The patch titled cgroup: catch bad css refcnt at css_put has been removed from the -mm tree. Its filename was cgroup-catch-bad-css-refcnt-at-css_put.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: cgroup: catch bad css refcnt at css_put From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> __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@xxxxxxxxxxxxxx> Cc: Paul Menage <menage@xxxxxxxxxx> Cc: Li Zefan <lizf@xxxxxxxxxxxxxx> Cc: Balbir Singh <balbir@xxxxxxxxxx> Cc: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/cgroup.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff -puN kernel/cgroup.c~cgroup-catch-bad-css-refcnt-at-css_put kernel/cgroup.c --- a/kernel/cgroup.c~cgroup-catch-bad-css-refcnt-at-css_put +++ a/kernel/cgroup.c @@ -3708,8 +3708,10 @@ static void check_for_release(struct cgr 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_stat cgroup_wakeup_rmdir_waiter(cgrp); } rcu_read_unlock(); + WARN_ON_ONCE(val < 1); } /* _ Patches currently in -mm which might be from kamezawa.hiroyu@xxxxxxxxxxxxxx are -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html