From 8f121918f2e49f852de1acdc5255cc1ef440d85b Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 29 Mar 2012 22:03:33 -0700 Subject: [PATCH] cgroup: cgroup_attach_task() could return -errno after success 61d1d219c4 "cgroup: remove extra calls to find_existing_css_set" made cgroup_task_migrate() return void. An unfortunate side effect was that cgroup_attach_task() was depending on that function's return value to clear its @retval on the success path. On cgroup mounts without any subsystem with ->can_attach() callback, cgroup_attach_task() ended up returning @retval without initializing it on success. For some reason, gcc failed to warn about it and it didn't cause cgroup_attach_task() to return non-zero value in many cases, probably due to difference in register allocation. When the problem materializes, systemd fails to populate /systemd cgroup mount and fails to boot. Fix it by initializing @retval to zero on declaration. Signed-off-by: Tejun Heo Reported-by: Jiri Kosina LKML-Reference: Reviewed-by: Mandeep Singh Baines Acked-by: Li Zefan --- kernel/cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index f4ea4b6f3cf..ed64ccac67c 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1883,7 +1883,7 @@ static void cgroup_task_migrate(struct cgroup *cgrp, struct cgroup *oldcgrp, */ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk) { - int retval; + int retval = 0; struct cgroup_subsys *ss, *failed_ss = NULL; struct cgroup *oldcgrp; struct cgroupfs_root *root = cgrp->root; -- 2.34.1