From: Manaf Meethalavalappu Pallikunhi manafm@codeaurora.org
[ Upstream commit 2046a24ae121cd107929655a6aaf3b8c5beea01f ]
There is a possible chance that some cooling device stats buffer allocation fails due to very high cooling device max state value. Later cooling device update sysfs can try to access stats data for the same cooling device. It will lead to NULL pointer dereference issue.
Add a NULL pointer check before accessing thermal cooling device stats data. It fixes the following bug
[ 26.812833] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004 [ 27.122960] Call trace: [ 27.122963] do_raw_spin_lock+0x18/0xe8 [ 27.122966] _raw_spin_lock+0x24/0x30 [ 27.128157] thermal_cooling_device_stats_update+0x24/0x98 [ 27.128162] cur_state_store+0x88/0xb8 [ 27.128166] dev_attr_store+0x40/0x58 [ 27.128169] sysfs_kf_write+0x50/0x68 [ 27.133358] kernfs_fop_write+0x12c/0x1c8 [ 27.133362] __vfs_write+0x54/0x160 [ 27.152297] vfs_write+0xcc/0x188 [ 27.157132] ksys_write+0x78/0x108 [ 27.162050] ksys_write+0xf8/0x108 [ 27.166968] __arm_smccc_hvc+0x158/0x4b0 [ 27.166973] __arm_smccc_hvc+0x9c/0x4b0 [ 27.186005] el0_svc+0x8/0xc
Signed-off-by: Manaf Meethalavalappu Pallikunhi manafm@codeaurora.org Signed-off-by: Daniel Lezcano daniel.lezcano@linaro.org Link: https://lore.kernel.org/r/1607367181-24589-1-git-send-email-manafm@codeauror... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/thermal/thermal_sysfs.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c index 0866e949339b..9b73532464e5 100644 --- a/drivers/thermal/thermal_sysfs.c +++ b/drivers/thermal/thermal_sysfs.c @@ -754,6 +754,9 @@ void thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev, { struct cooling_dev_stats *stats = cdev->stats;
+ if (!stats) + return; + spin_lock(&stats->lock);
if (stats->state == new_state)