This is a note to let you know that I've just added the patch titled
drm: damage_helper: Fix race checking plane->state->fb
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-damage_helper-fix-race-checking-plane-state-fb.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
From 354c2d310082d1c384213ba76c3757dd3cd8755d Mon Sep 17 00:00:00 2001
From: Sean Paul <[email protected]>
Date: Wed, 4 Sep 2019 16:29:13 -0400
Subject: drm: damage_helper: Fix race checking plane->state->fb
From: Sean Paul <[email protected]>
commit 354c2d310082d1c384213ba76c3757dd3cd8755d upstream.
Since the dirtyfb ioctl doesn't give us any hints as to which plane is
scanning out the fb it's marking as damaged, we need to loop through
planes to find it.
Currently we just reach into plane state and check, but that can race
with another commit changing the fb out from under us. This patch locks
the plane before checking the fb and will release the lock if the plane
is not displaying the dirty fb.
Fixes: b9fc5e01d1ce ("drm: Add helper to implement legacy dirtyfb")
Cc: Rob Clark <[email protected]>
Cc: Deepak Rawat <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: Thomas Hellstrom <[email protected]>
Cc: Maarten Lankhorst <[email protected]>
Cc: Maxime Ripard <[email protected]>
Cc: Sean Paul <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: [email protected]
Cc: <[email protected]> # v5.0+
Reported-by: Daniel Vetter <[email protected]>
Reviewed-by: Daniel Vetter <[email protected]>
Signed-off-by: Sean Paul <[email protected]>
Link:
https://patchwork.freedesktop.org/patch/msgid/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/gpu/drm/drm_damage_helper.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/drivers/gpu/drm/drm_damage_helper.c
+++ b/drivers/gpu/drm/drm_damage_helper.c
@@ -212,8 +212,14 @@ retry:
drm_for_each_plane(plane, fb->dev) {
struct drm_plane_state *plane_state;
- if (plane->state->fb != fb)
+ ret = drm_modeset_lock(&plane->mutex, state->acquire_ctx);
+ if (ret)
+ goto out;
+
+ if (plane->state->fb != fb) {
+ drm_modeset_unlock(&plane->mutex);
continue;
+ }
plane_state = drm_atomic_get_plane_state(state, plane);
if (IS_ERR(plane_state)) {
Patches currently in stable-queue which might be from [email protected] are
queue-5.4/drm-msm-fix-memleak-on-release.patch
queue-5.4/drm-damage_helper-fix-race-checking-plane-state-fb.patch
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