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authorLi Zefan <lizf@cn.fujitsu.com>2010-02-02 13:44:10 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2010-02-02 18:11:22 -0800
commit4528fd0595847c2078b59f24800e751c2d6b7e41 (patch)
tree0be4aca79bc9b6709d4762f43ae53e2589931a85
parentef2b9b054580ef835078d8aa411bd06542cd5c1c (diff)
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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 <lizf@cn.fujitsu.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Acked-by: Paul Menage <menage@google.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/cgroup.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 1fbcc748044..aa3bee56644 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. */
}