From: Tycho Andersen <tycho@xxxxxxxx>
[ Upstream commit 2e5383d7904e60529136727e49629a82058a5607 ]
Older (and maybe current) versions of systemd set release_agent to "" when
shutting down, but do not set notify_on_release to 0.
Since 64e90a8acb85 ("Introduce STATIC_USERMODEHELPER to mediate
call_usermodehelper()"), we filter out such calls when the user mode helper
path is "". However, when used in conjunction with an actual (i.e. non "")
STATIC_USERMODEHELPER, the path is never "", so the real usermode helper
will be called with argv[0] == "".
Let's avoid this by not invoking the release_agent when it is "".
Signed-off-by: Tycho Andersen <tycho@xxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
kernel/cgroup/cgroup-v1.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index 2db582706ec5c..f684c82efc2ea 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -784,7 +784,7 @@ void cgroup1_release_agent(struct work_struct *work)
pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
agentbuf = kstrdup(cgrp->root->release_agent_path, GFP_KERNEL);
- if (!pathbuf || !agentbuf)
+ if (!pathbuf || !agentbuf || !strlen(agentbuf))
goto out;
spin_lock_irq(&css_set_lock);
--
2.20.1
