show_pte in arm64 fault handling relies on the fact that the top byte of
a kernel pointer is 0xff, which isn't always the case with tag-based
KASAN.
This patch resets the top byte in show_pte.
Reviewed-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Reviewed-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
---
arch/arm64/mm/fault.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 7d9571f4ae3d..d9a84d6f3343 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -32,6 +32,7 @@
#include <linux/perf_event.h>
#include <linux/preempt.h>
#include <linux/hugetlb.h>
+#include <linux/kasan.h>
#include <asm/bug.h>
#include <asm/cmpxchg.h>
@@ -141,6 +142,8 @@ void show_pte(unsigned long addr)
pgd_t *pgdp;
pgd_t pgd;
+ addr = (unsigned long)kasan_reset_tag((void *)addr);
+
if (addr < TASK_SIZE) {
/* TTBR0 */
mm = current->active_mm;
--
2.19.1.930.g4563a0d9d0-goog
