From 546e54d4776683c34a1d52ee6ebbbfa7d9aa63c3 Mon Sep 17 00:00:00 2001 From: Francesco Ruggeri Date: Thu, 13 Sep 2012 15:03:37 -0700 Subject: [PATCH] fs/proc: fix potential unregister_sysctl_table hang commit 6bf6104573482570f7103d3e5ddf9574db43a363 upstream. 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 076c3eed2c31 ("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: Francesco Ruggeri Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/proc/proc_sysctl.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 3476bca8f7af9..5d00eb82df8b7 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -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; } -- 2.47.2