Hans Verkuil <hverkuil@xxxxxxxxx> 于2023年3月13日周一 21:17写道： > > On 07/03/2023 16:35, 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..cf00ccaa7829 100644 > > --- a/drivers/media/platform/verisilicon/hantro_drv.c > > +++ b/drivers/media/platform/verisilicon/hantro_drv.c > > @@ -601,6 +601,7 @@ static int hantro_release(struct file *filp) > > * No need for extra locking because this was the last reference > > * to this file. > > */ > > + cancel_delayed_work(&vpu->watchdog_work); > > v4l2_m2m_ctx_release(ctx->fh.m2m_ctx); > > v4l2_fh_del(&ctx->fh); > > v4l2_fh_exit(&ctx->fh); > > drivers/media/platform/verisilicon/hantro_drv.c: In function ‘hantro_release’: > drivers/media/platform/verisilicon/hantro_drv.c:604:30: error: ‘vpu’ undeclared (first use in this function); did you mean ‘fpu’? > 604 | cancel_delayed_work(&vpu->watchdog_work); > | ^~~ > | fpu > drivers/media/platform/verisilicon/hantro_drv.c:604:30: note: each undeclared identifier is reported only once for each function it appears in > > You clearly didn't compile this patch! > Sorry for my mistake. I was hurried to report the issue and discuss with developer to confirm it . I'll complete it and test it locally. Best regards, Zheng
