| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.19 037/116] cgroup1: dont call release_agent when it is "" | Date | Wed, 1 Apr 2020 18:16:53 +0200 |
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From: Tycho Andersen <tycho@tycho.ws>
[ 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@tycho.ws> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- 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 c9628b9a41d23..dd8bdbfbbde1e 100644 --- a/kernel/cgroup/cgroup-v1.c +++ b/kernel/cgroup/cgroup-v1.c @@ -812,7 +812,7 @@ 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
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