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 <tj@xxxxxxxxxx>
Reported-by: Jiri Kosina <jkosina@xxxxxxx>
LKML-Reference: <alpine.LNX.2.00.1203282354440.25526@xxxxxxxxxxxxx>
---
Jiri, can you please confirm the fix?
Thanks.
kernel/cgroup.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index f4ea4b6..ed64cca 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;
--
To unsubscribe from this list: send the line "unsubscribe cgroups" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
