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@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); > -- regards, Stan
