The following commit has been merged into the x86/core branch of tip:
Commit-ID: ce3ba2af9695e4bd64d797e0026321e5dca29dd3
Gitweb: https://git.kernel.org/tip/ce3ba2af9695e4bd64d797e0026321e5dca29dd3
Author: Alexander Potapenko <glider@xxxxxxxxxx>
AuthorDate: Fri, 18 Nov 2022 18:23:05 +01:00
Committer: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
CommitterDate: Fri, 27 Jan 2023 09:00:56 -08:00
x86: Suppress KMSAN reports in arch_within_stack_frames()
arch_within_stack_frames() performs stack walking and may confuse
KMSAN by stepping on stale shadow values. To prevent false positive
reports, disable KMSAN checks in this function.
This fixes KMSAN's interoperability with CONFIG_HARDENED_USERCOPY.
Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Tested-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Link: https://github.com/google/kmsan/issues/89
Link: https://lore.kernel.org/lkml/Y3b9AAEKp2Vr3e6O@sol.localdomain/
Link: https://lore.kernel.org/all/20221118172305.3321253-1-glider%40google.com
---
arch/x86/include/asm/thread_info.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index f0cb881..f1cccba 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -163,7 +163,12 @@ struct thread_info {
* GOOD_FRAME if within a frame
* BAD_STACK if placed across a frame boundary (or outside stack)
* NOT_STACK unable to determine (no frame pointers, etc)
+ *
+ * This function reads pointers from the stack and dereferences them. The
+ * pointers may not have their KMSAN shadow set up properly, which may result
+ * in false positive reports. Disable instrumentation to avoid those.
*/
+__no_kmsan_checks
static inline int arch_within_stack_frames(const void * const stack,
const void * const stackend,
const void *obj, unsigned long len)
|