6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ben Cressey commit 18d80c77b4c7dd20699e81cedfbbff4e9d198f28 upstream. When integrity_metadata handles a discard, it fills a buffer with DISCARD_FILLER and writes it over the tags, max_blocks blocks at a time. If the kmalloc fails, the buffer is the on-stack array checksums_onstack and max_size is set to HASH_MAX_DIGESTSIZE. So if the tag size is larger than HASH_MAX_DIGESTSIZE, max_blocks is zero, bi_size is never decremented and the loop never terminates. Fix this by using sizeof(checksums_onstack) as max_size. The array has MAX_TAG_SIZE bytes since commit b93b6643e9b5 ("dm integrity: fix a crash with unusually large tag size"), so max_blocks is at least 1. Fixes: 84597a44a9d8 ("dm integrity: add optional discard support") Cc: stable@vger.kernel.org Reviewed-by: Jose Fernandez (Anthropic) Signed-off-by: Ben Cressey Assisted-by: Claude:unspecified Signed-off-by: Mikulas Patocka Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-integrity.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/md/dm-integrity.c +++ b/drivers/md/dm-integrity.c @@ -1979,7 +1979,7 @@ static void integrity_metadata(struct wo if (unlikely(dio->op == REQ_OP_DISCARD)) { unsigned int bi_size = dio->bio_details.bi_iter.bi_size; - unsigned int max_size = likely(checksums != checksums_onstack) ? PAGE_SIZE : HASH_MAX_DIGESTSIZE; + unsigned int max_size = likely(checksums != checksums_onstack) ? PAGE_SIZE : sizeof(checksums_onstack); unsigned int max_blocks = (max_size - extra_space) / ic->tag_size; sector_t sector = dio->range.logical_sector;