Patch "afs: Fix page leak in afs_write_begin()" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

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

    afs: Fix page leak in afs_write_begin()

to the 4.4-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:
     afs-fix-page-leak-in-afs_write_begin.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Mon Dec 18 14:47:43 CET 2017
From: David Howells <dhowells@redhat.com>
Date: Thu, 16 Mar 2017 16:27:48 +0000
Subject: afs: Fix page leak in afs_write_begin()

From: David Howells <dhowells@redhat.com>


[ Upstream commit 6d06b0d25209c80e99c1e89700f1e09694a3766b ]

afs_write_begin() leaks a ref and a lock on a page if afs_fill_page()
fails.  Fix the leak by unlocking and releasing the page in the error path.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/afs/write.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -148,12 +148,12 @@ int afs_write_begin(struct file *file, s
 		kfree(candidate);
 		return -ENOMEM;
 	}
-	*pagep = page;
-	/* page won't leak in error case: it eventually gets cleaned off LRU */
 
 	if (!PageUptodate(page) && len != PAGE_CACHE_SIZE) {
 		ret = afs_fill_page(vnode, key, index << PAGE_CACHE_SHIFT, page);
 		if (ret < 0) {
+			unlock_page(page);
+			put_page(page);
 			kfree(candidate);
 			_leave(" = %d [prep]", ret);
 			return ret;
@@ -161,6 +161,9 @@ int afs_write_begin(struct file *file, s
 		SetPageUptodate(page);
 	}
 
+	/* page won't leak in error case: it eventually gets cleaned off LRU */
+	*pagep = page;
+
 try_again:
 	spin_lock(&vnode->writeback_lock);
 


Patches currently in stable-queue which might be from dhowells@redhat.com are

queue-4.4/afs-flush-outstanding-writes-when-an-fd-is-closed.patch
queue-4.4/afs-fix-the-maths-in-afs_fs_store_data.patch
queue-4.4/afs-populate-group-id-from-vnode-status.patch
queue-4.4/afs-prevent-callback-expiry-timer-overflow.patch
queue-4.4/keys-add-missing-permission-check-for-request_key-destination.patch
queue-4.4/afs-adjust-mode-bits-processing.patch
queue-4.4/afs-fix-page-leak-in-afs_write_begin.patch
queue-4.4/afs-fix-missing-put_page.patch
queue-4.4/afs-migrate-vlocation-fields-to-64-bit.patch
queue-4.4/afs-populate-and-use-client-modification-time.patch
queue-4.4/afs-fix-afs_kill_pages.patch