From 4528fd0595847c2078b59f24800e751c2d6b7e41 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Tue, 2 Feb 2010 13:44:10 -0800 Subject: [PATCH] cgroups: fix to return errno in a failure path In cgroup_create(), if alloc_css_id() returns failure, the errno is not propagated to userspace, so mkdir will fail silently. To trigger this bug, we mount blkio (or memory subsystem), and create more then 65534 cgroups. (The number of cgroups is limited to 65535 if a subsystem has use_id == 1) # mount -t cgroup -o blkio xxx /mnt # for ((i = 0; i < 65534; i++)); do mkdir /mnt/$i; done # mkdir /mnt/65534 (should return ENOSPC) # Signed-off-by: Li Zefan Acked-by: Serge Hallyn Acked-by: Paul Menage Acked-by: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/cgroup.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 1fbcc748044a..aa3bee566446 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2936,14 +2936,17 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, for_each_subsys(root, ss) { struct cgroup_subsys_state *css = ss->create(ss, cgrp); + if (IS_ERR(css)) { err = PTR_ERR(css); goto err_destroy; } init_cgroup_css(css, ss, cgrp); - if (ss->use_id) - if (alloc_css_id(ss, parent, cgrp)) + if (ss->use_id) { + err = alloc_css_id(ss, parent, cgrp); + if (err) goto err_destroy; + } /* At error, ->destroy() callback has to free assigned ID. */ } -- 2.30.2