ms commit b7d6c3033323 ("block: fix use-after-free on cached
last_lookup partition") has changed the semantic of
disk_map_sector_rcu() function: previously it only returned appropriate
partition but after the patch it additionally gets a refcounter on that
partition.RedHat has backported that patch in RHEL7 as https://access.redhat.com/labs/rhcb/RHEL-7.9/kernel-3.10.0-1160.31.1.el7/patches/blob/1050-block-fix-use-after-free-on-cached-last_lookup-parti.patch We use disk_map_sector_rcu() in ploop_make_request() for getting proper partition for correct i/o accounting and thus during the rebase of 3.10.0-1160.25.1.vz7.180.12 onto 3.10.0-1160.31.1.el7 (3.10.0-1160.31.1.vz7.181.1) we've got refcounters leak which led to: * leaking hd_struct-s for ploop devices partitions on Containers start/stop, suspend/resume, mount/umount, etc. * as a side effect we've got broken statistics for ploop partitions in 50% cases (always zeroes are shown) Fix the leak by adding pair hd_struct_put() into ploop code. Fixes: 03edeead80d9 ("ploop: fix gendisk disk_stats to be seen on partition") https://jira.sw.ru/browse/PSBM-131919 Signed-off-by: Konstantin Khorenko <khore...@virtuozzo.com> --- block/partition-generic.c | 1 + drivers/block/ploop/dev.c | 1 + 2 files changed, 2 insertions(+) diff --git a/block/partition-generic.c b/block/partition-generic.c index 164d364fb793..dd3a185f8683 100644 --- a/block/partition-generic.c +++ b/block/partition-generic.c @@ -253,6 +253,7 @@ void __delete_partition(struct hd_struct *part) call_rcu(&part->rcu_head, delete_partition_rcu_cb); } +EXPORT_SYMBOL(__delete_partition); void delete_partition(struct gendisk *disk, int partno) { diff --git a/drivers/block/ploop/dev.c b/drivers/block/ploop/dev.c index 9abce6afa976..06b72542633b 100644 --- a/drivers/block/ploop/dev.c +++ b/drivers/block/ploop/dev.c @@ -982,6 +982,7 @@ static void ploop_make_request(struct request_queue *q, struct bio *bio) part = disk_map_sector_rcu(plo->disk, bio->bi_sector); part_stat_inc(cpu, part, ios[rw]); part_stat_add(cpu, part, sectors[rw], bio_sectors(bio)); + hd_struct_put(part); part_stat_unlock(); if (blk_queue_standby(plo->queue)) { -- 2.24.3 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
