While reviewing Christian's annotation patch I noticed that we have a
user-after-free for the WAIT_FOR_SUBMIT case: We drop the syncobj
reference before we've completed the waiting.
Of course usually there's nothing bad happening here since userspace
keeps the reference, but we can't rely on userspace to play nice here!
Signed-off-by: Daniel Vetter <daniel.vetter(a)intel.com>
Fixes: bc9c80fe01a2 ("drm/syncobj: use the timeline point in drm_syncobj_find_fence v4")
Cc: Christian König <christian.koenig(a)amd.com>
Cc: Lionel Landwerlin <lionel.g.landwerlin(a)intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst(a)linux.intel.com>
Cc: Maxime Ripard <mripard(a)kernel.org>
Cc: Thomas Zimmermann <tzimmermann(a)suse.de>
Cc: David Airlie <airlied(a)linux.ie>
Cc: Daniel Vetter <daniel(a)ffwll.ch>
Cc: dri-devel(a)lists.freedesktop.org
Cc: <stable(a)vger.kernel.org> # v5.2+
---
drivers/gpu/drm/drm_syncobj.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index 6e74e6745eca..349146049849 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -388,19 +388,18 @@ int drm_syncobj_find_fence(struct drm_file *file_private,
return -ENOENT;
*fence = drm_syncobj_fence_get(syncobj);
- drm_syncobj_put(syncobj);
if (*fence) {
ret = dma_fence_chain_find_seqno(fence, point);
if (!ret)
- return 0;
+ goto out;
dma_fence_put(*fence);
} else {
ret = -EINVAL;
}
if (!(flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT))
- return ret;
+ goto out;
memset(&wait, 0, sizeof(wait));
wait.task = current;
@@ -432,6 +431,9 @@ int drm_syncobj_find_fence(struct drm_file *file_private,
if (wait.node.next)
drm_syncobj_remove_wait(syncobj, &wait);
+out:
+ drm_syncobj_put(syncobj);
+
return ret;
}
EXPORT_SYMBOL(drm_syncobj_find_fence);
--
2.30.0
If we enable_breadcrumbs for a request while that request is being
removed from HW; we may see that the request is active as we take the
ce->signal_lock and proceed to attach the request to ce->signals.
However, during unsubmission after marking the request as inactive, we
see that the request has not yet been added to ce->signals and so skip
the removal. Pull the check during cancel_breadcrumbs under the same
spinlock as enabling so that we the two tests are consistent in
enable/cancel.
Otherwise, we may insert a request onto ce->signal that we expect should
not be there:
intel_context_remove_breadcrumbs:488 GEM_BUG_ON(!__i915_request_is_complete(rq))
While updating, we can note that we are always called with
irqs-disabled, due to the engine->active.lock being held at the single
caller, and so remove the irqsave/restore.
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2931
Fixes: c18636f76344 ("drm/i915: Remove requirement for holding i915_request.lock for breadcrumbs")
Signed-off-by: Chris Wilson <chris(a)chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin(a)intel.com>
Cc: Andi Shyti <andi.shyti(a)intel.com>
Cc: <stable(a)vger.kernel.org> # v5.10+
---
drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
index d098fc0c14ec..34a645d6babd 100644
--- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
+++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
@@ -453,16 +453,17 @@ void i915_request_cancel_breadcrumb(struct i915_request *rq)
{
struct intel_breadcrumbs *b = READ_ONCE(rq->engine)->breadcrumbs;
struct intel_context *ce = rq->context;
- unsigned long flags;
bool release;
- if (!test_and_clear_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags))
+ spin_lock(&ce->signal_lock);
+ if (!test_and_clear_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags)) {
+ spin_unlock(&ce->signal_lock);
return;
+ }
- spin_lock_irqsave(&ce->signal_lock, flags);
list_del_rcu(&rq->signal_link);
release = remove_signaling_context(b, ce);
- spin_unlock_irqrestore(&ce->signal_lock, flags);
+ spin_unlock(&ce->signal_lock);
if (release)
intel_context_put(ce);
--
2.20.1
commit dca5244d2f5b94f1809f0c02a549edf41ccd5493 upstream.
GCC versions >= 4.9 and < 5.1 have been shown to emit memory references
beyond the stack pointer, resulting in memory corruption if an interrupt
is taken after the stack pointer has been adjusted but before the
reference has been executed. This leads to subtle, infrequent data
corruption such as the EXT4 problems reported by Russell King at the
link below.
Life is too short for buggy compilers, so raise the minimum GCC version
required by arm64 to 5.1.
Reported-by: Russell King <linux(a)armlinux.org.uk>
Suggested-by: Arnd Bergmann <arnd(a)kernel.org>
Signed-off-by: Will Deacon <will(a)kernel.org>
Tested-by: Nathan Chancellor <natechancellor(a)gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers(a)google.com>
Reviewed-by: Nathan Chancellor <natechancellor(a)gmail.com>
Acked-by: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: <stable(a)vger.kernel.org> # 4.4.y, 4.9.y and 4.14.y only
Cc: Theodore Ts'o <tytso(a)mit.edu>
Cc: Florian Weimer <fweimer(a)redhat.com>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Nick Desaulniers <ndesaulniers(a)google.com>
Link: https://lore.kernel.org/r/20210105154726.GD1551@shell.armlinux.org.uk
Link: https://lore.kernel.org/r/20210112224832.10980-1-will@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas(a)arm.com>
[will: backport to 4.4.y/4.9.y/4.14.y]
Signed-off-by: Will Deacon <will(a)kernel.org>
---
include/linux/compiler-gcc.h | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index af8b4a879934..3cc8adede67b 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -145,6 +145,12 @@
#if GCC_VERSION < 30200
# error Sorry, your compiler is too old - please upgrade it.
+#elif defined(CONFIG_ARM64) && GCC_VERSION < 50100
+/*
+ * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63293
+ * https://lore.kernel.org/r/20210107111841.GN1551@shell.armlinux.org.uk
+ */
+# error Sorry, your version of GCC is too old - please use 5.1 or newer.
#endif
#if GCC_VERSION < 30300
--
2.30.0.284.gd98b1dd5eaa7-goog