From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from wout2-smtp.messagingengine.com ([64.147.123.25]:59545 "EHLO wout2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725901AbeLCKFB (ORCPT ); Mon, 3 Dec 2018 05:05:01 -0500 Subject: FAILED: patch "[PATCH] btrfs: relocation: set trans to be NULL after ending" failed to apply to 4.9-stable tree To: bianpan2016@163.com, dsterba@suse.com, wqu@suse.com Cc: From: Date: Mon, 03 Dec 2018 11:04:36 +0100 Message-ID: <154383147661119@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >>From 42a657f57628402c73237547f0134e083e2f6764 Mon Sep 17 00:00:00 2001 From: Pan Bian Date: Fri, 23 Nov 2018 18:10:15 +0800 Subject: [PATCH] btrfs: relocation: set trans to be NULL after ending transaction The function relocate_block_group calls btrfs_end_transaction to release trans when update_backref_cache returns 1, and then continues the loop body. If btrfs_block_rsv_refill fails this time, it will jump out the loop and the freed trans will be accessed. This may result in a use-after-free bug. The patch assigns NULL to trans after trans is released so that it will not be accessed. Fixes: 0647bf564f1 ("Btrfs: improve forever loop when doing balance relocation") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Qu Wenruo Signed-off-by: Pan Bian Reviewed-by: David Sterba Signed-off-by: David Sterba diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 924116f654a1..a3f75b8926d4 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -3959,6 +3959,7 @@ static noinline_for_stack int relocate_block_group(struct reloc_control *rc) restart: if (update_backref_cache(trans, &rc->backref_cache)) { btrfs_end_transaction(trans); + trans = NULL; continue; }