This is a note to let you know that I've just added the patch titled

    mm: fix page leak at nfs_symlink()

to the 3.12-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:
     mm-fix-page-leak-at-nfs_symlink.patch
and it can be found in the queue-3.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From a0b54adda3fe4b4cc6d28f2a9217cd35d1aa888c Mon Sep 17 00:00:00 2001
From: Rafael Aquini <[email protected]>
Date: Mon, 10 Feb 2014 14:25:48 -0800
Subject: mm: fix page leak at nfs_symlink()

From: Rafael Aquini <[email protected]>

commit a0b54adda3fe4b4cc6d28f2a9217cd35d1aa888c upstream.

Changes in commit a0b8cab3b9b2 ("mm: remove lru parameter from
__pagevec_lru_add and remove parts of pagevec API") have introduced a
call to add_to_page_cache_lru() which causes a leak in nfs_symlink() as
now the page gets an extra refcount that is not dropped.

Jan Stancek observed and reported the leak effect while running test8
from Connectathon Testsuite.  After several iterations over the test
case, which creates several symlinks on a NFS mountpoint, the test
system was quickly getting into an out-of-memory scenario.

This patch fixes the page leak by dropping that extra refcount
add_to_page_cache_lru() is grabbing.

Signed-off-by: Jan Stancek <[email protected]>
Signed-off-by: Rafael Aquini <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Acked-by: Rik van Riel <[email protected]>
Cc: Jeff Layton <[email protected]>
Cc: Trond Myklebust <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 fs/nfs/dir.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1852,6 +1852,11 @@ int nfs_symlink(struct inode *dir, struc
                                                        GFP_KERNEL)) {
                SetPageUptodate(page);
                unlock_page(page);
+               /*
+                * add_to_page_cache_lru() grabs an extra page refcount.
+                * Drop it here to avoid leaking this page later.
+                */
+               page_cache_release(page);
        } else
                __free_page(page);
 


Patches currently in stable-queue which might be from [email protected] are

queue-3.12/mm-fix-page-leak-at-nfs_symlink.patch
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