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| author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2017-05-22 15:59:45 +0200 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2017-05-23 09:39:14 +0200 |
| commit | f928543404bdf6bb4e8d6a6c3ced5edebd0d6f38 (patch) | |
| tree | e467518f1cc1b361a99cfc5cb8bcab1733a530f9 /drivers/gpu/drm/drm_plane.c | |
| parent | 429030bc944ee9a8bbe5d9bb23dcda0ae2205450 (diff) | |
| download | linux-f928543404bdf6bb4e8d6a6c3ced5edebd0d6f38.tar.bz2 | |
drm: Fix deadlock retry loop in page_flip_ioctl
I failed to properly onion-wrap the unwind code: We acquire the vblank
reference before we start with the wait-wound locking dance, hence we
must make sure we retry before we drop the reference. Oops.
v2: The vblank_put must be after the frambuffer_put (Michel). I suck at
unwrapping code that doesn't use separate labels for each stage, but
checks each pointer first ... While re-reading everything I also
realized that we must clean up the fb refcounts, and specifically
plane->old_fb before we drop the locks, either in the final unlocking,
or in the w/w retry path. Hence the correct fix is to drop the
vblank_put to the very bottom.
Fixes: 29dc0d1de182 ("drm: Roll out acquire context for the page_flip ioctl")
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
Reported-by: Tommi Rantala <tt.rantala@gmail.com>
Cc: Tommi Rantala <tt.rantala@gmail.com>
Cc: Michel Dänzer <michel@daenzer.net>
Tested-by: Tommi Rantala <tt.rantala@gmail.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170522135945.28831-1-daniel.vetter@ffwll.ch
Diffstat (limited to 'drivers/gpu/drm/drm_plane.c')
| -rw-r--r-- | drivers/gpu/drm/drm_plane.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c index fedd4d60d9cd..5dc8c4350602 100644 --- a/drivers/gpu/drm/drm_plane.c +++ b/drivers/gpu/drm/drm_plane.c @@ -948,8 +948,6 @@ retry: } out: - if (ret && crtc->funcs->page_flip_target) - drm_crtc_vblank_put(crtc); if (fb) drm_framebuffer_put(fb); if (crtc->primary->old_fb) @@ -964,5 +962,8 @@ out: drm_modeset_drop_locks(&ctx); drm_modeset_acquire_fini(&ctx); + if (ret && crtc->funcs->page_flip_target) + drm_crtc_vblank_put(crtc); + return ret; } |