diff options
| author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2024-07-10 11:31:16 +0200 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2024-07-18 15:39:54 +0200 |
| commit | 99e0fb8b087120b5a7019f1cff6c5c2b5b925ae5 (patch) | |
| tree | 2077ad54c9af61c514f318aad3f04b57a18ef597 /drivers/gpu/drm/drm_mode_config.c | |
| parent | ca5442ed8f5383f86bb9b4d66eeb816cd90aeb3b (diff) | |
drm: Add might_fault to drm_modeset_lock priming
We already teach lockdep that dma_resv nests within drm_modeset_lock,
but there's a lot more: All drm kms ioctl rely on being able to
put/get_user while holding modeset locks, so we really need a
might_fault in there too to complete the picture. Add it.
Motivated by a syzbot report that blew up on bcachefs doing an
unconditional console_lock way deep in the locking hierarchy, and
lockdep only noticing the depency loop in a drm ioctl instead of much
earlier. This annotation will make sure such issues have a much harder
time escaping.
References: https://lore.kernel.org/dri-devel/00000000000073db8b061cd43496@google.com/
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20240710093120.732208-1-daniel.vetter@ffwll.ch
Diffstat (limited to 'drivers/gpu/drm/drm_mode_config.c')
| -rw-r--r-- | drivers/gpu/drm/drm_mode_config.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c index 568972258222..37d2e0a4ef4b 100644 --- a/drivers/gpu/drm/drm_mode_config.c +++ b/drivers/gpu/drm/drm_mode_config.c @@ -456,6 +456,8 @@ int drmm_mode_config_init(struct drm_device *dev) if (ret == -EDEADLK) ret = drm_modeset_backoff(&modeset_ctx); + might_fault(); + ww_acquire_init(&resv_ctx, &reservation_ww_class); ret = dma_resv_lock(&resv, &resv_ctx); if (ret == -EDEADLK) |