From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:40036 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933881AbeCJAWa (ORCPT ); Fri, 9 Mar 2018 19:22:30 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zhang Yi , Mike Snitzer Subject: [PATCH 4.9 25/65] dm io: fix duplicate bio completion due to missing ref count Date: Fri, 9 Mar 2018 16:18:25 -0800 Message-Id: <20180310001826.924856436@linuxfoundation.org> In-Reply-To: <20180310001824.927996722@linuxfoundation.org> References: <20180310001824.927996722@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mike Snitzer commit feb7695fe9fb83084aa29de0094774f4c9d4c9fc upstream. If only a subset of the devices associated with multiple regions support a given special operation (eg. DISCARD) then the dec_count() that is used to set error for the region must increment the io->count. Otherwise, when the dec_count() is called it can cause the dm-io caller's bio to be completed multiple times. As was reported against the dm-mirror target that had mirror legs with a mix of discard capabilities. Bug: https://bugzilla.kernel.org/show_bug.cgi?id=196077 Reported-by: Zhang Yi Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-io.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/md/dm-io.c +++ b/drivers/md/dm-io.c @@ -302,6 +302,7 @@ static void do_region(int op, int op_fla special_cmd_max_sectors = q->limits.max_write_same_sectors; if ((op == REQ_OP_DISCARD || op == REQ_OP_WRITE_SAME) && special_cmd_max_sectors == 0) { + atomic_inc(&io->count); dec_count(io, region, -EOPNOTSUPP); return; }