From 94ee682ce7914a734b7e0f3e5da6d349d54df515 Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Wed, 17 Nov 2021 10:45:25 +0100 Subject: [PATCH] drm/vc4: kms: Clear the HVS FIFO commit pointer once done Commit 773085fb64df ("drm/vc4: kms: Wait on previous FIFO users before a commit") introduced a wait on the previous commit done on a given HVS FIFO. However, we never cleared that pointer once done. Since drm_crtc_commit_put can free the drm_crtc_commit structure directly if we were the last user, this means that it can lead to a use-after free if we were to duplicate the state, and that stale pointer would even be copied to the new state. Set the pointer to NULL once we're done with the wait so that we don't carry over a pointer to a free'd structure. Fixes: 773085fb64df ("drm/vc4: kms: Wait on previous FIFO users before a commit") Signed-off-by: Maxime Ripard Reviewed-by: Dave Stevenson Tested-by: Jian-Hong Pan Link: https://lore.kernel.org/r/20211117094527.146275-5-maxime@cerno.tech --- drivers/gpu/drm/vc4/vc4_kms.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c index 7c1d0c3beba2e..f80370e87e98e 100644 --- a/drivers/gpu/drm/vc4/vc4_kms.c +++ b/drivers/gpu/drm/vc4/vc4_kms.c @@ -379,6 +379,7 @@ static void vc4_atomic_commit_tail(struct drm_atomic_state *state) drm_err(dev, "Timed out waiting for commit\n"); drm_crtc_commit_put(commit); + old_hvs_state->fifo_state[channel].pending_commit = NULL; } if (vc4->hvs->hvs5) -- 2.39.5