* [PATCH] spi: Fix potential NULL pointer dereference in spi_shutdown()
[not found] <CGME20201124131532eucas1p22f02c41a48e9768738b4529771ed7820@eucas1p2.samsung.com>
@ 2020-11-24 13:15 ` Marek Szyprowski
0 siblings, 0 replies; only message in thread
From: Marek Szyprowski @ 2020-11-24 13:15 UTC (permalink / raw)
To: linux-spi, linux-kernel
Cc: Marek Szyprowski, Mark Brown, Uwe Kleine-König,
Greg Kroah-Hartman, Bartlomiej Zolnierkiewicz
Shutdown bus function might be called on the unbound device, so add a
check if there is a driver before calling its shutdown function.
This fixes following kernel panic obserbed during system reboot:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000018
...
Call trace:
spi_shutdown+0x10/0x38
kernel_restart_prepare+0x34/0x40
kernel_restart+0x14/0x88
__do_sys_reboot+0x148/0x248
__arm64_sys_reboot+0x1c/0x28
el0_svc_common.constprop.3+0x74/0x198
do_el0_svc+0x20/0x98
el0_sync_handler+0x140/0x1a8
el0_sync+0x140/0x180
Code: f9403402 d1008041 f100005f 9a9f1021 (f9400c21)
---[ end trace 266c07205a2d632e ]---
Fixes: 9db34ee64ce4 ("spi: Use bus_type functions for probe, remove and shutdown)"
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
drivers/spi/spi.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 0c3f3a962448..cd3c395b4e90 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -426,10 +426,12 @@ static int spi_remove(struct device *dev)
static void spi_shutdown(struct device *dev)
{
- const struct spi_driver *sdrv = to_spi_driver(dev->driver);
+ if (dev->driver) {
+ const struct spi_driver *sdrv = to_spi_driver(dev->driver);
- if (sdrv->shutdown)
- sdrv->shutdown(to_spi_device(dev));
+ if (sdrv->shutdown)
+ sdrv->shutdown(to_spi_device(dev));
+ }
}
struct bus_type spi_bus_type = {
--
2.17.1
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2020-11-24 13:15 ` [PATCH] spi: Fix potential NULL pointer dereference in spi_shutdown() Marek Szyprowski
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