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authorFrancesco Ruggeri <fruggeri@aristanetworks.com>2012-09-13 15:03:37 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-09-17 10:32:03 -0700
commit6bf6104573482570f7103d3e5ddf9574db43a363 (patch)
tree4aa02983bfffbe0d623c0163822354b48693eca0
parent5698bd757d55b1bb87edd1a9744ab09c142abfc2 (diff)
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 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 <fruggeri@aristanetworks.com> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/proc/proc_sysctl.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index dfafeb2b05a..eb7cc91b725 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;
}