On 13/03/2023 16:08, Hans Verkuil wrote: > On 07/03/2023 16:41, Zheng Wang wrote: >> In hantro_probe, vpu->watchdog_work is bound with >> hantro_watchdog. Then hantro_end_prepare_run may >> be called to start the work. >> >> If we close the file or remove the module which will >> call hantro_release and hantro_remove to make cleanup, >> there may be a unfinished work. The possible sequence >> is as follows, which will cause a typical UAF bug. >> >> The same thing will happen in hantro_release, and use >> ctx after freeing it. >> >> Fix it by canceling the work before cleanup in hantro_release. >> >> CPU0 CPU1 >> >> |hantro_watchdog >> hantro_remove | >> v4l2_m2m_release | >> kfree(m2m_dev); | >> | >> | v4l2_m2m_get_curr_priv >> | m2m_dev->curr_ctx //use >> >> Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx> >> --- >> drivers/media/platform/verisilicon/hantro_drv.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/media/platform/verisilicon/hantro_drv.c b/drivers/media/platform/verisilicon/hantro_drv.c >> index b0aeedae7b65..80bd856a4da9 100644 >> --- a/drivers/media/platform/verisilicon/hantro_drv.c >> +++ b/drivers/media/platform/verisilicon/hantro_drv.c >> @@ -1099,6 +1099,7 @@ static int hantro_remove(struct platform_device *pdev) >> >> v4l2_info(&vpu->v4l2_dev, "Removing %s\n", pdev->name); >> >> + cancel_delayed_work(&vpu->watchdog_work); > > Use cancel_delayed_work_sync(): that ensures the code waits for a running > watchdog function to finish. > > Ditto for the other patch. And also the cedrus and rkvdec patches. Regards, Hans > > Regards, > > Hans > >> media_device_unregister(&vpu->mdev); >> hantro_remove_dec_func(vpu); >> hantro_remove_enc_func(vpu); >
