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| author |   Jason-JH Lin <jason-jh.lin@mediatek.com> | 2025-07-28 10:48:50 +0800 |
|---|---|---|
| committer |   Chun-Kuang Hu <chunkuang.hu@kernel.org> | 2025-08-13 23:50:06 +0000 |
| commit | 0c6b24d70da21201ed009a2aca740d2dfddc7ab5 (patch) | |
| tree | 7332bbfa29d61c6074ac43a76f477c97f4d62c2d | |
| parent | Linux 6.17-rc1 (diff) | |
| download | wireguard-linux-0c6b24d70da21201ed009a2aca740d2dfddc7ab5.tar.xz wireguard-linux-0c6b24d70da21201ed009a2aca740d2dfddc7ab5.zip | |
drm/mediatek: Add error handling for old state CRTC in atomic_disable
Introduce error handling to address an issue where, after a hotplug
event, the cursor continues to update. This situation can lead to a
kernel panic due to accessing the NULL `old_state->crtc`.
E,g.
Unable to handle kernel NULL pointer dereference at virtual address
Call trace:
mtk_crtc_plane_disable+0x24/0x140
mtk_plane_atomic_update+0x8c/0xa8
drm_atomic_helper_commit_planes+0x114/0x2c8
drm_atomic_helper_commit_tail_rpm+0x4c/0x158
commit_tail+0xa0/0x168
drm_atomic_helper_commit+0x110/0x120
drm_atomic_commit+0x8c/0xe0
drm_atomic_helper_update_plane+0xd4/0x128
__setplane_atomic+0xcc/0x110
drm_mode_cursor_common+0x250/0x440
drm_mode_cursor_ioctl+0x44/0x70
drm_ioctl+0x264/0x5d8
__arm64_sys_ioctl+0xd8/0x510
invoke_syscall+0x6c/0xe0
do_el0_svc+0x68/0xe8
el0_svc+0x34/0x60
el0t_64_sync_handler+0x1c/0xf8
el0t_64_sync+0x180/0x188
Adding NULL pointer checks to ensure stability by preventing operations
on an invalid CRTC state.
Fixes: d208261e9f7c ("drm/mediatek: Add wait_event_timeout when disabling plane")
Signed-off-by: Jason-JH Lin <jason-jh.lin@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20250728025036.24953-1-jason-jh.lin@mediatek.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
| -rw-r--r-- | drivers/gpu/drm/mediatek/mtk_plane.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/gpu/drm/mediatek/mtk_plane.c b/drivers/gpu/drm/mediatek/mtk_plane.c index cbc4f37da8ba..02349bd44001 100644 --- a/drivers/gpu/drm/mediatek/mtk_plane.c +++ b/drivers/gpu/drm/mediatek/mtk_plane.c @@ -292,7 +292,8 @@ static void mtk_plane_atomic_disable(struct drm_plane *plane, wmb(); /* Make sure the above parameter is set before update */ mtk_plane_state->pending.dirty = true; - mtk_crtc_plane_disable(old_state->crtc, plane); + if (old_state && old_state->crtc) + mtk_crtc_plane_disable(old_state->crtc, plane); } static void mtk_plane_atomic_update(struct drm_plane *plane, |