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authorJan Kara <jack@suse.cz>2022-04-01 13:27:45 +0300
committerJens Axboe <axboe@kernel.dk>2022-04-18 04:34:20 +0300
commitea591cd4eb270393810e7be01feb8fde6a34fbbe (patch)
treec6a54e9ebc04cc05ca5652e7e1564224425a74a6
parent3bc5e683c67d94bd839a1da2e796c15847b51b69 (diff)
downloadlinux-ea591cd4eb270393810e7be01feb8fde6a34fbbe.tar.xz
bfq: Update cgroup information before merging bio
When the process is migrated to a different cgroup (or in case of writeback just starts submitting bios associated with a different cgroup) bfq_merge_bio() can operate with stale cgroup information in bic. Thus the bio can be merged to a request from a different cgroup or it can result in merging of bfqqs for different cgroups or bfqqs of already dead cgroups and causing possible use-after-free issues. Fix the problem by updating cgroup information in bfq_merge_bio(). CC: stable@vger.kernel.org Fixes: e21b7a0b9887 ("block, bfq: add full hierarchical scheduling and cgroups support") Tested-by: "yukuai (C)" <yukuai3@huawei.com> Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20220401102752.8599-4-jack@suse.cz Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--block/bfq-iosched.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 89fe3f85eb3c..1fc4d4628fba 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -2457,10 +2457,17 @@ static bool bfq_bio_merge(struct request_queue *q, struct bio *bio,
spin_lock_irq(&bfqd->lock);
- if (bic)
+ if (bic) {
+ /*
+ * Make sure cgroup info is uptodate for current process before
+ * considering the merge.
+ */
+ bfq_bic_update_cgroup(bic, bio);
+
bfqd->bio_bfqq = bic_to_bfqq(bic, op_is_sync(bio->bi_opf));
- else
+ } else {
bfqd->bio_bfqq = NULL;
+ }
bfqd->bio_bic = bic;
ret = blk_mq_sched_try_merge(q, bio, nr_segs, &free);