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authorChristian König <christian.koenig@amd.com>2021-01-15 16:32:39 +0300
committerChristian König <christian.koenig@amd.com>2021-01-20 17:05:45 +0300
commit7621350c6bb20fb6ab7eb988833ab96eac3dcbef (patch)
tree24929d0358a69f7b0a0f65cfa09b41b4687c2ed8 /drivers/gpu/drm/drm_syncobj.c
parentf987c9e0f537222e90dd3214bfc481860fe2abe0 (diff)
downloadlinux-7621350c6bb20fb6ab7eb988833ab96eac3dcbef.tar.xz
drm/syncobj: make lockdep complain on WAIT_FOR_SUBMIT v3
DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT can't be used when we hold locks since we are basically waiting for userspace to do something. Holding a lock while doing so can trivial deadlock with page faults etc... So make lockdep complain when a driver tries to do this. v2: Add lockdep_assert_none_held() macro. v3: Add might_sleep() and also use lockdep_assert_none_held() in the IOCTL path. Signed-off-by: Christian König <christian.koenig@amd.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patchwork.freedesktop.org/patch/414944/
Diffstat (limited to 'drivers/gpu/drm/drm_syncobj.c')
-rw-r--r--drivers/gpu/drm/drm_syncobj.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index 6e74e6745eca..9ecfec1e5567 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -387,6 +387,15 @@ int drm_syncobj_find_fence(struct drm_file *file_private,
if (!syncobj)
return -ENOENT;
+ /* Waiting for userspace with locks help is illegal cause that can
+ * trivial deadlock with page faults for example. Make lockdep complain
+ * about it early on.
+ */
+ if (flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT) {
+ might_sleep();
+ lockdep_assert_none_held_once();
+ }
+
*fence = drm_syncobj_fence_get(syncobj);
drm_syncobj_put(syncobj);
@@ -940,6 +949,9 @@ static signed long drm_syncobj_array_wait_timeout(struct drm_syncobj **syncobjs,
uint64_t *points;
uint32_t signaled_count, i;
+ if (flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT)
+ lockdep_assert_none_held_once();
+
points = kmalloc_array(count, sizeof(*points), GFP_KERNEL);
if (points == NULL)
return -ENOMEM;