[v2,2/3] venus: core: cancel pending work items in workqueue
diff mbox series

Message ID 1599741856-16239-3-git-send-email-mansur@codeaurora.org
State New, archived
Headers show
Series
  • Venus - Handle race conditions in concurrency
Related show

Commit Message

Mansur Alisha Shaik Sept. 10, 2020, 12:44 p.m. UTC
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]
 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@codeaurora.org>
---
 drivers/media/platform/qcom/venus/core.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Stanimir Varbanov Sept. 11, 2020, 10:22 a.m. UTC | #1
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

>  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@codeaurora.org>
> ---
>  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);
>
Mansur Alisha Shaik Sept. 17, 2020, 1:53 a.m. UTC | #2
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@codeaurora.org>
>> ---
>>  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);
>>

Patch
diff mbox series

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);