diff options
| author | Tao Cui <cuitao@kylinos.cn> | 2026-07-15 21:24:07 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2026-07-15 16:31:43 -0600 |
| commit | dbbca20764382b4d411ec2918f4e278ffe547acc (patch) | |
| tree | 75bf75431aa203c7ec16c213accf0f39c4f5fcdd | |
| parent | c4f4c0fc551cbcdccbbbc2d874d7d6440c7b4983 (diff) | |
blk-cgroup: fix leaks and online flag on radix_tree_insert failure
When radix_tree_insert() fails in blkg_create(), the error path has two
issues:
1. blkg->online is set to true unconditionally, even when the blkg was
never fully inserted. Move the assignment inside the success block.
2. The error path calls blkg_put() without first calling
percpu_ref_kill(). Because the refcount is still in percpu mode,
percpu_ref_put() only does this_cpu_sub() without checking for zero,
so blkg_release() is never triggered. This permanently leaks the
blkg memory, its percpu iostat, policy data, the parent blkg
reference, and the cgroup css reference — the latter preventing the
cgroup from ever being destroyed.
Fix by replacing blkg_put() with percpu_ref_kill(), matching the pattern
used in blkg_destroy().
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Tao Cui <cuitao@kylinos.cn>
Link: https://patch.msgid.link/20260715132407.1469777-1-cui.tao@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | block/blk-cgroup.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index d2a1f5903f24..d9676126c5b5 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -434,15 +434,15 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg, struct gendisk *disk, blkg->pd[i]->online = true; } } + blkg->online = true; } - blkg->online = true; spin_unlock(&blkcg->lock); if (!ret) return blkg; /* @blkg failed fully initialized, use the usual release path */ - blkg_put(blkg); + percpu_ref_kill(&blkg->refcnt); return ERR_PTR(ret); err_free_blkg: |