[PATCH mm] fix for "kasan, vmalloc: only tag normal vmalloc allocations"

[andrey . konovalov]

From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>

"kasan, vmalloc: only tag normal vmalloc allocations" unintentionally
disabled poisoning of executable memory for the Generic mode. Fix it.

Reported-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
---
 mm/kasan/shadow.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c
index 7272e248db87..a4f07de21771 100644
--- a/mm/kasan/shadow.c
+++ b/mm/kasan/shadow.c
@@ -489,10 +489,11 @@ void *__kasan_unpoison_vmalloc(const void *start, unsigned long size,
 		return (void *)start;
 
 	/*
-	 * Don't tag executable memory.
+	 * Don't tag executable memory with the tag-based mode.
 	 * The kernel doesn't tolerate having the PC register tagged.
 	 */
-	if (!(flags & KASAN_VMALLOC_PROT_NORMAL))
+	if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) &&
+	    !(flags & KASAN_VMALLOC_PROT_NORMAL))
 		return (void *)start;
 
 	start = set_tag(start, kasan_random_tag());
-- 
2.25.1