j + shift),
+						height - (1 + i),
+						width, out);
+		}
+	}
+}
+
+/**
+ * font_glyph_rotate_180 - Rotate a glyph pattern by 180°
+ * @glyph: The glyph to rotate
+ * @width: The glyph width in bits per scanline
+ * @height: The number of scanlines in the glyph
+ * @out: The rotated glyph bitmap
+ *
+ * The parameters @width and @height refer to the input glyph given in @glyph.
+ * The caller has to provide the output buffer @out of sufficient size to hold
+ * the rotated glyph.
+ */
+void font_glyph_rotate_180(const unsigned char *glyph, unsigned int width, unsigned int height,
+			   unsigned char *out)
+{
+	memset(out, 0, font_glyph_size(width, height));
+
+	rotate_ud(glyph, out, width, height);
+}
+EXPORT_SYMBOL_GPL(font_glyph_rotate_180);
+
+static inline void rotate_ccw(const char *in, char *out, u32 width, u32 height)
+{
+	int i, j, h = height, w = width;
+	int shift = (8 - (width % 8)) & 7;
+
+	width = (width + 7) & ~7;
+	height = (height + 7) & ~7;
+
+	for (i = 0; i < h; i++) {
+		for (j = 0; j < w; j++) {
+			if (pattern_test_bit(j, i, width, in))
+				pattern_set_bit(i, width - 1 - j - shift,
+						height, out);
+		}
+	}
+}
+
+/**
+ * font_glyph_rotate_270 - Rotate a glyph pattern by 270° in clockwise direction
+ * @glyph: The glyph to rotate
+ * @width: The glyph width in bits per scanline
+ * @height: The number of scanlines in the glyph
+ * @out: The rotated glyph bitmap
+ *
+ * The parameters @width and @height refer to the input glyph given in @glyph.
+ * The caller has to provide the output buffer @out of sufficient size to hold
+ * the rotated glyph. Rotating by 270° flips the width and height for the output
+ * glyph. Depending on the glyph pitch, the size of the output glyph can be
+ * different than the size of the input. Callers have to take this into account
+ * when allocating the output memory.
+ */
+void font_glyph_rotate_270(const unsigned char *glyph, unsigned int width, unsigned int height,
+			   unsigned char *out)
+{
+	memset(out, 0, font_glyph_size(height, width)); /* flip width/height */
+
+	rotate_ccw(glyph, out, width, height);
+}
+EXPORT_SYMBOL_GPL(font_glyph_rotate_270);
-- 
2.53.0


^ permalink raw reply related

* [PATCH v2 01/10] fbcon: Avoid OOB font access if console rotation fails
From: Thomas Zimmermann @ 2026-04-07  9:23 UTC (permalink / raw)
  To: deller, gregkh, jirislaby, geert, simona, sam
  Cc: linux-fbdev, dri-devel, linux-kernel, linux-serial,
	Thomas Zimmermann, stable
In-Reply-To: <20260407092555.58816-1-tzimmermann@suse.de>

Clear the font buffer if the reallocation during console rotation fails
in fbcon_rotate_font(). The putcs implementations for the rotated buffer
will return early in this case. See [1] for an example.

Currently, fbcon_rotate_font() keeps the old buffer, which is too small
for the rotated font. Printing to the rotated console with a high-enough
character code will overflow the font buffer.

v2:
- fix typos in commit message

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 6cc50e1c5b57 ("[PATCH] fbcon: Console Rotation - Add support to rotate font bitmap")
Cc: <stable@vger.kernel.org> # v2.6.15+
Link: https://elixir.bootlin.com/linux/v6.19/source/drivers/video/fbdev/core/fbcon_ccw.c#L144 # [1]
---
 drivers/video/fbdev/core/fbcon_rotate.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/core/fbcon_rotate.c b/drivers/video/fbdev/core/fbcon_rotate.c
index 1562a8f20b4f..5348f6c6f57c 100644
--- a/drivers/video/fbdev/core/fbcon_rotate.c
+++ b/drivers/video/fbdev/core/fbcon_rotate.c
@@ -46,6 +46,10 @@ int fbcon_rotate_font(struct fb_info *info, struct vc_data *vc)
 		info->fbops->fb_sync(info);
 
 	if (par->fd_size < d_cellsize * len) {
+		kfree(par->fontbuffer);
+		par->fontbuffer = NULL;
+		par->fd_size = 0;
+
 		dst = kmalloc_array(len, d_cellsize, GFP_KERNEL);
 
 		if (dst == NULL) {
@@ -54,7 +58,6 @@ int fbcon_rotate_font(struct fb_info *info, struct vc_data *vc)
 		}
 
 		par->fd_size = d_cellsize * len;
-		kfree(par->fontbuffer);
 		par->fontbuffer = dst;
 	}
 
-- 
2.53.0


^ permalink raw reply related

* [PATCH v2 06/10] lib/fonts: Refactor glyph-pattern helpers
From: Thomas Zimmermann @ 2026-04-07  9:23 UTC (permalink / raw)
  To: deller, gregkh, jirislaby, geert, simona, sam
  Cc: linux-fbdev, dri-devel, linux-kernel, linux-serial,
	Thomas Zimmermann
In-Reply-To: <20260407092555.58816-1-tzimmermann@suse.de>

Change the signatures of the pattern helpers to align them with other
font-glyph helpers: use the font_glyph_ prefix and pass the glyph
buffer first.

Calculating the position of the involved bit is somewhat obfuscated
in the original implementation. Move it into the new helper
__font_glyph_pos() and use the result as array index and bit position.

Note that these bit helpers use a bit pitch, while other code uses a
byte pitch. This is intentional and required here.

v2:
- fix typos in commit message

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 lib/fonts/font_rotate.c | 45 ++++++++++++++++++++++++-----------------
 1 file changed, 27 insertions(+), 18 deletions(-)

diff --git a/lib/fonts/font_rotate.c b/lib/fonts/font_rotate.c
index d107a8d0a2b0..d79ec5eef712 100644
--- a/lib/fonts/font_rotate.c
+++ b/lib/fonts/font_rotate.c
@@ -15,21 +15,33 @@
 
 #include "font.h"
 
-static inline int pattern_test_bit(u32 x, u32 y, u32 pitch, const char *pat)
+static unsigned int __font_glyph_pos(unsigned int x, unsigned int y, unsigned int bit_pitch,
+				     unsigned int *bit)
 {
-	u32 tmp = (y * pitch) + x, index = tmp / 8,  bit = tmp % 8;
+	unsigned int off = y * bit_pitch + x;
+	unsigned int bit_shift = off % 8;
 
-	pat += index;
-	return (*pat) & (0x80 >> bit);
+	*bit = 0x80 >> bit_shift; /* MSB has position 0, LSB has position 7 */
+
+	return off / 8;
 }
 
-static inline void pattern_set_bit(u32 x, u32 y, u32 pitch, char *pat)
+static bool font_glyph_test_bit(const unsigned char *glyph, unsigned int x, unsigned int y,
+				unsigned int bit_pitch)
 {
-	u32 tmp = (y * pitch) + x, index = tmp / 8, bit = tmp % 8;
+	unsigned int bit;
+	unsigned int i = __font_glyph_pos(x, y, bit_pitch, &bit);
+
+	return glyph[i] & bit;
+}
 
-	pat += index;
+static void font_glyph_set_bit(unsigned char *glyph, unsigned int x, unsigned int y,
+			       unsigned int bit_pitch)
+{
+	unsigned int bit;
+	unsigned int i = __font_glyph_pos(x, y, bit_pitch, &bit);
 
-	(*pat) |= 0x80 >> bit;
+	glyph[i] |= bit;
 }
 
 static inline void rotate_cw(const char *in, char *out, u32 width, u32 height)
@@ -42,9 +54,8 @@ static inline void rotate_cw(const char *in, char *out, u32 width, u32 height)
 
 	for (i = 0; i < h; i++) {
 		for (j = 0; j < w; j++) {
-			if (pattern_test_bit(j, i, width, in))
-				pattern_set_bit(height - 1 - i - shift, j,
-						height, out);
+			if (font_glyph_test_bit(in, j, i, width))
+				font_glyph_set_bit(out, height - 1 - i - shift, j, height);
 		}
 	}
 }
@@ -81,10 +92,9 @@ static inline void rotate_ud(const char *in, char *out, u32 width, u32 height)
 
 	for (i = 0; i < height; i++) {
 		for (j = 0; j < width - shift; j++) {
-			if (pattern_test_bit(j, i, width, in))
-				pattern_set_bit(width - (1 + j + shift),
-						height - (1 + i),
-						width, out);
+			if (font_glyph_test_bit(in, j, i, width))
+				font_glyph_set_bit(out, width - (1 + j + shift),
+						   height - (1 + i), width);
 		}
 	}
 }
@@ -119,9 +129,8 @@ static inline void rotate_ccw(const char *in, char *out, u32 width, u32 height)
 
 	for (i = 0; i < h; i++) {
 		for (j = 0; j < w; j++) {
-			if (pattern_test_bit(j, i, width, in))
-				pattern_set_bit(i, width - 1 - j - shift,
-						height, out);
+			if (font_glyph_test_bit(in, j, i, width))
+				font_glyph_set_bit(out, i, width - 1 - j - shift, height);
 		}
 	}
 }
-- 
2.53.0


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