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| author | Li Zefan <lizf@cn.fujitsu.com> | 2010-05-07 08:57:00 +0200 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2010-05-07 08:57:00 +0200 |
| commit | 0341509fdfc9519f7de6aabc5dd23217cef72b73 (patch) | |
| tree | 84415f35129013b9d8fb3f5f0ef266437a02f09c /block | |
| parent | dcf097b247affd8b88ad410a92298590c5600f44 (diff) | |
| download | lwn-0341509fdfc9519f7de6aabc5dd23217cef72b73.tar.gz lwn-0341509fdfc9519f7de6aabc5dd23217cef72b73.zip | |
blk-cgroup: Fix an RCU warning in blkiocg_create()
with CONFIG_PROVE_RCU=y, a warning can be triggered:
# mount -t cgroup -o blkio xxx /mnt
# mkdir /mnt/subgroup
...
kernel/cgroup.c:4442 invoked rcu_dereference_check() without protection!
...
To fix this, we avoid caling css_depth() here, which is a bit simpler
than the original code.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-cgroup.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 5fe03def34b2..2cc682b860ea 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -286,16 +286,16 @@ done: static struct cgroup_subsys_state * blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup) { - struct blkio_cgroup *blkcg, *parent_blkcg; + struct blkio_cgroup *blkcg; + struct cgroup *parent = cgroup->parent; - if (!cgroup->parent) { + if (!parent) { blkcg = &blkio_root_cgroup; goto done; } /* Currently we do not support hierarchy deeper than two level (0,1) */ - parent_blkcg = cgroup_to_blkio_cgroup(cgroup->parent); - if (css_depth(&parent_blkcg->css) > 0) + if (parent != cgroup->top_cgroup) return ERR_PTR(-EINVAL); blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL); |