Commit 6bf61045 authored by Francesco Ruggeri's avatar Francesco Ruggeri Committed by Linus Torvalds

fs/proc: fix potential unregister_sysctl_table hang

The unregister_sysctl_table() function hangs if all references to its
ctl_table_header structure are not dropped.

This can happen sometimes because of a leak in proc_sys_lookup():
proc_sys_lookup() gets a reference to the table via lookup_entry(), but
it does not release it when a subsequent call to sysctl_follow_link()
fails.

This patch fixes this leak by making sure the reference is always
dropped on return.

See also commit 076c3eed ("sysctl: Rewrite proc_sys_lookup
introducing find_entry and lookup_entry") which reorganized this code in
3.4.

Tested in Linux 3.4.4.
Signed-off-by: default avatarFrancesco Ruggeri <fruggeri@aristanetworks.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5698bd75
......@@ -462,9 +462,6 @@ static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
err = ERR_PTR(-ENOMEM);
inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
if (h)
sysctl_head_finish(h);
if (!inode)
goto out;
......@@ -473,6 +470,8 @@ static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
d_add(dentry, inode);
out:
if (h)
sysctl_head_finish(h);
sysctl_head_finish(head);
return err;
}
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment