diff options
| author | Yu Kuai <yukuai3@huawei.com> | 2025-09-23 15:01:01 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-09-23 01:35:52 -0600 |
| commit | 670bfe683850cb29957a9d71f997e9774eb24de6 (patch) | |
| tree | 09ea5172b2f505a5e2eae44e1e8c2e2b7c19bdfa | |
| parent | fea55691aca1edf2fe612fd75536ec26354a8c4a (diff) | |
blk-mq: fix null-ptr-deref in blk_mq_free_tags() from error path
blk_mq_free_tags() can be called after blk_mq_init_tags(), while
tags->page_list is still not initialized, causing null-ptr-deref.
Fix this problem by initializing tags->page_list at blk_mq_init_tags(),
meanwhile, also free tags directly from error path because there is no
srcu barrier.
Fixes: ad0d05dbddc1 ("blk-mq: Defer freeing of tags page_list to SRCU callback")
Reported-by: syzbot+5c5d41e80248d610221f@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/68d1b079.a70a0220.1b52b.0000.GAE@google.com/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | block/blk-mq-tag.c | 9 | ||||
| -rw-r--r-- | block/blk-mq.c | 2 |
2 files changed, 9 insertions, 2 deletions
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index 271fa005c51e..c7a4d4b9cc87 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -566,6 +566,8 @@ struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags, tags->nr_tags = total_tags; tags->nr_reserved_tags = reserved_tags; spin_lock_init(&tags->lock); + INIT_LIST_HEAD(&tags->page_list); + if (bt_alloc(&tags->bitmap_tags, depth, round_robin, node)) goto out_free_tags; if (bt_alloc(&tags->breserved_tags, reserved_tags, round_robin, node)) @@ -603,6 +605,13 @@ void blk_mq_free_tags(struct blk_mq_tag_set *set, struct blk_mq_tags *tags) { sbitmap_queue_free(&tags->bitmap_tags); sbitmap_queue_free(&tags->breserved_tags); + + /* if tags pages is not allocated yet, free tags directly */ + if (list_empty(&tags->page_list)) { + kfree(tags); + return; + } + call_srcu(&set->tags_srcu, &tags->rcu_head, blk_mq_free_tags_callback); } diff --git a/block/blk-mq.c b/block/blk-mq.c index 4ccf11cadf8c..09f579414161 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -3582,8 +3582,6 @@ static int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, if (node == NUMA_NO_NODE) node = set->numa_node; - INIT_LIST_HEAD(&tags->page_list); - /* * rq_size is the size of the request plus driver payload, rounded * to the cacheline size |