[PATCH v7 27/43] kmsan: disable physical page merging in biovec
From: Alexander Potapenko <glider@google.com>
Date: 2022-09-15 15:10:03
Also in:
linux-mm, lkml
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
KMSAN metadata for adjacent physical pages may not be adjacent, 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@google.com> --- Link: https://linux-review.googlesource.com/id/Iece16041be5ee47904fbc98121b105e5be5fea5c --- block/blk.h | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/block/blk.h b/block/blk.h
index d7142c4d2fefb..af02b93c1dba5 100644
--- a/block/blk.h
+++ b/block/blk.h@@ -88,6 +88,13 @@ 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 adjacent physical pages may not work correctly under KMSAN + * if their metadata pages aren't adjacent. 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))
--
2.37.2.789.g6183377224-goog