[PATCH v8] usb: dwc3: debugfs: Prevent any register access when devices is runtime suspended

[PATCH v8] usb: dwc3: debugfs: Prevent any register access when devices is runtime suspended

[Udipto Goswami]

When the dwc3 device is runtime suspended, various required clocks would
get disabled and it is not guaranteed that access to any registers would
work. Depending on the SoC glue, a register read could be as benign as
returning 0 or be fatal enough to hang the system.

In order to prevent such scenarios of fatal errors, make sure to resume
dwc3 then allow the function to proceed.

Signed-off-by: Udipto Goswami <quic_ugoswami@quicinc.com>
---
v8: Replace pm_runtime_get_sync with pm_runtime_resume_and get.
v7: Replaced pm_runtime_put with pm_runtime_put_sync & returned proper values.
v6: Added changes to handle get_dync failure appropriately.
v5: Reworked the patch to resume dwc3 while accessing the registers.
v4: Introduced pm_runtime_get_if_in_use in order to make sure dwc3 isn't
	suspended while accessing the registers.
v3: Replace pr_err to dev_err. 
v2: Replaced return 0 with -EINVAL & seq_puts with pr_err.

 drivers/usb/dwc3/debugfs.c | 99 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 97 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/debugfs.c b/drivers/usb/dwc3/debugfs.c
index e4a2560b9dc0..a996e3580150 100644
--- a/drivers/usb/dwc3/debugfs.c
+++ b/drivers/usb/dwc3/debugfs.c
@@ -332,6 +332,11 @@ static int dwc3_lsp_show(struct seq_file *s, void *unused)
 	unsigned int		current_mode;
 	unsigned long		flags;
 	u32			reg;
+	int			ret;
+
+	ret = pm_runtime_resume_and_get(dwc->dev);
+	if (ret < 0)
+		return ret;
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	reg = dwc3_readl(dwc->regs, DWC3_GSTS);
@@ -349,6 +354,7 @@ static int dwc3_lsp_show(struct seq_file *s, void *unused)
 		break;
 	}
 	spin_unlock_irqrestore(&dwc->lock, flags);
+	pm_runtime_put_sync(dwc->dev);
 
 	return 0;
 }
@@ -395,6 +401,11 @@ static int dwc3_mode_show(struct seq_file *s, void *unused)
 	struct dwc3		*dwc = s->private;
 	unsigned long		flags;
 	u32			reg;
+	int			ret;
+
+	ret = pm_runtime_resume_and_get(dwc->dev);
+	if (ret < 0)
+		return ret;
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
@@ -414,6 +425,7 @@ static int dwc3_mode_show(struct seq_file *s, void *unused)
 		seq_printf(s, "UNKNOWN %08x\n", DWC3_GCTL_PRTCAP(reg));
 	}
 
+	pm_runtime_put_sync(dwc->dev);
 	return 0;
 }
 
@@ -463,6 +475,11 @@ static int dwc3_testmode_show(struct seq_file *s, void *unused)
 	struct dwc3		*dwc = s->private;
 	unsigned long		flags;
 	u32			reg;
+	int			ret;
+
+	ret = pm_runtime_resume_and_get(dwc->dev);
+	if (ret < 0)
+		return ret;
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
@@ -493,6 +510,7 @@ static int dwc3_testmode_show(struct seq_file *s, void *unused)
 		seq_printf(s, "UNKNOWN %d\n", reg);
 	}
 
+	pm_runtime_put_sync(dwc->dev);
 	return 0;
 }
 
@@ -509,6 +527,7 @@ static ssize_t dwc3_testmode_write(struct file *file,
 	unsigned long		flags;
 	u32			testmode = 0;
 	char			buf[32];
+	int			ret;
 
 	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
 		return -EFAULT;
@@ -526,10 +545,15 @@ static ssize_t dwc3_testmode_write(struct file *file,
 	else
 		testmode = 0;
 
+	ret = pm_runtime_resume_and_get(dwc->dev);
+	if (ret < 0)
+		return ret;
+
 	spin_lock_irqsave(&dwc->lock, flags);
 	dwc3_gadget_set_test_mode(dwc, testmode);
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
+	pm_runtime_put_sync(dwc->dev);
 	return count;
 }
 
@@ -548,12 +572,18 @@ static int dwc3_link_state_show(struct seq_file *s, void *unused)
 	enum dwc3_link_state	state;
 	u32			reg;
 	u8			speed;
+	int			ret;
+
+	ret = pm_runtime_resume_and_get(dwc->dev);
+	if (ret < 0)
+		return ret;
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	reg = dwc3_readl(dwc->regs, DWC3_GSTS);
 	if (DWC3_GSTS_CURMOD(reg) != DWC3_GSTS_CURMOD_DEVICE) {
 		seq_puts(s, "Not available\n");
 		spin_unlock_irqrestore(&dwc->lock, flags);
+		pm_runtime_put_sync(dwc->dev);
 		return 0;
 	}
 
@@ -566,6 +596,7 @@ static int dwc3_link_state_show(struct seq_file *s, void *unused)
 		   dwc3_gadget_hs_link_string(state));
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
+	pm_runtime_put_sync(dwc->dev);
 	return 0;
 }
 
@@ -584,6 +615,7 @@ static ssize_t dwc3_link_state_write(struct file *file,
 	char			buf[32];
 	u32			reg;
 	u8			speed;
+	int			ret;
 
 	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
 		return -EFAULT;
@@ -603,11 +635,16 @@ static ssize_t dwc3_link_state_write(struct file *file,
 	else
 		return -EINVAL;
 
+	ret = pm_runtime_resume_and_get(dwc->dev);
+	if (ret < 0)
+		return ret;
+
 	spin_lock_irqsave(&dwc->lock, flags);
 	reg = dwc3_readl(dwc->regs, DWC3_GSTS);
 	if (DWC3_GSTS_CURMOD(reg) != DWC3_GSTS_CURMOD_DEVICE) {
 		spin_unlock_irqrestore(&dwc->lock, flags);
-		return -EINVAL;
+		pm_runtime_put_sync(dwc->dev);
+		return ret;
 	}
 
 	reg = dwc3_readl(dwc->regs, DWC3_DSTS);
@@ -616,12 +653,14 @@ static ssize_t dwc3_link_state_write(struct file *file,
 	if (speed < DWC3_DSTS_SUPERSPEED &&
 	    state != DWC3_LINK_STATE_RECOV) {
 		spin_unlock_irqrestore(&dwc->lock, flags);
-		return -EINVAL;
+		pm_runtime_put_sync(dwc->dev);
+		return ret;
 	}
 
 	dwc3_gadget_set_link_state(dwc, state);
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
+	pm_runtime_put_sync(dwc->dev);
 	return count;
 }
 
@@ -645,6 +684,11 @@ static int dwc3_tx_fifo_size_show(struct seq_file *s, void *unused)
 	unsigned long		flags;
 	u32			mdwidth;
 	u32			val;
+	int			ret;
+
+	ret = pm_runtime_resume_and_get(dwc->dev);
+	if (ret < 0)
+		return ret;
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	val = dwc3_core_fifo_space(dep, DWC3_TXFIFO);
@@ -657,6 +701,7 @@ static int dwc3_tx_fifo_size_show(struct seq_file *s, void *unused)
 	seq_printf(s, "%u\n", val);
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
+	pm_runtime_put_sync(dwc->dev);
 	return 0;
 }
 
@@ -667,6 +712,12 @@ static int dwc3_rx_fifo_size_show(struct seq_file *s, void *unused)
 	unsigned long		flags;
 	u32			mdwidth;
 	u32			val;
+	int			ret;
+
+	ret = pm_runtime_resume_and_get(dwc->dev);
+	if (ret < 0)
+		pm_runtime_put_sync(dwc->dev);
+		return ret;
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	val = dwc3_core_fifo_space(dep, DWC3_RXFIFO);
@@ -679,6 +730,7 @@ static int dwc3_rx_fifo_size_show(struct seq_file *s, void *unused)
 	seq_printf(s, "%u\n", val);
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
+	pm_runtime_put_sync(dwc->dev);
 	return 0;
 }
 
@@ -688,12 +740,18 @@ static int dwc3_tx_request_queue_show(struct seq_file *s, void *unused)
 	struct dwc3		*dwc = dep->dwc;
 	unsigned long		flags;
 	u32			val;
+	int			ret;
+
+	ret = pm_runtime_resume_and_get(dwc->dev);
+	if (ret < 0)
+		return ret;
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	val = dwc3_core_fifo_space(dep, DWC3_TXREQQ);
 	seq_printf(s, "%u\n", val);
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
+	pm_runtime_put_sync(dwc->dev);
 	return 0;
 }
 
@@ -703,12 +761,18 @@ static int dwc3_rx_request_queue_show(struct seq_file *s, void *unused)
 	struct dwc3		*dwc = dep->dwc;
 	unsigned long		flags;
 	u32			val;
+	int			ret;
+
+	ret = pm_runtime_resume_and_get(dwc->dev);
+	if (ret < 0)
+		return ret;
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	val = dwc3_core_fifo_space(dep, DWC3_RXREQQ);
 	seq_printf(s, "%u\n", val);
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
+	pm_runtime_put_sync(dwc->dev);
 	return 0;
 }
 
@@ -718,12 +782,18 @@ static int dwc3_rx_info_queue_show(struct seq_file *s, void *unused)
 	struct dwc3		*dwc = dep->dwc;
 	unsigned long		flags;
 	u32			val;
+	int			ret;
+
+	ret = pm_runtime_resume_and_get(dwc->dev);
+	if (ret < 0)
+		return ret;
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	val = dwc3_core_fifo_space(dep, DWC3_RXINFOQ);
 	seq_printf(s, "%u\n", val);
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
+	pm_runtime_put_sync(dwc->dev);
 	return 0;
 }
 
@@ -733,12 +803,18 @@ static int dwc3_descriptor_fetch_queue_show(struct seq_file *s, void *unused)
 	struct dwc3		*dwc = dep->dwc;
 	unsigned long		flags;
 	u32			val;
+	int			ret;
+
+	ret = pm_runtime_resume_and_get(dwc->dev);
+	if (ret < 0)
+		return ret;
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	val = dwc3_core_fifo_space(dep, DWC3_DESCFETCHQ);
 	seq_printf(s, "%u\n", val);
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
+	pm_runtime_put_sync(dwc->dev);
 	return 0;
 }
 
@@ -748,12 +824,18 @@ static int dwc3_event_queue_show(struct seq_file *s, void *unused)
 	struct dwc3		*dwc = dep->dwc;
 	unsigned long		flags;
 	u32			val;
+	int			ret;
+
+	ret = pm_runtime_resume_and_get(dwc->dev);
+	if (ret < 0)
+		return ret;
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	val = dwc3_core_fifo_space(dep, DWC3_EVENTQ);
 	seq_printf(s, "%u\n", val);
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
+	pm_runtime_put_sync(dwc->dev);
 	return 0;
 }
 
@@ -798,6 +880,11 @@ static int dwc3_trb_ring_show(struct seq_file *s, void *unused)
 	struct dwc3		*dwc = dep->dwc;
 	unsigned long		flags;
 	int			i;
+	int			ret;
+
+	ret = pm_runtime_resume_and_get(dwc->dev);
+	if (ret < 0)
+		return ret;
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	if (dep->number <= 1) {
@@ -827,6 +914,7 @@ static int dwc3_trb_ring_show(struct seq_file *s, void *unused)
 out:
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
+	pm_runtime_put_sync(dwc->dev);
 	return 0;
 }
 
@@ -839,6 +927,11 @@ static int dwc3_ep_info_register_show(struct seq_file *s, void *unused)
 	u32			lower_32_bits;
 	u32			upper_32_bits;
 	u32			reg;
+	int			ret;
+
+	ret = pm_runtime_resume_and_get(dwc->dev);
+	if (ret < 0)
+		return ret;
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	reg = DWC3_GDBGLSPMUX_EPSELECT(dep->number);
@@ -851,6 +944,7 @@ static int dwc3_ep_info_register_show(struct seq_file *s, void *unused)
 	seq_printf(s, "0x%016llx\n", ep_info);
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
+	pm_runtime_put_sync(dwc->dev);
 	return 0;
 }
 
@@ -910,6 +1004,7 @@ void dwc3_debugfs_init(struct dwc3 *dwc)
 	dwc->regset->regs = dwc3_regs;
 	dwc->regset->nregs = ARRAY_SIZE(dwc3_regs);
 	dwc->regset->base = dwc->regs - DWC3_GLOBALS_REGS_START;
+	dwc->regset->dev = dwc->dev;
 
 	root = debugfs_create_dir(dev_name(dwc->dev), usb_debug_root);
 	dwc->debug_root = root;
-- 
2.17.1

Re: [PATCH v8] usb: dwc3: debugfs: Prevent any register access when devices is runtime suspended

[kernel test robot]

Hi Udipto,

kernel test robot noticed the following build warnings:

[auto build test WARNING on usb/usb-testing]
[also build test WARNING on usb/usb-next usb/usb-linus driver-core/driver-core-testing driver-core/driver-core-next driver-core/driver-core-linus johan-usb-serial/usb-next johan-usb-serial/usb-linus linus/master v6.3 next-20230428]
[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/Udipto-Goswami/usb-dwc3-debugfs-Prevent-any-register-access-when-devices-is-runtime-suspended/20230504-125225
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
patch link:    https://lore.kernel.org/r/20230504045052.22347-1-quic_ugoswami%40quicinc.com
patch subject: [PATCH v8] usb: dwc3: debugfs: Prevent any register access when devices is runtime suspended
config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20230504/202305041526.hBiM1g2W-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/1c53edaeee33380f0fc3e0d262829ffaa66f45e1
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Udipto-Goswami/usb-dwc3-debugfs-Prevent-any-register-access-when-devices-is-runtime-suspended/20230504-125225
        git checkout 1c53edaeee33380f0fc3e0d262829ffaa66f45e1
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k SHELL=/bin/bash drivers/usb/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202305041526.hBiM1g2W-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/usb/dwc3/debugfs.c: In function 'dwc3_rx_fifo_size_show':
>> drivers/usb/dwc3/debugfs.c:718:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
     718 |         if (ret < 0)
         |         ^~
   drivers/usb/dwc3/debugfs.c:720:17: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
     720 |                 return ret;
         |                 ^~~~~~


vim +/if +718 drivers/usb/dwc3/debugfs.c

   707	
   708	static int dwc3_rx_fifo_size_show(struct seq_file *s, void *unused)
   709	{
   710		struct dwc3_ep		*dep = s->private;
   711		struct dwc3		*dwc = dep->dwc;
   712		unsigned long		flags;
   713		u32			mdwidth;
   714		u32			val;
   715		int			ret;
   716	
   717		ret = pm_runtime_resume_and_get(dwc->dev);
 > 718		if (ret < 0)
   719			pm_runtime_put_sync(dwc->dev);
   720			return ret;
   721	
   722		spin_lock_irqsave(&dwc->lock, flags);
   723		val = dwc3_core_fifo_space(dep, DWC3_RXFIFO);
   724	
   725		/* Convert to bytes */
   726		mdwidth = dwc3_mdwidth(dwc);
   727	
   728		val *= mdwidth;
   729		val >>= 3;
   730		seq_printf(s, "%u\n", val);
   731		spin_unlock_irqrestore(&dwc->lock, flags);
   732	
   733		pm_runtime_put_sync(dwc->dev);
   734		return 0;
   735	}
   736	

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

Re: [PATCH v8] usb: dwc3: debugfs: Prevent any register access when devices is runtime suspended

[Johan Hovold]

Please use a more succinct Subject. The current one is over 80 chars
which generally too long. Please also check the grammar (e.g. "devices
is") and make sure that the subject reflects what your patch does (and
not what it did in v1).

On Thu, May 04, 2023 at 10:20:52AM +0530, Udipto Goswami wrote:
> When the dwc3 device is runtime suspended, various required clocks would
> get disabled and it is not guaranteed that access to any registers would
> work. Depending on the SoC glue, a register read could be as benign as
> returning 0 or be fatal enough to hang the system.
> 
> In order to prevent such scenarios of fatal errors, make sure to resume
> dwc3 then allow the function to proceed.

As this fixes a crash/hang you should also add a Fixes and CC-stable
tag.

> Signed-off-by: Udipto Goswami <quic_ugoswami@quicinc.com>
> ---
> v8: Replace pm_runtime_get_sync with pm_runtime_resume_and get.
> v7: Replaced pm_runtime_put with pm_runtime_put_sync & returned proper values.
> v6: Added changes to handle get_dync failure appropriately.
> v5: Reworked the patch to resume dwc3 while accessing the registers.
> v4: Introduced pm_runtime_get_if_in_use in order to make sure dwc3 isn't
> 	suspended while accessing the registers.
> v3: Replace pr_err to dev_err. 
> v2: Replaced return 0 with -EINVAL & seq_puts with pr_err.
> 
>  drivers/usb/dwc3/debugfs.c | 99 +++++++++++++++++++++++++++++++++++++-
>  1 file changed, 97 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/debugfs.c b/drivers/usb/dwc3/debugfs.c
> index e4a2560b9dc0..a996e3580150 100644
> --- a/drivers/usb/dwc3/debugfs.c
> +++ b/drivers/usb/dwc3/debugfs.c
> @@ -332,6 +332,11 @@ static int dwc3_lsp_show(struct seq_file *s, void *unused)
>  	unsigned int		current_mode;
>  	unsigned long		flags;
>  	u32			reg;
> +	int			ret;
> +
> +	ret = pm_runtime_resume_and_get(dwc->dev);
> +	if (ret < 0)
> +		return ret;
>  
>  	spin_lock_irqsave(&dwc->lock, flags);
>  	reg = dwc3_readl(dwc->regs, DWC3_GSTS);
> @@ -349,6 +354,7 @@ static int dwc3_lsp_show(struct seq_file *s, void *unused)
>  		break;
>  	}
>  	spin_unlock_irqrestore(&dwc->lock, flags);

Add a newline here for symmetry.

> +	pm_runtime_put_sync(dwc->dev);
>  
>  	return 0;
>  }
> @@ -395,6 +401,11 @@ static int dwc3_mode_show(struct seq_file *s, void *unused)
>  	struct dwc3		*dwc = s->private;
>  	unsigned long		flags;
>  	u32			reg;
> +	int			ret;
> +
> +	ret = pm_runtime_resume_and_get(dwc->dev);
> +	if (ret < 0)
> +		return ret;
>  
>  	spin_lock_irqsave(&dwc->lock, flags);
>  	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
> @@ -414,6 +425,7 @@ static int dwc3_mode_show(struct seq_file *s, void *unused)
>  		seq_printf(s, "UNKNOWN %08x\n", DWC3_GCTL_PRTCAP(reg));
>  	}
>  
> +	pm_runtime_put_sync(dwc->dev);

For consistency and readability, add a newline here before the return
statement. Same below.

>  	return 0;
>  }
>  
 
> @@ -584,6 +615,7 @@ static ssize_t dwc3_link_state_write(struct file *file,
>  	char			buf[32];
>  	u32			reg;
>  	u8			speed;
> +	int			ret;
>  
>  	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
>  		return -EFAULT;
> @@ -603,11 +635,16 @@ static ssize_t dwc3_link_state_write(struct file *file,
>  	else
>  		return -EINVAL;
>  
> +	ret = pm_runtime_resume_and_get(dwc->dev);
> +	if (ret < 0)
> +		return ret;
> +
>  	spin_lock_irqsave(&dwc->lock, flags);
>  	reg = dwc3_readl(dwc->regs, DWC3_GSTS);
>  	if (DWC3_GSTS_CURMOD(reg) != DWC3_GSTS_CURMOD_DEVICE) {
>  		spin_unlock_irqrestore(&dwc->lock, flags);
> -		return -EINVAL;
> +		pm_runtime_put_sync(dwc->dev);
> +		return ret;

Why are you changing the return value here? That's simply wrong.

>  	}
>  
>  	reg = dwc3_readl(dwc->regs, DWC3_DSTS);
> @@ -616,12 +653,14 @@ static ssize_t dwc3_link_state_write(struct file *file,
>  	if (speed < DWC3_DSTS_SUPERSPEED &&
>  	    state != DWC3_LINK_STATE_RECOV) {
>  		spin_unlock_irqrestore(&dwc->lock, flags);
> -		return -EINVAL;
> +		pm_runtime_put_sync(dwc->dev);
> +		return ret;

Same here.

>  	}
>  
>  	dwc3_gadget_set_link_state(dwc, state);
>  	spin_unlock_irqrestore(&dwc->lock, flags);
>  
> +	pm_runtime_put_sync(dwc->dev);
>  	return count;
>  }
>  
 
> @@ -667,6 +712,12 @@ static int dwc3_rx_fifo_size_show(struct seq_file *s, void *unused)
>  	unsigned long		flags;
>  	u32			mdwidth;
>  	u32			val;
> +	int			ret;
> +
> +	ret = pm_runtime_resume_and_get(dwc->dev);
> +	if (ret < 0)
> +		pm_runtime_put_sync(dwc->dev);
> +		return ret;

As the build bot reported, you forgot to remove pm_runtime_put_sync()
here which means that you just broke this function which now always
returns some random stack data.

>  
>  	spin_lock_irqsave(&dwc->lock, flags);
>  	val = dwc3_core_fifo_space(dep, DWC3_RXFIFO);
> @@ -679,6 +730,7 @@ static int dwc3_rx_fifo_size_show(struct seq_file *s, void *unused)
>  	seq_printf(s, "%u\n", val);
>  	spin_unlock_irqrestore(&dwc->lock, flags);
>  
> +	pm_runtime_put_sync(dwc->dev);
>  	return 0;
>  }

Johan

Re: [PATCH v8] usb: dwc3: debugfs: Prevent any register access when devices is runtime suspended

[kernel test robot]

Hi Udipto,

kernel test robot noticed the following build warnings:

[auto build test WARNING on usb/usb-testing]
[also build test WARNING on usb/usb-next usb/usb-linus driver-core/driver-core-testing driver-core/driver-core-next driver-core/driver-core-linus johan-usb-serial/usb-next johan-usb-serial/usb-linus linus/master v6.4-rc1 next-20230509]
[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/Udipto-Goswami/usb-dwc3-debugfs-Prevent-any-register-access-when-devices-is-runtime-suspended/20230504-125225
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
patch link:    https://lore.kernel.org/r/20230504045052.22347-1-quic_ugoswami%40quicinc.com
patch subject: [PATCH v8] usb: dwc3: debugfs: Prevent any register access when devices is runtime suspended
config: hexagon-randconfig-r024-20230509 (https://download.01.org/0day-ci/archive/20230510/202305100533.3s1xdH64-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project b0fb98227c90adf2536c9ad644a74d5e92961111)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/1c53edaeee33380f0fc3e0d262829ffaa66f45e1
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Udipto-Goswami/usb-dwc3-debugfs-Prevent-any-register-access-when-devices-is-runtime-suspended/20230504-125225
        git checkout 1c53edaeee33380f0fc3e0d262829ffaa66f45e1
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash drivers/usb/dwc3/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202305100533.3s1xdH64-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from drivers/usb/dwc3/debugfs.c:23:
   In file included from drivers/usb/dwc3/core.h:20:
   In file included from include/linux/dma-mapping.h:10:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __raw_readb(PCI_IOBASE + addr);
                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
   #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
                                                     ^
   In file included from drivers/usb/dwc3/debugfs.c:23:
   In file included from drivers/usb/dwc3/core.h:20:
   In file included from include/linux/dma-mapping.h:10:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
                                                     ^
   In file included from drivers/usb/dwc3/debugfs.c:23:
   In file included from drivers/usb/dwc3/core.h:20:
   In file included from include/linux/dma-mapping.h:10:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writeb(value, PCI_IOBASE + addr);
                               ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
>> drivers/usb/dwc3/debugfs.c:720:3: warning: misleading indentation; statement is not part of the previous 'if' [-Wmisleading-indentation]
                   return ret;
                   ^
   drivers/usb/dwc3/debugfs.c:718:2: note: previous statement is here
           if (ret < 0)
           ^
   7 warnings generated.


vim +/if +720 drivers/usb/dwc3/debugfs.c

   707	
   708	static int dwc3_rx_fifo_size_show(struct seq_file *s, void *unused)
   709	{
   710		struct dwc3_ep		*dep = s->private;
   711		struct dwc3		*dwc = dep->dwc;
   712		unsigned long		flags;
   713		u32			mdwidth;
   714		u32			val;
   715		int			ret;
   716	
   717		ret = pm_runtime_resume_and_get(dwc->dev);
   718		if (ret < 0)
   719			pm_runtime_put_sync(dwc->dev);
 > 720			return ret;
   721	
   722		spin_lock_irqsave(&dwc->lock, flags);
   723		val = dwc3_core_fifo_space(dep, DWC3_RXFIFO);
   724	
   725		/* Convert to bytes */
   726		mdwidth = dwc3_mdwidth(dwc);
   727	
   728		val *= mdwidth;
   729		val >>= 3;
   730		seq_printf(s, "%u\n", val);
   731		spin_unlock_irqrestore(&dwc->lock, flags);
   732	
   733		pm_runtime_put_sync(dwc->dev);
   734		return 0;
   735	}
   736	

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

Re: [PATCH v8] usb: dwc3: debugfs: Prevent any register access when devices is runtime suspended

[Dan Carpenter]

Hi Udipto,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Udipto-Goswami/usb-dwc3-debugfs-Prevent-any-register-access-when-devices-is-runtime-suspended/20230504-125225
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
patch link:    https://lore.kernel.org/r/20230504045052.22347-1-quic_ugoswami%40quicinc.com
patch subject: [PATCH v8] usb: dwc3: debugfs: Prevent any register access when devices is runtime suspended
config: x86_64-randconfig-m001 (https://download.01.org/0day-ci/archive/20230510/202305101451.V2D0cM4S-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-12) 11.3.0

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Link: https://lore.kernel.org/r/202305101451.V2D0cM4S-lkp@intel.com/

New smatch warnings:
drivers/usb/dwc3/debugfs.c:647 dwc3_link_state_write() warn: missing error code? 'ret'
drivers/usb/dwc3/debugfs.c:720 dwc3_rx_fifo_size_show() warn: curly braces intended?
drivers/usb/dwc3/debugfs.c:722 dwc3_rx_fifo_size_show() warn: inconsistent indenting
drivers/usb/dwc3/debugfs.c:722 dwc3_rx_fifo_size_show() warn: ignoring unreachable code.

Old smatch warnings:
drivers/usb/dwc3/debugfs.c:657 dwc3_link_state_write() warn: missing error code? 'ret'

vim +/ret +647 drivers/usb/dwc3/debugfs.c

1c53edaeee3338 Udipto Goswami 2023-05-04  638  	ret = pm_runtime_resume_and_get(dwc->dev);
1c53edaeee3338 Udipto Goswami 2023-05-04  639  	if (ret < 0)
1c53edaeee3338 Udipto Goswami 2023-05-04  640  		return ret;
1c53edaeee3338 Udipto Goswami 2023-05-04  641  
138801aaa566ec Felipe Balbi   2012-01-02  642  	spin_lock_irqsave(&dwc->lock, flags);
d102444cac1564 Thinh Nguyen   2018-11-07  643  	reg = dwc3_readl(dwc->regs, DWC3_GSTS);
d102444cac1564 Thinh Nguyen   2018-11-07  644  	if (DWC3_GSTS_CURMOD(reg) != DWC3_GSTS_CURMOD_DEVICE) {
d102444cac1564 Thinh Nguyen   2018-11-07  645  		spin_unlock_irqrestore(&dwc->lock, flags);
1c53edaeee3338 Udipto Goswami 2023-05-04  646  		pm_runtime_put_sync(dwc->dev);
1c53edaeee3338 Udipto Goswami 2023-05-04 @647  		return ret;

ret is not necessarily an error code.

d102444cac1564 Thinh Nguyen   2018-11-07  648  	}
d102444cac1564 Thinh Nguyen   2018-11-07  649  
0d36dede457873 Thinh Nguyen   2018-11-07  650  	reg = dwc3_readl(dwc->regs, DWC3_DSTS);
0d36dede457873 Thinh Nguyen   2018-11-07  651  	speed = reg & DWC3_DSTS_CONNECTSPD;
0d36dede457873 Thinh Nguyen   2018-11-07  652  
0d36dede457873 Thinh Nguyen   2018-11-07  653  	if (speed < DWC3_DSTS_SUPERSPEED &&
0d36dede457873 Thinh Nguyen   2018-11-07  654  	    state != DWC3_LINK_STATE_RECOV) {
0d36dede457873 Thinh Nguyen   2018-11-07  655  		spin_unlock_irqrestore(&dwc->lock, flags);
1c53edaeee3338 Udipto Goswami 2023-05-04  656  		pm_runtime_put_sync(dwc->dev);
1c53edaeee3338 Udipto Goswami 2023-05-04  657  		return ret;
0d36dede457873 Thinh Nguyen   2018-11-07  658  	}

[ snip ]

2c85a1817e4ba0 Thinh Nguyen   2018-11-07  708  static int dwc3_rx_fifo_size_show(struct seq_file *s, void *unused)
818ec3aba883f5 Felipe Balbi   2016-04-14  709  {
818ec3aba883f5 Felipe Balbi   2016-04-14  710  	struct dwc3_ep		*dep = s->private;
818ec3aba883f5 Felipe Balbi   2016-04-14  711  	struct dwc3		*dwc = dep->dwc;
818ec3aba883f5 Felipe Balbi   2016-04-14  712  	unsigned long		flags;
d00be779cc5016 Thinh Nguyen   2021-03-27  713  	u32			mdwidth;
818ec3aba883f5 Felipe Balbi   2016-04-14  714  	u32			val;
1c53edaeee3338 Udipto Goswami 2023-05-04  715  	int			ret;
1c53edaeee3338 Udipto Goswami 2023-05-04  716  
1c53edaeee3338 Udipto Goswami 2023-05-04  717  	ret = pm_runtime_resume_and_get(dwc->dev);
1c53edaeee3338 Udipto Goswami 2023-05-04  718  	if (ret < 0)
1c53edaeee3338 Udipto Goswami 2023-05-04  719  		pm_runtime_put_sync(dwc->dev);
1c53edaeee3338 Udipto Goswami 2023-05-04 @720  		return ret;

Needs curly braces.

818ec3aba883f5 Felipe Balbi   2016-04-14  721  
818ec3aba883f5 Felipe Balbi   2016-04-14 @722  	spin_lock_irqsave(&dwc->lock, flags);
2c85a1817e4ba0 Thinh Nguyen   2018-11-07  723  	val = dwc3_core_fifo_space(dep, DWC3_RXFIFO);
0f874f79dc81ae Thinh Nguyen   2018-11-07  724  
0f874f79dc81ae Thinh Nguyen   2018-11-07  725  	/* Convert to bytes */
d00be779cc5016 Thinh Nguyen   2021-03-27  726  	mdwidth = dwc3_mdwidth(dwc);
4244ba02edb850 Thinh Nguyen   2020-04-11  727  
4244ba02edb850 Thinh Nguyen   2020-04-11  728  	val *= mdwidth;
0f874f79dc81ae Thinh Nguyen   2018-11-07  729  	val >>= 3;
818ec3aba883f5 Felipe Balbi   2016-04-14  730  	seq_printf(s, "%u\n", val);
818ec3aba883f5 Felipe Balbi   2016-04-14  731  	spin_unlock_irqrestore(&dwc->lock, flags);
818ec3aba883f5 Felipe Balbi   2016-04-14  732  
1c53edaeee3338 Udipto Goswami 2023-05-04  733  	pm_runtime_put_sync(dwc->dev);
818ec3aba883f5 Felipe Balbi   2016-04-14  734  	return 0;
818ec3aba883f5 Felipe Balbi   2016-04-14  735  }

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

Re: [PATCH v8] usb: dwc3: debugfs: Prevent any register access when devices is runtime suspended

[Johan Hovold]

On Wed, May 10, 2023 at 10:32:54AM +0300, Dan Carpenter wrote:
> Hi Udipto,
> 
> kernel test robot noticed the following build warnings:
> 
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Udipto-Goswami/usb-dwc3-debugfs-Prevent-any-register-access-when-devices-is-runtime-suspended/20230504-125225
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
> patch link:    https://lore.kernel.org/r/20230504045052.22347-1-quic_ugoswami%40quicinc.com
> patch subject: [PATCH v8] usb: dwc3: debugfs: Prevent any register access when devices is runtime suspended
> config: x86_64-randconfig-m001 (https://download.01.org/0day-ci/archive/20230510/202305101451.V2D0cM4S-lkp@intel.com/config)
> compiler: gcc-11 (Debian 11.3.0-12) 11.3.0
> 
> If you fix the issue, kindly add following tag where applicable
> | Reported-by: kernel test robot <lkp@intel.com>
> | Reported-by: Dan Carpenter <error27@gmail.com>
> | Link: https://lore.kernel.org/r/202305101451.V2D0cM4S-lkp@intel.com/
> 
> New smatch warnings:
> drivers/usb/dwc3/debugfs.c:647 dwc3_link_state_write() warn: missing error code? 'ret'
> drivers/usb/dwc3/debugfs.c:720 dwc3_rx_fifo_size_show() warn: curly braces intended?
> drivers/usb/dwc3/debugfs.c:722 dwc3_rx_fifo_size_show() warn: inconsistent indenting
> drivers/usb/dwc3/debugfs.c:722 dwc3_rx_fifo_size_show() warn: ignoring unreachable code.
> 
> Old smatch warnings:
> drivers/usb/dwc3/debugfs.c:657 dwc3_link_state_write() warn: missing error code? 'ret'
> 
> vim +/ret +647 drivers/usb/dwc3/debugfs.c
> 
> 1c53edaeee3338 Udipto Goswami 2023-05-04  638  	ret = pm_runtime_resume_and_get(dwc->dev);
> 1c53edaeee3338 Udipto Goswami 2023-05-04  639  	if (ret < 0)
> 1c53edaeee3338 Udipto Goswami 2023-05-04  640  		return ret;
> 1c53edaeee3338 Udipto Goswami 2023-05-04  641  
> 138801aaa566ec Felipe Balbi   2012-01-02  642  	spin_lock_irqsave(&dwc->lock, flags);
> d102444cac1564 Thinh Nguyen   2018-11-07  643  	reg = dwc3_readl(dwc->regs, DWC3_GSTS);
> d102444cac1564 Thinh Nguyen   2018-11-07  644  	if (DWC3_GSTS_CURMOD(reg) != DWC3_GSTS_CURMOD_DEVICE) {
> d102444cac1564 Thinh Nguyen   2018-11-07  645  		spin_unlock_irqrestore(&dwc->lock, flags);
> 1c53edaeee3338 Udipto Goswami 2023-05-04  646  		pm_runtime_put_sync(dwc->dev);
> 1c53edaeee3338 Udipto Goswami 2023-05-04 @647  		return ret;
> 
> ret is not necessarily an error code.
> 
> d102444cac1564 Thinh Nguyen   2018-11-07  648  	}
> d102444cac1564 Thinh Nguyen   2018-11-07  649  
> 0d36dede457873 Thinh Nguyen   2018-11-07  650  	reg = dwc3_readl(dwc->regs, DWC3_DSTS);
> 0d36dede457873 Thinh Nguyen   2018-11-07  651  	speed = reg & DWC3_DSTS_CONNECTSPD;
> 0d36dede457873 Thinh Nguyen   2018-11-07  652  
> 0d36dede457873 Thinh Nguyen   2018-11-07  653  	if (speed < DWC3_DSTS_SUPERSPEED &&
> 0d36dede457873 Thinh Nguyen   2018-11-07  654  	    state != DWC3_LINK_STATE_RECOV) {
> 0d36dede457873 Thinh Nguyen   2018-11-07  655  		spin_unlock_irqrestore(&dwc->lock, flags);
> 1c53edaeee3338 Udipto Goswami 2023-05-04  656  		pm_runtime_put_sync(dwc->dev);
> 1c53edaeee3338 Udipto Goswami 2023-05-04  657  		return ret;
> 0d36dede457873 Thinh Nguyen   2018-11-07  658  	}
> 
> [ snip ]
> 
> 2c85a1817e4ba0 Thinh Nguyen   2018-11-07  708  static int dwc3_rx_fifo_size_show(struct seq_file *s, void *unused)
> 818ec3aba883f5 Felipe Balbi   2016-04-14  709  {
> 818ec3aba883f5 Felipe Balbi   2016-04-14  710  	struct dwc3_ep		*dep = s->private;
> 818ec3aba883f5 Felipe Balbi   2016-04-14  711  	struct dwc3		*dwc = dep->dwc;
> 818ec3aba883f5 Felipe Balbi   2016-04-14  712  	unsigned long		flags;
> d00be779cc5016 Thinh Nguyen   2021-03-27  713  	u32			mdwidth;
> 818ec3aba883f5 Felipe Balbi   2016-04-14  714  	u32			val;
> 1c53edaeee3338 Udipto Goswami 2023-05-04  715  	int			ret;
> 1c53edaeee3338 Udipto Goswami 2023-05-04  716  
> 1c53edaeee3338 Udipto Goswami 2023-05-04  717  	ret = pm_runtime_resume_and_get(dwc->dev);
> 1c53edaeee3338 Udipto Goswami 2023-05-04  718  	if (ret < 0)
> 1c53edaeee3338 Udipto Goswami 2023-05-04  719  		pm_runtime_put_sync(dwc->dev);
> 1c53edaeee3338 Udipto Goswami 2023-05-04 @720  		return ret;
> 
> Needs curly braces.

I believe this was all fixed in v9/v10.

Johan