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Subject[PATCH v2] media: venus: fix use after free bug in venus_remove due to race condition
Date
in venus_probe, core->work is bound with venus_sys_error_handler, which is
used to handle error. The code use core->sys_err_done to make sync work.
The core->work is started in venus_event_notify.

If we call venus_remove, there might be an unfished work. The possible
sequence is as follows:

CPU0 CPU1

|venus_sys_error_handler
venus_remove |
hfi_destroy |
venus_hfi_destroy |
kfree(hdev); |
|hfi_reinit
|venus_hfi_queues_reinit
|//use hdev

Fix it by canceling the work in venus_remove.

Fixes: af2c3834c8ca ("[media] media: venus: adding core part and helper functions")
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
---
v2:
- add more details to clarify the bug
---
drivers/media/platform/qcom/venus/core.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/media/platform/qcom/venus/core.c b/drivers/media/platform/qcom/venus/core.c
index 990a1519f968..54ace8bf45e7 100644
--- a/drivers/media/platform/qcom/venus/core.c
+++ b/drivers/media/platform/qcom/venus/core.c
@@ -423,6 +423,7 @@ static int venus_remove(struct platform_device *pdev)
struct device *dev = core->dev;
int ret;

+ cancel_delayed_work(&core->work);
ret = pm_runtime_get_sync(dev);
WARN_ON(ret < 0);

--
2.25.1
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