diff options
| author | Tuo Li <islituo@gmail.com> | 2023-06-30 10:19:06 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-09-23 10:48:16 +0200 |
| commit | 9ac69bda79677028972098c56fa2e1a5031e1182 (patch) | |
| tree | 9368abfecaf604d39b85ca8e7c998bac3b0b0b01 | |
| parent | 5655ce4038a7f88c46294dcd85d4f64d35814b62 (diff) | |
| download | linux-9ac69bda79677028972098c56fa2e1a5031e1182.tar.gz linux-9ac69bda79677028972098c56fa2e1a5031e1182.tar.bz2 linux-9ac69bda79677028972098c56fa2e1a5031e1182.zip | |
drm/exynos: fix a possible null-pointer dereference due to data race in exynos_drm_crtc_atomic_disable()
[ Upstream commit 2e63972a2de14482d0eae1a03a73e379f1c3f44c ]
The variable crtc->state->event is often protected by the lock
crtc->dev->event_lock when is accessed. However, it is accessed as a
condition of an if statement in exynos_drm_crtc_atomic_disable() without
holding the lock:
if (crtc->state->event && !crtc->state->active)
However, if crtc->state->event is changed to NULL by another thread right
after the conditions of the if statement is checked to be true, a
null-pointer dereference can occur in drm_crtc_send_vblank_event():
e->pipe = pipe;
To fix this possible null-pointer dereference caused by data race, the
spin lock coverage is extended to protect the if statement as well as the
function call to drm_crtc_send_vblank_event().
Reported-by: BassCheck <bass@buaa.edu.cn>
Link: https://sites.google.com/view/basscheck/home
Signed-off-by: Tuo Li <islituo@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Added relevant link.
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/gpu/drm/exynos/exynos_drm_crtc.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/gpu/drm/exynos/exynos_drm_crtc.c b/drivers/gpu/drm/exynos/exynos_drm_crtc.c index 2696289ecc78..b3e23ace5869 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_crtc.c +++ b/drivers/gpu/drm/exynos/exynos_drm_crtc.c @@ -43,13 +43,12 @@ static void exynos_drm_crtc_atomic_disable(struct drm_crtc *crtc, if (exynos_crtc->ops->disable) exynos_crtc->ops->disable(exynos_crtc); + spin_lock_irq(&crtc->dev->event_lock); if (crtc->state->event && !crtc->state->active) { - spin_lock_irq(&crtc->dev->event_lock); drm_crtc_send_vblank_event(crtc, crtc->state->event); - spin_unlock_irq(&crtc->dev->event_lock); - crtc->state->event = NULL; } + spin_unlock_irq(&crtc->dev->event_lock); } static int exynos_crtc_atomic_check(struct drm_crtc *crtc, |