It looks like the c6b3d5bcd67c ("cgroup: fix top cgroup refcnt leak")
commit was reverted by mistake.
$ mkdir /tmp/cgroup
$ mkdir /tmp/cgroup2
$ mount -t cgroup -o none,name=test test /tmp/cgroup
$ mount -t cgroup -o none,name=test test /tmp/cgroup2
$ umount /tmp/cgroup
$ umount /tmp/cgroup2
$ cat /proc/self/cgroup | grep test
12:name=test:/
You can see the test cgroup was not freed.
Cc: Li Zefan <lizefan@xxxxxxxxxx>
Fixes: aea3f2676c83 ("kernfs, sysfs, cgroup, intel_rdt: Support fs_context")
Signed-off-by: Andrei Vagin <avagin@xxxxxxxxx>
---
v2: clean up code and add the vfs/for-next tag
v3: fix a reference leak when kernfs_node_dentry fails
kernel/cgroup/cgroup.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index fb0717696895..b43479d1f9a3 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -2019,7 +2019,7 @@ int cgroup_do_get_tree(struct fs_context *fc)
ret = kernfs_get_tree(fc);
if (ret < 0)
- goto out_cgrp;
+ return ret;
/*
* In non-init cgroup namespace, instead of root cgroup's dentry,
@@ -2038,19 +2038,22 @@ int cgroup_do_get_tree(struct fs_context *fc)
mutex_unlock(&cgroup_mutex);
nsdentry = kernfs_node_dentry(cgrp->kn, fc->root->d_sb);
- if (IS_ERR(nsdentry))
- return PTR_ERR(nsdentry);
+ if (IS_ERR(nsdentry)) {
+ ret = PTR_ERR(nsdentry);
+ goto out_cgrp;
+ }
dput(fc->root);
fc->root = nsdentry;
}
ret = 0;
- if (ctx->kfc.new_sb_created)
- goto out_cgrp;
- apply_cgroup_root_flags(ctx->flags);
- return 0;
+ if (!ctx->kfc.new_sb_created)
+ apply_cgroup_root_flags(ctx->flags);
out_cgrp:
+ if (!ctx->kfc.new_sb_created)
+ cgroup_put(&ctx->root->cgrp);
+
return ret;
}
--
2.17.2
