diff mbox series

[v4,28/45] kmsan: disable physical page merging in biovec

Message ID 20220701142310.2188015-29-glider@google.com (mailing list archive)
State New
Headers show
Series Add KernelMemorySanitizer infrastructure | expand

Commit Message

Alexander Potapenko July 1, 2022, 2:22 p.m. UTC 
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 mbox series

Patch

diff --git a/block/blk.h b/block/blk.h
index 434017701403f..96309a98a60e3 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -93,6 +93,13 @@  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))