Messages in this thread | | | Date | Thu, 22 Apr 2010 12:57:25 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH 5/5] blk-cgroup: Fix an RCU warning in blkiocg_create() |
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On Thu, Apr 22, 2010 at 05:32:28PM +0800, Li Zefan wrote: > 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.
Queued for 2.6.34, thank you!
Thanx, Paul
> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> > --- > 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 5fe03de..2cc682b 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); > -- > 1.6.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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