diff options
| author | KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> | 2009-10-01 15:44:09 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-10-01 16:11:12 -0700 |
| commit | 3dece8347df6a16239fab10dadb370854f1c969c (patch) | |
| tree | 23a93cdb0dfacd4b89b42c192a6247be84d105bf /kernel/cgroup.c | |
| parent | 26251eaf98e26dc2ce2dc26d63bc502700760704 (diff) | |
| download | lwn-3dece8347df6a16239fab10dadb370854f1c969c.tar.gz lwn-3dece8347df6a16239fab10dadb370854f1c969c.zip | |
cgroup: catch bad css refcnt at css_put
__css_put() doesn't check a bug as refcnt goes to minus.
I think it should be caught. This patch adds a check for it.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index d2b88596efde..ca83b73fba19 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -3708,8 +3708,10 @@ static void check_for_release(struct cgroup *cgrp) void __css_put(struct cgroup_subsys_state *css) { struct cgroup *cgrp = css->cgroup; + int val; rcu_read_lock(); - if (atomic_dec_return(&css->refcnt) == 1) { + val = atomic_dec_return(&css->refcnt); + if (val == 1) { if (notify_on_release(cgrp)) { set_bit(CGRP_RELEASABLE, &cgrp->flags); check_for_release(cgrp); @@ -3717,6 +3719,7 @@ void __css_put(struct cgroup_subsys_state *css) cgroup_wakeup_rmdir_waiter(cgrp); } rcu_read_unlock(); + WARN_ON_ONCE(val < 1); } /* |