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Thank you all!
Regards,
Lingkai
From: Christian König <christian.koenig@xxxxxxx>
Sent: Thursday, December 7, 2023 1:55 PM To: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx>; Linus Walleij <linus.walleij@xxxxxxxxxx>; Lingkai Dong <Lingkai.Dong@xxxxxxx>; Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> Cc: nd <nd@xxxxxxx>; dri-devel@xxxxxxxxxxxxxxxxxxxxx <dri-devel@xxxxxxxxxxxxxxxxxxxxx> Subject: Re: [PATCH] drm: Fix FD ownership check in drm_master_check_perm() Am 07.12.23 um 11:22 schrieb Tvrtko Ursulin:
> > > On 07/12/2023 10:18, Christian König wrote: >> Am 07.12.23 um 11:12 schrieb Linus Walleij: >>> On Wed, Dec 6, 2023 at 2:52 PM Lingkai Dong <Lingkai.Dong@xxxxxxx> >>> wrote: >>> >>>> The DRM subsystem keeps a record of the owner of a DRM device file >>>> descriptor using thread group ID (TGID) instead of process ID >>>> (PID), to >>>> ensures all threads within the same userspace process are >>>> considered the >>>> owner. However, the DRM master ownership check compares the current >>>> thread's PID against the record, so the thread is incorrectly >>>> considered to >>>> be not the FD owner if the PID is not equal to the TGID. This >>>> causes DRM >>>> ioctls to be denied master privileges, even if the same thread that >>>> opened >>>> the FD performs an ioctl. Fix this by checking TGID. >>>> >>>> Fixes: 4230cea89cafb ("drm: Track clients by tgid and not tid") >>>> Signed-off-by: Lingkai Dong <lingkai.dong@xxxxxxx> >>> Paging the patch author (Tvrko) and committer (Christian). >>> Here is the patch if you don't have it in your mailbox: >>> https://lore.kernel.org/dri-devel/PA6PR08MB107665920BE9A96658CDA04CE8884A@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ >>> >>> >>> I'm seeing this as well (on Android). >>> >>> Tvrko, Christian: can you look at this? >> >> Good catch, looks like we missed this occasion while switching from >> PID to TGID. > > Oops, yes.. > > Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > >>> Will you apply it to the AMD tree for fixes if it looks OK >>> or does it go elsewhere? >> >> I can push this to drm-misc-fixes as long as nobody objects in the >> next hour or so. >> >> CC: stable? If yes which versions? > > Cc: <stable@xxxxxxxxxxxxxxx> # v6.4+ And pushed to drm-misc-fixes. Thanks, Christian. > > Regards, > > Tvrtko |
