3.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: Francesco Ruggeri <frugg...@aristanetworks.com>
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 <frugg...@aristanetworks.com>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
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 dfafeb2..eb7cc91 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;
}
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