On 2020-09-11 15:52, Stanimir Varbanov wrote:
Hi,
On 9/10/20 3:44 PM, Mansur Alisha Shaik wrote:
In concurrency usecase and reboot scenario we are
observing race condition and seeing NULL pointer
dereference crash. In shutdown path and system
recovery path we are destroying the same mutex
hence seeing crash.
This case is handled by mutex protection and
cancel delayed work items in work queue.
Below is the call trace for the crash
Call trace:
venus_remove+0xdc/0xec [venus_core]
venus_core_shutdown+0x1c/0x34 [venus_core]
platform_drv_shutdown+0x28/0x34
device_shutdown+0x154/0x1fc
kernel_restart_prepare+0x40/0x4c
kernel_restart+0x1c/0x64
Call trace:
mutex_lock+0x34/0x60
venus_hfi_destroy+0x28/0x98 [venus_core]
hfi_destroy+0x1c/0x28 [venus_core]
I queued up [1] and after it this cannot happen anymore because
hfi_destroy() is not called by venus_sys_error_handler().
So I guess this patch is not needed anymore.
[1] https://www.spinics.net/lists/linux-arm-msm/msg70092.html
Yes, this patch is not needed any more. rebased and posted new version
https://lore.kernel.org/patchwork/project/lkml/list/?series=463091
venus_sys_error_handler+0x60/0x14c [venus_core]
process_one_work+0x210/0x3d0
worker_thread+0x248/0x3f4
kthread+0x11c/0x12c
ret_from_fork+0x10/0x18
Signed-off-by: Mansur Alisha Shaik <mansur@xxxxxxxxxxxxxx>
---
drivers/media/platform/qcom/venus/core.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/media/platform/qcom/venus/core.c
b/drivers/media/platform/qcom/venus/core.c
index c5af428..69aa199 100644
--- a/drivers/media/platform/qcom/venus/core.c
+++ b/drivers/media/platform/qcom/venus/core.c
@@ -323,6 +323,8 @@ static int venus_remove(struct platform_device
*pdev)
struct device *dev = core->dev;
int ret;
+ cancel_delayed_work_sync(&core->work);
+
ret = pm_runtime_get_sync(dev);
WARN_ON(ret < 0);
@@ -340,7 +342,9 @@ static int venus_remove(struct platform_device
*pdev)
if (pm_ops->core_put)
pm_ops->core_put(dev);
+ mutex_lock(&core->lock);
hfi_destroy(core);
+ mutex_unlock(&core->lock);
icc_put(core->video_path);
icc_put(core->cpucfg_path);
