KMSAN doesn't allow treating adjacent memory pages as such, if they were allocated by different alloc_pages() calls. The block layer however does so: adjacent pages end up being used together. To prevent this, make page_is_mergeable() return false under KMSAN. Suggested-by: Eric Biggers <ebiggers@xxxxxxxxxx> Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Eric Biggers <ebiggers@xxxxxxxxxx> Cc: Jens Axboe <axboe@xxxxxxxxx> Cc: Vegard Nossum <vegard.nossum@xxxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Marco Elver <elver@xxxxxxxxxx> Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Cc: linux-mm@xxxxxxxxx --- Change-Id: Iff367f421d51fac549e31ed122365b7539642cff --- block/bio.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/block/bio.c b/block/bio.c index 0985f34225561..09503ef00bc20 100644 --- a/block/bio.c +++ b/block/bio.c @@ -696,6 +696,8 @@ static inline bool page_is_mergeable(const struct bio_vec *bv, *same_page = ((vec_end_addr & PAGE_MASK) == page_addr); if (!*same_page && pfn_to_page(PFN_DOWN(vec_end_addr)) + 1 != page) return false; + if (!*same_page && IS_ENABLED(CONFIG_KMSAN)) + return false; return true; } -- 2.25.1.696.g5e7596f4ac-goog
