[v6,09/18] khwasan, arm64: fix up fault handling logic

Commit Message

Andrey Konovalov Aug. 29, 2018, 11:35 a.m. UTC

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 KHWASAN enabled.
Reset the top byte.

Signed-off-by: Andrey Konovalov <[e-mail]>
---
 arch/arm64/mm/fault.c | 3 +++
 1 file changed, 3 insertions(+)

Patch

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 50b30ff30de4..35feee78a9bd 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>
@@ -134,6 +135,8 @@  void show_pte(unsigned long addr)
 	pgd_t *pgdp;
 	pgd_t pgd;
 
+	addr = (unsigned long)khwasan_reset_tag((void *)addr);
+
 	if (addr < TASK_SIZE) {
 		/* TTBR0 */
 		mm = current->active_mm;