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> # 4.19.y and 5.4.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 4.19.y/5.4.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 14be09537109..a80d6de3c8ad 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -12,6 +12,12 @@
#if GCC_VERSION < 40600
# 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
/*
--
2.30.0.284.gd98b1dd5eaa7-goog
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