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authorVincenzo Frascino <vincenzo.frascino@arm.com>2020-12-10 15:42:12 +1100
committerStephen Rothwell <sfr@canb.auug.org.au>2020-12-16 18:03:00 +1100
commit7867c07d8d2967266458595eeded01ba834f166d (patch)
treeff26c1f19623d5493498a6f63722cdbb1bb2a02f
parentf3cbdd121dc5405a358ee35201f7300e9049cf37 (diff)
downloadlinux-7867c07d8d2967266458595eeded01ba834f166d.tar.gz
kasan, mm: untag page address in free_reserved_area
free_reserved_area() memsets the pages belonging to a given memory area. As that memory hasn't been allocated via page_alloc, the KASAN tags that those pages have are 0x00. As the result the memset might result in a tag mismatch. Untag the address to avoid spurious faults. Link: https://lkml.kernel.org/r/ebef6425f4468d063e2f09c1b62ccbb2236b71d3.1606161801.git.andreyknvl@google.com Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Alexander Potapenko <glider@google.com> Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Marco Elver <elver@google.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
-rw-r--r--mm/page_alloc.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 139ab8fe5c72..011d4466f33e 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -7656,6 +7656,11 @@ unsigned long free_reserved_area(void *start, void *end, int poison, const char
* alias for the memset().
*/
direct_map_addr = page_address(page);
+ /*
+ * Perform a kasan-unchecked memset() since this memory
+ * has not been initialized.
+ */
+ direct_map_addr = kasan_reset_tag(direct_map_addr);
if ((unsigned int)poison <= 0xFF)
memset(direct_map_addr, poison, PAGE_SIZE);