Hi Lad, Yet again I can not demonstrate you a nice error trace corresponding to the bug fixed by the patch. Indeed, there is a branch in vpif_probe() that explicitly invokes vpif_probe_complete() and the patch targets the possible issue that can happen during this.
When I developed the patch I saw on vpif_display.ko. It looks very similar regarding things touched by the patch. In particular, it does not free vpif_obj.sd in its vpif_probe_complete(). But now I see that it does this in vpif_remove()! Do you think that vpif_capture.ko should do the same? If so, I guess that I should fix the patch appropriately since likely it just replaces one (very rare) bug with another one (on a typical execution path). -- Evgeny Novikov Linux Verification Center, ISP RAS http://linuxtesting.org 24.07.2020, 17:17, "Lad, Prabhakar" <[email protected]>: > Hi Evgeny, > > Thank you for the patch. > > On Thu, Jul 23, 2020 at 6:04 PM Evgeny Novikov <[email protected]> wrote: >> In case of errors vpif_probe_complete() releases memory for vpif_obj.sd >> and unregisters the V4L2 device. But then this is done again by >> vpif_probe() itself. The patch removes the cleaning from >> vpif_probe_complete(). >> >> Found by Linux Driver Verification project (linuxtesting.org). >> >> Signed-off-by: Evgeny Novikov <[email protected]> >> --- >> drivers/media/platform/davinci/vpif_capture.c | 2 -- >> 1 file changed, 2 deletions(-) >> >> diff --git a/drivers/media/platform/davinci/vpif_capture.c >> b/drivers/media/platform/davinci/vpif_capture.c >> index d9ec439faefa..72a0e94e2e21 100644 >> --- a/drivers/media/platform/davinci/vpif_capture.c >> +++ b/drivers/media/platform/davinci/vpif_capture.c >> @@ -1482,8 +1482,6 @@ static int vpif_probe_complete(void) >> /* Unregister video device */ >> video_unregister_device(&ch->video_dev); >> } >> - kfree(vpif_obj.sd); >> - v4l2_device_unregister(&vpif_obj.v4l2_dev); > > vpif_probe_complete() is a async callback and probe() should have > already completed by then. > > Cheers, > --Prabhakar > >> return err; >> } >> -- >> 2.16.4
