cgroup: fix the retry path of cgroup_mount()
If we hit the retry path, we'll call parse_cgroupfs_options() again,
but the string we pass to it has been modified by the previous call
to this function.
This bug can be observed by:
# mount -t cgroup -o name=foo,cpuset xxx /mnt && umount /mnt && \
mount -t cgroup -o name=foo,cpuset xxx /mnt
mount: wrong fs type, bad option, bad superblock on xxx,
missing codepage or helper program, or other error
...
The second mount passed "name=foo,cpuset" to the parser, and then it
hit the retry path and call the parser again, but this time the string
passed to the parser is "name=foo".
To fix this, we avoid calling parse_cgroupfs_options() again in this
case.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 9fcdaa7..11a03d6 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1495,7 +1495,7 @@
*/
if (!use_task_css_set_links)
cgroup_enable_task_cg_lists();
-retry:
+
mutex_lock(&cgroup_tree_mutex);
mutex_lock(&cgroup_mutex);
@@ -1503,7 +1503,7 @@
ret = parse_cgroupfs_options(data, &opts);
if (ret)
goto out_unlock;
-
+retry:
/* look for a matching existing root */
if (!opts.subsys_mask && !opts.none && !opts.name) {
cgrp_dfl_root_visible = true;
@@ -1562,9 +1562,9 @@
if (!atomic_inc_not_zero(&root->cgrp.refcnt)) {
mutex_unlock(&cgroup_mutex);
mutex_unlock(&cgroup_tree_mutex);
- kfree(opts.release_agent);
- kfree(opts.name);
msleep(10);
+ mutex_lock(&cgroup_tree_mutex);
+ mutex_lock(&cgroup_mutex);
goto retry;
}
