[Devel] [PATCH RHEL7] cgroup: fixed NULL-pointer dereference in cgroup_release_agent

[Valeriy Vdovin]

The fix checks that ve->init_task is not referenced during warning
message decision if ve == ve0, because ve0 init_task is always NULL.

https://jira.sw.ru/browse/PSBM-107673
Signed-off-by: Valeriy Vdovin <valeriy.vdovin at virtuozzo.com>
---
 kernel/cgroup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 691505c..27d7a5e 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -5934,7 +5934,7 @@ void cgroup_release_agent(struct work_struct *work)
 			envp, UMH_WAIT_EXEC, NULL, NULL, NULL);
 
 		ve_task = ve->init_task;
-		if (err < 0 && (!(ve_task->flags & PF_EXITING)))
+		if (err < 0 && (ve == &ve0 || !(ve_task->flags & PF_EXITING)))
 			pr_warn_ratelimited("cgroup release_agent "
 					    "%s %s failed: %d\n",
 					    agentbuf, pathbuf, err);
-- 
1.8.3.1