This is a note to let you know that I've just added the patch titled
fs/proc: fix potential unregister_sysctl_table hang
to the 3.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fs-proc-fix-potential-unregister_sysctl_table-hang.patch
and it can be found in the queue-3.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 6bf6104573482570f7103d3e5ddf9574db43a363 Mon Sep 17 00:00:00 2001
From: Francesco Ruggeri <[email protected]>
Date: Thu, 13 Sep 2012 15:03:37 -0700
Subject: fs/proc: fix potential unregister_sysctl_table hang
From: Francesco Ruggeri <[email protected]>
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 <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/proc/proc_sysctl.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -113,9 +113,6 @@ static struct dentry *proc_sys_lookup(st
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;
@@ -124,6 +121,8 @@ static struct dentry *proc_sys_lookup(st
d_add(dentry, inode);
out:
+ if (h)
+ sysctl_head_finish(h);
sysctl_head_finish(head);
return err;
}
Patches currently in stable-queue which might be from
[email protected] are
queue-3.0/fs-proc-fix-potential-unregister_sysctl_table-hang.patch
queue-3.0/net-ipv4-ipmr_expire_timer-causes-crash-when-removing-net-namespace.patch
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