[PATCH 3.10 024/173] devpts: plug the memory leak in kill_sb

Greg Kroah-Hartman
2013-12-02T19:10:07Z

From: Ilija Hadzic <ihadzic@research.bell-labs.com>

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@research.bell-labs.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/devpts/inode.c | 1 +
1 file changed, 1 insertion(+)

--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -498,6 +498,7 @@ static void devpts_kill_sb(struct super_
{
struct pts_fs_info *fsi = DEVPTS_SB(sb);

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