[PATCH AUTOSEL 4.14 01/17] ARM: dts: omap4-droid4: Fix spi configuration and increase rate

[PATCH AUTOSEL 4.14 01/17] ARM: dts: omap4-droid4: Fix spi configuration and increase rate

[Sasha Levin]

From: Tony Lindgren <tony@atomide.com>

[ Upstream commit 0df12a01f4857495816b05f048c4c31439446e35 ]

We can currently sometimes get "RXS timed out" errors and "EOT timed out"
errors with spi transfers.

These errors can be made easy to reproduce by reading the cpcap iio
values in a loop while keeping the CPUs busy by also reading /dev/urandom.

The "RXS timed out" errors we can fix by adding spi-cpol and spi-cpha
in addition to the spi-cs-high property we already have.

The "EOT timed out" errors we can fix by increasing the spi clock rate
to 9.6 MHz. Looks similar MC13783 PMIC says it works at spi clock rates
up to 20 MHz, so let's assume we can pick any rate up to 20 MHz also
for cpcap.

Cc: maemo-leste@lists.dyne.org
Cc: Merlijn Wajer <merlijn@wizzup.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm/boot/dts/motorola-cpcap-mapphone.dtsi | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/motorola-cpcap-mapphone.dtsi b/arch/arm/boot/dts/motorola-cpcap-mapphone.dtsi
index bcced922b2807..b4779b0ece96d 100644
--- a/arch/arm/boot/dts/motorola-cpcap-mapphone.dtsi
+++ b/arch/arm/boot/dts/motorola-cpcap-mapphone.dtsi
@@ -16,8 +16,10 @@ cpcap: pmic@0 {
 		#interrupt-cells = <2>;
 		#address-cells = <1>;
 		#size-cells = <0>;
-		spi-max-frequency = <3000000>;
+		spi-max-frequency = <9600000>;
 		spi-cs-high;
+		spi-cpol;
+		spi-cpha;
 
 		cpcap_adc: adc {
 			compatible = "motorola,mapphone-cpcap-adc";
-- 
2.25.1

[PATCH AUTOSEL 4.14 02/17] gpu: host1x: Detach driver on unregister

[Sasha Levin]

From: Thierry Reding <treding@nvidia.com>

[ Upstream commit d9a0a05bf8c76e6dc79230669a8b5d685b168c30 ]

Currently when a host1x device driver is unregistered, it is not
detached from the host1x controller, which means that the device
will stay around and when the driver is registered again, it may
bind to the old, stale device rather than the new one that was
created from scratch upon driver registration. This in turn can
cause various weird crashes within the driver core because it is
confronted with a device that was already deleted.

Fix this by detaching the driver from the host1x controller when
it is unregistered. This ensures that the deleted device also is
no longer present in the device list that drivers will bind to.

Reported-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Tested-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/host1x/bus.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/host1x/bus.c b/drivers/gpu/host1x/bus.c
index f9cde03030fd9..c2a9dcf6f4907 100644
--- a/drivers/gpu/host1x/bus.c
+++ b/drivers/gpu/host1x/bus.c
@@ -615,8 +615,17 @@ EXPORT_SYMBOL(host1x_driver_register_full);
  */
 void host1x_driver_unregister(struct host1x_driver *driver)
 {
+	struct host1x *host1x;
+
 	driver_unregister(&driver->driver);
 
+	mutex_lock(&devices_lock);
+
+	list_for_each_entry(host1x, &devices, list)
+		host1x_detach_driver(host1x, driver);
+
+	mutex_unlock(&devices_lock);
+
 	mutex_lock(&drivers_lock);
 	list_del_init(&driver->list);
 	mutex_unlock(&drivers_lock);
-- 
2.25.1

[PATCH AUTOSEL 4.14 03/17] net: usb: ax88179_178a: fix packet alignment padding

[Sasha Levin]

From: Jeremy Kerr <jk@ozlabs.org>

[ Upstream commit e869e7a17798d85829fa7d4f9bbe1eebd4b2d3f6 ]

Using a AX88179 device (0b95:1790), I see two bytes of appended data on
every RX packet. For example, this 48-byte ping, using 0xff as a
payload byte:

  04:20:22.528472 IP 192.168.1.1 > 192.168.1.2: ICMP echo request, id 2447, seq 1, length 64
	0x0000:  000a cd35 ea50 000a cd35 ea4f 0800 4500
	0x0010:  0054 c116 4000 4001 f63e c0a8 0101 c0a8
	0x0020:  0102 0800 b633 098f 0001 87ea cd5e 0000
	0x0030:  0000 dcf2 0600 0000 0000 ffff ffff ffff
	0x0040:  ffff ffff ffff ffff ffff ffff ffff ffff
	0x0050:  ffff ffff ffff ffff ffff ffff ffff ffff
	0x0060:  ffff 961f

Those last two bytes - 96 1f - aren't part of the original packet.

In the ax88179 RX path, the usbnet rx_fixup function trims a 2-byte
'alignment pseudo header' from the start of the packet, and sets the
length from a per-packet field populated by hardware. It looks like that
length field *includes* the 2-byte header; the current driver assumes
that it's excluded.

This change trims the 2-byte alignment header after we've set the packet
length, so the resulting packet length is correct. While we're moving
the comment around, this also fixes the spelling of 'pseudo'.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/usb/ax88179_178a.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/net/usb/ax88179_178a.c b/drivers/net/usb/ax88179_178a.c
index 0f69b77e8502b..875639b0e9d56 100644
--- a/drivers/net/usb/ax88179_178a.c
+++ b/drivers/net/usb/ax88179_178a.c
@@ -1400,10 +1400,10 @@ static int ax88179_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 		}
 
 		if (pkt_cnt == 0) {
-			/* Skip IP alignment psudo header */
-			skb_pull(skb, 2);
 			skb->len = pkt_len;
-			skb_set_tail_pointer(skb, pkt_len);
+			/* Skip IP alignment pseudo header */
+			skb_pull(skb, 2);
+			skb_set_tail_pointer(skb, skb->len);
 			skb->truesize = pkt_len + sizeof(struct sk_buff);
 			ax88179_rx_checksum(skb, pkt_hdr);
 			return 1;
@@ -1412,8 +1412,9 @@ static int ax88179_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 		ax_skb = skb_clone(skb, GFP_ATOMIC);
 		if (ax_skb) {
 			ax_skb->len = pkt_len;
-			ax_skb->data = skb->data + 2;
-			skb_set_tail_pointer(ax_skb, pkt_len);
+			/* Skip IP alignment pseudo header */
+			skb_pull(ax_skb, 2);
+			skb_set_tail_pointer(ax_skb, ax_skb->len);
 			ax_skb->truesize = pkt_len + sizeof(struct sk_buff);
 			ax88179_rx_checksum(ax_skb, pkt_hdr);
 			usbnet_skb_return(dev, ax_skb);
-- 
2.25.1

[PATCH AUTOSEL 4.14 04/17] usb: usbtest: fix missing kfree(dev->buf) in usbtest_disconnect

[Sasha Levin]

From: Zqiang <qiang.zhang@windriver.com>

[ Upstream commit 28ebeb8db77035e058a510ce9bd17c2b9a009dba ]

BUG: memory leak
unreferenced object 0xffff888055046e00 (size 256):
  comm "kworker/2:9", pid 2570, jiffies 4294942129 (age 1095.500s)
  hex dump (first 32 bytes):
    00 70 04 55 80 88 ff ff 18 bb 5a 81 ff ff ff ff  .p.U......Z.....
    f5 96 78 81 ff ff ff ff 37 de 8e 81 ff ff ff ff  ..x.....7.......
  backtrace:
    [<00000000d121dccf>] kmemleak_alloc_recursive
include/linux/kmemleak.h:43 [inline]
    [<00000000d121dccf>] slab_post_alloc_hook mm/slab.h:586 [inline]
    [<00000000d121dccf>] slab_alloc_node mm/slub.c:2786 [inline]
    [<00000000d121dccf>] slab_alloc mm/slub.c:2794 [inline]
    [<00000000d121dccf>] kmem_cache_alloc_trace+0x15e/0x2d0 mm/slub.c:2811
    [<000000005c3c3381>] kmalloc include/linux/slab.h:555 [inline]
    [<000000005c3c3381>] usbtest_probe+0x286/0x19d0
drivers/usb/misc/usbtest.c:2790
    [<000000001cec6910>] usb_probe_interface+0x2bd/0x870
drivers/usb/core/driver.c:361
    [<000000007806c118>] really_probe+0x48d/0x8f0 drivers/base/dd.c:551
    [<00000000a3308c3e>] driver_probe_device+0xfc/0x2a0 drivers/base/dd.c:724
    [<000000003ef66004>] __device_attach_driver+0x1b6/0x240
drivers/base/dd.c:831
    [<00000000eee53e97>] bus_for_each_drv+0x14e/0x1e0 drivers/base/bus.c:431
    [<00000000bb0648d0>] __device_attach+0x1f9/0x350 drivers/base/dd.c:897
    [<00000000838b324a>] device_initial_probe+0x1a/0x20 drivers/base/dd.c:944
    [<0000000030d501c1>] bus_probe_device+0x1e1/0x280 drivers/base/bus.c:491
    [<000000005bd7adef>] device_add+0x131d/0x1c40 drivers/base/core.c:2504
    [<00000000a0937814>] usb_set_configuration+0xe84/0x1ab0
drivers/usb/core/message.c:2030
    [<00000000e3934741>] generic_probe+0x6a/0xe0 drivers/usb/core/generic.c:210
    [<0000000098ade0f1>] usb_probe_device+0x90/0xd0
drivers/usb/core/driver.c:266
    [<000000007806c118>] really_probe+0x48d/0x8f0 drivers/base/dd.c:551
    [<00000000a3308c3e>] driver_probe_device+0xfc/0x2a0 drivers/base/dd.c:724

Acked-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Kyungtae Kim <kt0755@gmail.com>
Signed-off-by: Zqiang <qiang.zhang@windriver.com>
Link: https://lore.kernel.org/r/20200612035210.20494-1-qiang.zhang@windriver.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/misc/usbtest.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/misc/usbtest.c b/drivers/usb/misc/usbtest.c
index b3fc602b2e247..49476c0304b27 100644
--- a/drivers/usb/misc/usbtest.c
+++ b/drivers/usb/misc/usbtest.c
@@ -2769,6 +2769,7 @@ static void usbtest_disconnect(struct usb_interface *intf)
 
 	usb_set_intfdata(intf, NULL);
 	dev_dbg(&intf->dev, "disconnect\n");
+	kfree(dev->buf);
 	kfree(dev);
 }
 
-- 
2.25.1

[PATCH AUTOSEL 4.14 05/17] spi: spidev: fix a race between spidev_release and spidev_remove

[Sasha Levin]

From: Zhenzhong Duan <zhenzhong.duan@gmail.com>

[ Upstream commit abd42781c3d2155868821f1b947ae45bbc33330d ]

Imagine below scene, spidev is referenced after it's freed.

spidev_release()                spidev_remove()
...
                                spin_lock_irq(&spidev->spi_lock);
                                    spidev->spi = NULL;
                                spin_unlock_irq(&spidev->spi_lock);
mutex_lock(&device_list_lock);
dofree = (spidev->spi == NULL);
if (dofree)
    kfree(spidev);
mutex_unlock(&device_list_lock);
                                mutex_lock(&device_list_lock);
                                list_del(&spidev->device_entry);
                                device_destroy(spidev_class, spidev->devt);
                                clear_bit(MINOR(spidev->devt), minors);
                                if (spidev->users == 0)
                                    kfree(spidev);
                                mutex_unlock(&device_list_lock);

Fix it by resetting spidev->spi in device_list_lock's protection.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@gmail.com>
Link: https://lore.kernel.org/r/20200618032125.4650-1-zhenzhong.duan@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spidev.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 028725573e632..5edf4029a3486 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -782,13 +782,13 @@ static int spidev_remove(struct spi_device *spi)
 {
 	struct spidev_data	*spidev = spi_get_drvdata(spi);
 
+	/* prevent new opens */
+	mutex_lock(&device_list_lock);
 	/* make sure ops on existing fds can abort cleanly */
 	spin_lock_irq(&spidev->spi_lock);
 	spidev->spi = NULL;
 	spin_unlock_irq(&spidev->spi_lock);
 
-	/* prevent new opens */
-	mutex_lock(&device_list_lock);
 	list_del(&spidev->device_entry);
 	device_destroy(spidev_class, spidev->devt);
 	clear_bit(MINOR(spidev->devt), minors);
-- 
2.25.1

[PATCH AUTOSEL 4.14 06/17] spi: spidev: fix a potential use-after-free in spidev_release()

[Sasha Levin]

From: Zhenzhong Duan <zhenzhong.duan@gmail.com>

[ Upstream commit 06096cc6c5a84ced929634b0d79376b94c65a4bd ]

If an spi device is unbounded from the driver before the release
process, there will be an NULL pointer reference when it's
referenced in spi_slave_abort().

Fix it by checking it's already freed before reference.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@gmail.com>
Link: https://lore.kernel.org/r/20200618032125.4650-2-zhenzhong.duan@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spidev.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 5edf4029a3486..167047760d79a 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -607,15 +607,20 @@ static int spidev_open(struct inode *inode, struct file *filp)
 static int spidev_release(struct inode *inode, struct file *filp)
 {
 	struct spidev_data	*spidev;
+	int			dofree;
 
 	mutex_lock(&device_list_lock);
 	spidev = filp->private_data;
 	filp->private_data = NULL;
 
+	spin_lock_irq(&spidev->spi_lock);
+	/* ... after we unbound from the underlying device? */
+	dofree = (spidev->spi == NULL);
+	spin_unlock_irq(&spidev->spi_lock);
+
 	/* last close? */
 	spidev->users--;
 	if (!spidev->users) {
-		int		dofree;
 
 		kfree(spidev->tx_buffer);
 		spidev->tx_buffer = NULL;
@@ -623,19 +628,14 @@ static int spidev_release(struct inode *inode, struct file *filp)
 		kfree(spidev->rx_buffer);
 		spidev->rx_buffer = NULL;
 
-		spin_lock_irq(&spidev->spi_lock);
-		if (spidev->spi)
-			spidev->speed_hz = spidev->spi->max_speed_hz;
-
-		/* ... after we unbound from the underlying device? */
-		dofree = (spidev->spi == NULL);
-		spin_unlock_irq(&spidev->spi_lock);
-
 		if (dofree)
 			kfree(spidev);
+		else
+			spidev->speed_hz = spidev->spi->max_speed_hz;
 	}
 #ifdef CONFIG_SPI_SLAVE
-	spi_slave_abort(spidev->spi);
+	if (!dofree)
+		spi_slave_abort(spidev->spi);
 #endif
 	mutex_unlock(&device_list_lock);
 
-- 
2.25.1

[PATCH AUTOSEL 4.14 07/17] tg3: driver sleeps indefinitely when EEH errors exceed eeh_max_freezes

[Sasha Levin]

From: David Christensen <drc@linux.vnet.ibm.com>

[ Upstream commit 3a2656a211caf35e56afc9425e6e518fa52f7fbc ]

The driver function tg3_io_error_detected() calls napi_disable twice,
without an intervening napi_enable, when the number of EEH errors exceeds
eeh_max_freezes, resulting in an indefinite sleep while holding rtnl_lock.

Add check for pcierr_recovery which skips code already executed for the
"Frozen" state.

Signed-off-by: David Christensen <drc@linux.vnet.ibm.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/broadcom/tg3.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index bc0221eafe5c4..e40d31b405253 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -18179,8 +18179,8 @@ static pci_ers_result_t tg3_io_error_detected(struct pci_dev *pdev,
 
 	rtnl_lock();
 
-	/* We probably don't have netdev yet */
-	if (!netdev || !netif_running(netdev))
+	/* Could be second call or maybe we don't have netdev yet */
+	if (!netdev || tp->pcierr_recovery || !netif_running(netdev))
 		goto done;
 
 	/* We needn't recover from permanent error */
-- 
2.25.1

[PATCH AUTOSEL 4.14 08/17] ixgbe: protect ring accesses with READ- and WRITE_ONCE

[Sasha Levin]

From: Ciara Loftus <ciara.loftus@intel.com>

[ Upstream commit f140ad9fe2ae16f385f8fe4dc9cf67bb4c51d794 ]

READ_ONCE should be used when reading rings prior to accessing the
statistics pointer. Introduce this as well as the corresponding WRITE_ONCE
usage when allocating and freeing the rings, to ensure protected access.

Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c  | 12 ++++++------
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 14 +++++++++++---
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
index f1bfae0c41d0c..3cf8b3ea43b08 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
@@ -917,7 +917,7 @@ static int ixgbe_alloc_q_vector(struct ixgbe_adapter *adapter,
 			ring->queue_index = txr_idx;
 
 		/* assign ring to adapter */
-		adapter->tx_ring[txr_idx] = ring;
+		WRITE_ONCE(adapter->tx_ring[txr_idx], ring);
 
 		/* update count and index */
 		txr_count--;
@@ -944,7 +944,7 @@ static int ixgbe_alloc_q_vector(struct ixgbe_adapter *adapter,
 		set_ring_xdp(ring);
 
 		/* assign ring to adapter */
-		adapter->xdp_ring[xdp_idx] = ring;
+		WRITE_ONCE(adapter->xdp_ring[xdp_idx], ring);
 
 		/* update count and index */
 		xdp_count--;
@@ -991,7 +991,7 @@ static int ixgbe_alloc_q_vector(struct ixgbe_adapter *adapter,
 			ring->queue_index = rxr_idx;
 
 		/* assign ring to adapter */
-		adapter->rx_ring[rxr_idx] = ring;
+		WRITE_ONCE(adapter->rx_ring[rxr_idx], ring);
 
 		/* update count and index */
 		rxr_count--;
@@ -1020,13 +1020,13 @@ static void ixgbe_free_q_vector(struct ixgbe_adapter *adapter, int v_idx)
 
 	ixgbe_for_each_ring(ring, q_vector->tx) {
 		if (ring_is_xdp(ring))
-			adapter->xdp_ring[ring->queue_index] = NULL;
+			WRITE_ONCE(adapter->xdp_ring[ring->queue_index], NULL);
 		else
-			adapter->tx_ring[ring->queue_index] = NULL;
+			WRITE_ONCE(adapter->tx_ring[ring->queue_index], NULL);
 	}
 
 	ixgbe_for_each_ring(ring, q_vector->rx)
-		adapter->rx_ring[ring->queue_index] = NULL;
+		WRITE_ONCE(adapter->rx_ring[ring->queue_index], NULL);
 
 	adapter->q_vector[v_idx] = NULL;
 	napi_hash_del(&q_vector->napi);
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 64ee45b6680a0..9c3fa0b555519 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -6842,7 +6842,10 @@ void ixgbe_update_stats(struct ixgbe_adapter *adapter)
 	}
 
 	for (i = 0; i < adapter->num_rx_queues; i++) {
-		struct ixgbe_ring *rx_ring = adapter->rx_ring[i];
+		struct ixgbe_ring *rx_ring = READ_ONCE(adapter->rx_ring[i]);
+
+		if (!rx_ring)
+			continue;
 		non_eop_descs += rx_ring->rx_stats.non_eop_descs;
 		alloc_rx_page_failed += rx_ring->rx_stats.alloc_rx_page_failed;
 		alloc_rx_buff_failed += rx_ring->rx_stats.alloc_rx_buff_failed;
@@ -6861,15 +6864,20 @@ void ixgbe_update_stats(struct ixgbe_adapter *adapter)
 	packets = 0;
 	/* gather some stats to the adapter struct that are per queue */
 	for (i = 0; i < adapter->num_tx_queues; i++) {
-		struct ixgbe_ring *tx_ring = adapter->tx_ring[i];
+		struct ixgbe_ring *tx_ring = READ_ONCE(adapter->tx_ring[i]);
+
+		if (!tx_ring)
+			continue;
 		restart_queue += tx_ring->tx_stats.restart_queue;
 		tx_busy += tx_ring->tx_stats.tx_busy;
 		bytes += tx_ring->stats.bytes;
 		packets += tx_ring->stats.packets;
 	}
 	for (i = 0; i < adapter->num_xdp_queues; i++) {
-		struct ixgbe_ring *xdp_ring = adapter->xdp_ring[i];
+		struct ixgbe_ring *xdp_ring = READ_ONCE(adapter->xdp_ring[i]);
 
+		if (!xdp_ring)
+			continue;
 		restart_queue += xdp_ring->tx_stats.restart_queue;
 		tx_busy += xdp_ring->tx_stats.tx_busy;
 		bytes += xdp_ring->stats.bytes;
-- 
2.25.1

[PATCH AUTOSEL 4.14 09/17] usbnet: smsc95xx: Fix use-after-free after removal

[Sasha Levin]

From: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>

[ Upstream commit b835a71ef64a61383c414d6bf2896d2c0161deca ]

Syzbot reports an use-after-free in workqueue context:

BUG: KASAN: use-after-free in mutex_unlock+0x19/0x40 kernel/locking/mutex.c:737
 mutex_unlock+0x19/0x40 kernel/locking/mutex.c:737
 __smsc95xx_mdio_read drivers/net/usb/smsc95xx.c:217 [inline]
 smsc95xx_mdio_read+0x583/0x870 drivers/net/usb/smsc95xx.c:278
 check_carrier+0xd1/0x2e0 drivers/net/usb/smsc95xx.c:644
 process_one_work+0x777/0xf90 kernel/workqueue.c:2274
 worker_thread+0xa8f/0x1430 kernel/workqueue.c:2420
 kthread+0x2df/0x300 kernel/kthread.c:255

It looks like that smsc95xx_unbind() is freeing the structures that are
still in use by the concurrently running workqueue callback. Thus switch
to using cancel_delayed_work_sync() to ensure the work callback really
is no longer active.

Reported-by: syzbot+29dc7d4ae19b703ff947@syzkaller.appspotmail.com
Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/usb/smsc95xx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
index fc48da1c702d7..bcb99bee450a5 100644
--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c
@@ -1338,7 +1338,7 @@ static void smsc95xx_unbind(struct usbnet *dev, struct usb_interface *intf)
 	struct smsc95xx_priv *pdata = (struct smsc95xx_priv *)(dev->data[0]);
 
 	if (pdata) {
-		cancel_delayed_work(&pdata->carrier_check);
+		cancel_delayed_work_sync(&pdata->carrier_check);
 		netif_dbg(dev, ifdown, dev->net, "free pdata\n");
 		kfree(pdata);
 		pdata = NULL;
-- 
2.25.1

[PATCH AUTOSEL 4.14 10/17] s390/kasan: fix early pgm check handler execution

[Sasha Levin]

From: Vasily Gorbik <gor@linux.ibm.com>

[ Upstream commit 998f5bbe3dbdab81c1cfb1aef7c3892f5d24f6c7 ]

Currently if early_pgm_check_handler is called it ends up in pgm check
loop. The problem is that early_pgm_check_handler is instrumented by
KASAN but executed without DAT flag enabled which leads to addressing
exception when KASAN checks try to access shadow memory.

Fix that by executing early handlers with DAT flag on under KASAN as
expected.

Reported-and-tested-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/s390/kernel/early.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 4ba5ad44a21a2..73045142febf0 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -317,6 +317,8 @@ static noinline __init void setup_lowcore_early(void)
 	psw_t psw;
 
 	psw.mask = PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA;
+	if (IS_ENABLED(CONFIG_KASAN))
+		psw.mask |= PSW_MASK_DAT;
 	psw.addr = (unsigned long) s390_base_ext_handler;
 	S390_lowcore.external_new_psw = psw;
 	psw.addr = (unsigned long) s390_base_pgm_handler;
-- 
2.25.1

[PATCH AUTOSEL 4.14 11/17] cifs: Fix double add page to memcg when cifs_readpages

[Sasha Levin]

From: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>

[ Upstream commit 95a3d8f3af9b0d63b43f221b630beaab9739d13a ]

When xfstests generic/451, there is an BUG at mm/memcontrol.c:
  page:ffffea000560f2c0 refcount:2 mapcount:0 mapping:000000008544e0ea
       index:0xf
  mapping->aops:cifs_addr_ops dentry name:"tst-aio-dio-cycle-write.451"
  flags: 0x2fffff80000001(locked)
  raw: 002fffff80000001 ffffc90002023c50 ffffea0005280088 ffff88815cda0210
  raw: 000000000000000f 0000000000000000 00000002ffffffff ffff88817287d000
  page dumped because: VM_BUG_ON_PAGE(page->mem_cgroup)
  page->mem_cgroup:ffff88817287d000
  ------------[ cut here ]------------
  kernel BUG at mm/memcontrol.c:2659!
  invalid opcode: 0000 [#1] SMP
  CPU: 2 PID: 2038 Comm: xfs_io Not tainted 5.8.0-rc1 #44
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_
    073836-buildvm-ppc64le-16.ppc.4
  RIP: 0010:commit_charge+0x35/0x50
  Code: 0d 48 83 05 54 b2 02 05 01 48 89 77 38 c3 48 c7
        c6 78 4a ea ba 48 83 05 38 b2 02 05 01 e8 63 0d9
  RSP: 0018:ffffc90002023a50 EFLAGS: 00010202
  RAX: 0000000000000000 RBX: ffff88817287d000 RCX: 0000000000000000
  RDX: 0000000000000000 RSI: ffff88817ac97ea0 RDI: ffff88817ac97ea0
  RBP: ffffea000560f2c0 R08: 0000000000000203 R09: 0000000000000005
  R10: 0000000000000030 R11: ffffc900020237a8 R12: 0000000000000000
  R13: 0000000000000001 R14: 0000000000000001 R15: ffff88815a1272c0
  FS:  00007f5071ab0800(0000) GS:ffff88817ac80000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 000055efcd5ca000 CR3: 000000015d312000 CR4: 00000000000006e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   mem_cgroup_charge+0x166/0x4f0
   __add_to_page_cache_locked+0x4a9/0x710
   add_to_page_cache_locked+0x15/0x20
   cifs_readpages+0x217/0x1270
   read_pages+0x29a/0x670
   page_cache_readahead_unbounded+0x24f/0x390
   __do_page_cache_readahead+0x3f/0x60
   ondemand_readahead+0x1f1/0x470
   page_cache_async_readahead+0x14c/0x170
   generic_file_buffered_read+0x5df/0x1100
   generic_file_read_iter+0x10c/0x1d0
   cifs_strict_readv+0x139/0x170
   new_sync_read+0x164/0x250
   __vfs_read+0x39/0x60
   vfs_read+0xb5/0x1e0
   ksys_pread64+0x85/0xf0
   __x64_sys_pread64+0x22/0x30
   do_syscall_64+0x69/0x150
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  RIP: 0033:0x7f5071fcb1af
  Code: Bad RIP value.
  RSP: 002b:00007ffde2cdb8e0 EFLAGS: 00000293 ORIG_RAX: 0000000000000011
  RAX: ffffffffffffffda RBX: 00007ffde2cdb990 RCX: 00007f5071fcb1af
  RDX: 0000000000001000 RSI: 000055efcd5ca000 RDI: 0000000000000003
  RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000001000 R11: 0000000000000293 R12: 0000000000000001
  R13: 000000000009f000 R14: 0000000000000000 R15: 0000000000001000
  Modules linked in:
  ---[ end trace 725fa14a3e1af65c ]---

Since commit 3fea5a499d57 ("mm: memcontrol: convert page cache to a new
mem_cgroup_charge() API") not cancel the page charge, the pages maybe
double add to pagecache:
thread1                       | thread2
cifs_readpages
readpages_get_pages
 add_to_page_cache_locked(head,index=n)=0
                              | readpages_get_pages
                              | add_to_page_cache_locked(head,index=n+1)=0
 add_to_page_cache_locked(head, index=n+1)=-EEXIST
 then, will next loop with list head page's
 index=n+1 and the page->mapping not NULL
readpages_get_pages
add_to_page_cache_locked(head, index=n+1)
 commit_charge
  VM_BUG_ON_PAGE

So, we should not do the next loop when any page add to page cache
failed.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/cifs/file.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 72e7cbfb325a6..b71a2ae60ad07 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3753,7 +3753,8 @@ readpages_get_pages(struct address_space *mapping, struct list_head *page_list,
 			break;
 
 		__SetPageLocked(page);
-		if (add_to_page_cache_locked(page, mapping, page->index, gfp)) {
+		rc = add_to_page_cache_locked(page, mapping, page->index, gfp);
+		if (rc) {
 			__ClearPageLocked(page);
 			break;
 		}
@@ -3769,6 +3770,7 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
 	struct list_head *page_list, unsigned num_pages)
 {
 	int rc;
+	int err = 0;
 	struct list_head tmplist;
 	struct cifsFileInfo *open_file = file->private_data;
 	struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
@@ -3809,7 +3811,7 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
 	 * the order of declining indexes. When we put the pages in
 	 * the rdata->pages, then we want them in increasing order.
 	 */
-	while (!list_empty(page_list)) {
+	while (!list_empty(page_list) && !err) {
 		unsigned int i, nr_pages, bytes, rsize;
 		loff_t offset;
 		struct page *page, *tpage;
@@ -3832,9 +3834,10 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
 			return 0;
 		}
 
-		rc = readpages_get_pages(mapping, page_list, rsize, &tmplist,
+		nr_pages = 0;
+		err = readpages_get_pages(mapping, page_list, rsize, &tmplist,
 					 &nr_pages, &offset, &bytes);
-		if (rc) {
+		if (!nr_pages) {
 			add_credits_and_wake_if(server, credits, 0);
 			break;
 		}
-- 
2.25.1

[PATCH AUTOSEL 4.14 12/17] cifs: update ctime and mtime during truncate

[Sasha Levin]

From: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>

[ Upstream commit 5618303d8516f8ac5ecfe53ee8e8bc9a40eaf066 ]

As the man description of the truncate, if the size changed,
then the st_ctime and st_mtime fields should be updated. But
in cifs, we doesn't do it.

It lead the xfstests generic/313 failed.

So, add the ATTR_MTIME|ATTR_CTIME flags on attrs when change
the file size

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/cifs/inode.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index bdce714e94489..b76e733952997 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -2210,6 +2210,15 @@ cifs_set_file_size(struct inode *inode, struct iattr *attrs,
 	if (rc == 0) {
 		cifsInode->server_eof = attrs->ia_size;
 		cifs_setsize(inode, attrs->ia_size);
+
+		/*
+		 * The man page of truncate says if the size changed,
+		 * then the st_ctime and st_mtime fields for the file
+		 * are updated.
+		 */
+		attrs->ia_ctime = attrs->ia_mtime = current_time(inode);
+		attrs->ia_valid |= ATTR_CTIME | ATTR_MTIME;
+
 		cifs_truncate_page(inode->i_mapping, inode->i_size);
 	}
 
-- 
2.25.1

[PATCH AUTOSEL 4.14 13/17] ARM: imx6: add missing put_device() call in imx6q_suspend_init()

[Sasha Levin]

From: yu kuai <yukuai3@huawei.com>

[ Upstream commit 4845446036fc9c13f43b54a65c9b757c14f5141b ]

if of_find_device_by_node() succeed, imx6q_suspend_init() doesn't have a
corresponding put_device(). Thus add a jump target to fix the exception
handling for this function implementation.

Signed-off-by: yu kuai <yukuai3@huawei.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm/mach-imx/pm-imx6.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/arm/mach-imx/pm-imx6.c b/arch/arm/mach-imx/pm-imx6.c
index 6078bcc9f594a..c7dcb0b207301 100644
--- a/arch/arm/mach-imx/pm-imx6.c
+++ b/arch/arm/mach-imx/pm-imx6.c
@@ -483,14 +483,14 @@ static int __init imx6q_suspend_init(const struct imx6_pm_socdata *socdata)
 	if (!ocram_pool) {
 		pr_warn("%s: ocram pool unavailable!\n", __func__);
 		ret = -ENODEV;
-		goto put_node;
+		goto put_device;
 	}
 
 	ocram_base = gen_pool_alloc(ocram_pool, MX6Q_SUSPEND_OCRAM_SIZE);
 	if (!ocram_base) {
 		pr_warn("%s: unable to alloc ocram!\n", __func__);
 		ret = -ENOMEM;
-		goto put_node;
+		goto put_device;
 	}
 
 	ocram_pbase = gen_pool_virt_to_phys(ocram_pool, ocram_base);
@@ -513,7 +513,7 @@ static int __init imx6q_suspend_init(const struct imx6_pm_socdata *socdata)
 	ret = imx6_pm_get_base(&pm_info->mmdc_base, socdata->mmdc_compat);
 	if (ret) {
 		pr_warn("%s: failed to get mmdc base %d!\n", __func__, ret);
-		goto put_node;
+		goto put_device;
 	}
 
 	ret = imx6_pm_get_base(&pm_info->src_base, socdata->src_compat);
@@ -560,7 +560,7 @@ static int __init imx6q_suspend_init(const struct imx6_pm_socdata *socdata)
 		&imx6_suspend,
 		MX6Q_SUSPEND_OCRAM_SIZE - sizeof(*pm_info));
 
-	goto put_node;
+	goto put_device;
 
 pl310_cache_map_failed:
 	iounmap(pm_info->gpc_base.vbase);
@@ -570,6 +570,8 @@ static int __init imx6q_suspend_init(const struct imx6_pm_socdata *socdata)
 	iounmap(pm_info->src_base.vbase);
 src_map_failed:
 	iounmap(pm_info->mmdc_base.vbase);
+put_device:
+	put_device(&pdev->dev);
 put_node:
 	of_node_put(node);
 
-- 
2.25.1

[PATCH AUTOSEL 4.14 14/17] scsi: mptscsih: Fix read sense data size

[Sasha Levin]

From: Tomas Henzl <thenzl@redhat.com>

[ Upstream commit afe89f115e84edbc76d316759e206580a06c6973 ]

The sense data buffer in sense_buf_pool is allocated with size of
MPT_SENSE_BUFFER_ALLOC(64) (multiplied by req_depth) while SNS_LEN(sc)(96)
is used when reading the data.  That may lead to a read from unallocated
area, sometimes from another (unallocated) page.  To fix this, limit the
read size to MPT_SENSE_BUFFER_ALLOC.

Link: https://lore.kernel.org/r/20200616150446.4840-1-thenzl@redhat.com
Co-developed-by: Stanislav Saner <ssaner@redhat.com>
Signed-off-by: Stanislav Saner <ssaner@redhat.com>
Signed-off-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/message/fusion/mptscsih.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/message/fusion/mptscsih.c b/drivers/message/fusion/mptscsih.c
index 6ba07c7feb92b..2af7ae13449d3 100644
--- a/drivers/message/fusion/mptscsih.c
+++ b/drivers/message/fusion/mptscsih.c
@@ -118,8 +118,6 @@ int 		mptscsih_suspend(struct pci_dev *pdev, pm_message_t state);
 int 		mptscsih_resume(struct pci_dev *pdev);
 #endif
 
-#define SNS_LEN(scp)	SCSI_SENSE_BUFFERSIZE
-
 
 /*=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=*/
 /*
@@ -2420,7 +2418,7 @@ mptscsih_copy_sense_data(struct scsi_cmnd *sc, MPT_SCSI_HOST *hd, MPT_FRAME_HDR
 		/* Copy the sense received into the scsi command block. */
 		req_index = le16_to_cpu(mf->u.frame.hwhdr.msgctxu.fld.req_idx);
 		sense_data = ((u8 *)ioc->sense_buf_pool + (req_index * MPT_SENSE_BUFFER_ALLOC));
-		memcpy(sc->sense_buffer, sense_data, SNS_LEN(sc));
+		memcpy(sc->sense_buffer, sense_data, MPT_SENSE_BUFFER_ALLOC);
 
 		/* Log SMART data (asc = 0x5D, non-IM case only) if required.
 		 */
-- 
2.25.1

[PATCH AUTOSEL 4.14 15/17] nvme-rdma: assign completion vector correctly

[Sasha Levin]

From: Max Gurtovoy <maxg@mellanox.com>

[ Upstream commit 032a9966a22a3596addf81dacf0c1736dfedc32a ]

The completion vector index that is given during CQ creation can't
exceed the number of support vectors by the underlying RDMA device. This
violation currently can accure, for example, in case one will try to
connect with N regular read/write queues and M poll queues and the sum
of N + M > num_supported_vectors. This will lead to failure in establish
a connection to remote target. Instead, in that case, share a completion
vector between queues.

Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/nvme/host/rdma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index 9fffe41ead500..c91bfd839cabe 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -470,7 +470,7 @@ static int nvme_rdma_create_queue_ib(struct nvme_rdma_queue *queue)
 	 * Spread I/O queues completion vectors according their queue index.
 	 * Admin queues can always go on completion vector 0.
 	 */
-	comp_vector = idx == 0 ? idx : idx - 1;
+	comp_vector = (idx == 0 ? idx : idx - 1) % ibdev->num_comp_vectors;
 
 	/* +1 for ib_stop_cq */
 	queue->ib_cq = ib_alloc_cq(ibdev, queue,
-- 
2.25.1

[PATCH AUTOSEL 4.14 16/17] x86/entry: Increase entry_stack size to a full page

[Sasha Levin]

From: Peter Zijlstra <peterz@infradead.org>

[ Upstream commit c7aadc09321d8f9a1d3bd1e6d8a47222ecddf6c5 ]

Marco crashed in bad_iret with a Clang11/KCSAN build due to
overflowing the stack. Now that we run C code on it, expand it to a
full page.

Suggested-by: Andy Lutomirski <luto@amacapital.net>
Reported-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Tested-by: Marco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20200618144801.819246178@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/include/asm/processor.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 6a87eda9691e4..56a89519dc144 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -344,7 +344,7 @@ struct x86_hw_tss {
 #define INVALID_IO_BITMAP_OFFSET	0x8000
 
 struct entry_stack {
-	unsigned long		words[64];
+	char	stack[PAGE_SIZE];
 };
 
 struct entry_stack_page {
-- 
2.25.1

[PATCH AUTOSEL 4.14 17/17] kgdb: Avoid suspicious RCU usage warning

[Sasha Levin]

From: Douglas Anderson <dianders@chromium.org>

[ Upstream commit 440ab9e10e2e6e5fd677473ee6f9e3af0f6904d6 ]

At times when I'm using kgdb I see a splat on my console about
suspicious RCU usage.  I managed to come up with a case that could
reproduce this that looked like this:

  WARNING: suspicious RCU usage
  5.7.0-rc4+ #609 Not tainted
  -----------------------------
  kernel/pid.c:395 find_task_by_pid_ns() needs rcu_read_lock() protection!

  other info that might help us debug this:

    rcu_scheduler_active = 2, debug_locks = 1
  3 locks held by swapper/0/1:
   #0: ffffff81b6b8e988 (&dev->mutex){....}-{3:3}, at: __device_attach+0x40/0x13c
   #1: ffffffd01109e9e8 (dbg_master_lock){....}-{2:2}, at: kgdb_cpu_enter+0x20c/0x7ac
   #2: ffffffd01109ea90 (dbg_slave_lock){....}-{2:2}, at: kgdb_cpu_enter+0x3ec/0x7ac

  stack backtrace:
  CPU: 7 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc4+ #609
  Hardware name: Google Cheza (rev3+) (DT)
  Call trace:
   dump_backtrace+0x0/0x1b8
   show_stack+0x1c/0x24
   dump_stack+0xd4/0x134
   lockdep_rcu_suspicious+0xf0/0x100
   find_task_by_pid_ns+0x5c/0x80
   getthread+0x8c/0xb0
   gdb_serial_stub+0x9d4/0xd04
   kgdb_cpu_enter+0x284/0x7ac
   kgdb_handle_exception+0x174/0x20c
   kgdb_brk_fn+0x24/0x30
   call_break_hook+0x6c/0x7c
   brk_handler+0x20/0x5c
   do_debug_exception+0x1c8/0x22c
   el1_sync_handler+0x3c/0xe4
   el1_sync+0x7c/0x100
   rpmh_rsc_probe+0x38/0x420
   platform_drv_probe+0x94/0xb4
   really_probe+0x134/0x300
   driver_probe_device+0x68/0x100
   __device_attach_driver+0x90/0xa8
   bus_for_each_drv+0x84/0xcc
   __device_attach+0xb4/0x13c
   device_initial_probe+0x18/0x20
   bus_probe_device+0x38/0x98
   device_add+0x38c/0x420

If I understand properly we should just be able to blanket kgdb under
one big RCU read lock and the problem should go away.  We'll add it to
the beast-of-a-function known as kgdb_cpu_enter().

With this I no longer get any splats and things seem to work fine.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200602154729.v2.1.I70e0d4fd46d5ed2aaf0c98a355e8e1b7a5bb7e4e@changeid
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/debug/debug_core.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 159a53ff27162..694fcd0492827 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -489,6 +489,7 @@ static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs,
 		arch_kgdb_ops.disable_hw_break(regs);
 
 acquirelock:
+	rcu_read_lock();
 	/*
 	 * Interrupts will be restored by the 'trap return' code, except when
 	 * single stepping.
@@ -545,6 +546,7 @@ static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs,
 			atomic_dec(&slaves_in_kgdb);
 			dbg_touch_watchdogs();
 			local_irq_restore(flags);
+			rcu_read_unlock();
 			return 0;
 		}
 		cpu_relax();
@@ -563,6 +565,7 @@ static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs,
 		raw_spin_unlock(&dbg_master_lock);
 		dbg_touch_watchdogs();
 		local_irq_restore(flags);
+		rcu_read_unlock();
 
 		goto acquirelock;
 	}
@@ -682,6 +685,7 @@ static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs,
 	raw_spin_unlock(&dbg_master_lock);
 	dbg_touch_watchdogs();
 	local_irq_restore(flags);
+	rcu_read_unlock();
 
 	return kgdb_info[cpu].ret_state;
 }
-- 
2.25.1