[3.5.y.z extended stable] Patch "devpts: plug the memory leak in kill_sb" has been added to staging queue

Luis Henriques luis.henriques at canonical.com
Tue Nov 19 13:18:28 UTC 2013


This is a note to let you know that I have just added a patch titled

    devpts: plug the memory leak in kill_sb

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 61cb151bd1b5013ec3bd027910c2b88bc7767f86 Mon Sep 17 00:00:00 2001
From: Ilija Hadzic <ihadzic at research.bell-labs.com>
Date: Tue, 12 Nov 2013 15:11:45 -0800
Subject: devpts: plug the memory leak in kill_sb

commit 66da0e1f9034140ae2f571ef96e254a25083906c upstream.

When devpts is unmounted, there may be a no-longer-used IDR tree hanging
off the superblock we are about to kill.  This needs to be cleaned up
before destroying the SB.

The leak is usually not a big deal because unmounting devpts is typically
done when shutting down the whole machine.  However, shutting down an LXC
container instead of a physical machine exposes the problem (the garbage
is detectable with kmemleak).

Signed-off-by: Ilija Hadzic <ihadzic at research.bell-labs.com>
Cc: Sukadev Bhattiprolu <sukadev at linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/devpts/inode.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index 979c1e3..1ed9d5e 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -483,6 +483,7 @@ static void devpts_kill_sb(struct super_block *sb)
 {
 	struct pts_fs_info *fsi = DEVPTS_SB(sb);

+	ida_destroy(&fsi->allocated_ptys);
 	kfree(fsi);
 	kill_litter_super(sb);
 }
--
1.8.3.2





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