From: Zheng Liang
mainline inclusion
from mainline
commit 2fc428f6b7ca80794cb9928c90d4de524366659f
category: bugfix
issue: #I4NRS5
CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
Signed-off-by: Yu Changchun
-------------------------------------------------
In bfq_pd_alloc(), the function bfqg_stats_init() init bfqg. If
blkg_rwstat_init() init bfqg_stats->bytes successful and init
bfqg_stats->ios failed, bfqg_stats_init() return failed, bfqg will
be freed. But blkg_rwstat->cpu_cnt is not deleted from the list of
percpu_counters. If we traverse the list of percpu_counters, It will
have UAF problem.
we should use blkg_rwstat_exit() to cleanup bfqg_stats bytes in the
above scenario.
Fixes: commit fd41e60331b ("bfq-iosched: stop using blkg->stat_bytes and ->stat_ios")
Signed-off-by: Zheng Liang
Acked-by: Tejun Heo
Link: https://lore.kernel.org/r/20211018024225.1493938-1-zhengliang6@huawei.com
Signed-off-by: Jens Axboe
Reviewed-by: Jason Yan
Signed-off-by: Chen Jun
Signed-off-by: Zheng Zengkai
Signed-off-by: Yu Changchun
---
block/bfq-cgroup.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
index b791e2041e49..a6bcc779c912 100644
--- a/block/bfq-cgroup.c
+++ b/block/bfq-cgroup.c
@@ -463,7 +463,7 @@ static int bfqg_stats_init(struct bfqg_stats *stats, gfp_t gfp)
{
if (blkg_rwstat_init(&stats->bytes, gfp) ||
blkg_rwstat_init(&stats->ios, gfp))
- return -ENOMEM;
+ goto error;
#ifdef CONFIG_BFQ_CGROUP_DEBUG
if (blkg_rwstat_init(&stats->merged, gfp) ||
@@ -476,13 +476,15 @@ static int bfqg_stats_init(struct bfqg_stats *stats, gfp_t gfp)
bfq_stat_init(&stats->dequeue, gfp) ||
bfq_stat_init(&stats->group_wait_time, gfp) ||
bfq_stat_init(&stats->idle_time, gfp) ||
- bfq_stat_init(&stats->empty_time, gfp)) {
- bfqg_stats_exit(stats);
- return -ENOMEM;
- }
+ bfq_stat_init(&stats->empty_time, gfp))
+ goto error;
#endif
return 0;
+
+error:
+ bfqg_stats_exit(stats);
+ return -ENOMEM;
}
static struct bfq_group_data *cpd_to_bfqgd(struct blkcg_policy_data *cpd)
--
2.25.1
