KMSAN metadata for consequent physical pages may be inconsequent, therefore accessing such pages together may lead to metadata corruption. We disable merging pages in biovec to prevent such corruptions. Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx> To: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Jens Axboe <axboe@xxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Vegard Nossum <vegard.nossum@xxxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Marco Elver <elver@xxxxxxxxxx> Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: linux-mm@xxxxxxxxx --- v4: - use IS_ENABLED instead of #ifdef (as requested by Marco Elver) Change-Id: Id2f2babaf662ac44675c4f2790f4a80ddc328fa7 --- block/blk.h | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/block/blk.h b/block/blk.h index 670337b7cfa0d..065dfee244118 100644 --- a/block/blk.h +++ b/block/blk.h @@ -79,6 +79,13 @@ static inline bool biovec_phys_mergeable(struct request_queue *q, phys_addr_t addr1 = page_to_phys(vec1->bv_page) + vec1->bv_offset; phys_addr_t addr2 = page_to_phys(vec2->bv_page) + vec2->bv_offset; + /* + * Merging consequent physical pages may not work correctly under KMSAN + * if their metadata pages aren't consequent. Just disable merging. + */ + if (IS_ENABLED(CONFIG_KMSAN)) + return false; + if (addr1 + vec1->bv_len != addr2) return false; if (xen_domain() && !xen_biovec_phys_mergeable(vec1, vec2->bv_page)) -- 2.25.1.696.g5e7596f4ac-goog
