[PATCH 5.10 116/122] drm/syncobj: make lockdep complain on WAIT_FOR_SUBMIT v3
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2024-02-27 14:30:47
Also in:
linux-patches
Subsystem:
drm drivers, drm drivers and misc gpu patches, locking primitives, the rest · Maintainers:
David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Peter Zijlstra, Ingo Molnar, Will Deacon, Boqun Feng, Linus Torvalds
5.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Christian König <christian.koenig@amd.com>
[ Upstream commit 7621350c6bb20fb6ab7eb988833ab96eac3dcbef ]
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 <redacted>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patchwork.freedesktop.org/patch/414944/
Stable-dep-of: 3c43177ffb54 ("drm/syncobj: call drm_syncobj_fence_add_wait when WAIT_AVAILABLE flag is set")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/drm_syncobj.c | 12 ++++++++++++
include/linux/lockdep.h | 5 +++++
2 files changed, 17 insertions(+)
diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index 738e60139db90..4c3c8f8da0215 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); if (*fence) {
@@ -951,6 +960,9 @@ 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;
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 2c2586312b447..3eca9f91b9a56 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h@@ -321,6 +321,10 @@ extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie); WARN_ON_ONCE(debug_locks && !lockdep_is_held(l)); \ } while (0) +#define lockdep_assert_none_held_once() do { \ + WARN_ON_ONCE(debug_locks && current->lockdep_depth); \ + } while (0) + #define lockdep_recursing(tsk) ((tsk)->lockdep_recursion) #define lockdep_pin_lock(l) lock_pin_lock(&(l)->dep_map)
@@ -394,6 +398,7 @@ static inline void lockdep_unregister_key(struct lock_class_key *key) #define lockdep_assert_held_write(l) do { (void)(l); } while (0) #define lockdep_assert_held_read(l) do { (void)(l); } while (0) #define lockdep_assert_held_once(l) do { (void)(l); } while (0) +#define lockdep_assert_none_held_once() do { } while (0) #define lockdep_recursing(tsk) (0)
--
2.43.0