From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:35920 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726721AbeJKXGn (ORCPT ); Thu, 11 Oct 2018 19:06:43 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Xiao Ni , Neil Brown , Shaohua Li , Sasha Levin Subject: [PATCH 3.18 075/120] RAID10 BUG_ON in raise_barrier when force is true and conf->barrier is 0 Date: Thu, 11 Oct 2018 17:34:16 +0200 Message-Id: <20181011152552.905621547@linuxfoundation.org> In-Reply-To: <20181011152549.500488630@linuxfoundation.org> References: <20181011152549.500488630@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiao Ni [ Upstream commit 1d0ffd264204eba1861865560f1f7f7a92919384 ] In raid10 reshape_request it gets max_sectors in read_balance. If the underlayer disks have bad blocks, the max_sectors is less than last. It will call goto read_more many times. It calls raise_barrier(conf, sectors_done != 0) every time. In this condition sectors_done is not 0. So the value passed to the argument force of raise_barrier is true. In raise_barrier it checks conf->barrier when force is true. If force is true and conf->barrier is 0, it panic. In this case reshape_request submits bio to under layer disks. And in the callback function of the bio it calls lower_barrier. If the bio finishes before calling raise_barrier again, it can trigger the BUG_ON. Add one pair of raise_barrier/lower_barrier to fix this bug. Signed-off-by: Xiao Ni Suggested-by: Neil Brown Signed-off-by: Shaohua Li Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/md/raid10.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -4423,11 +4423,12 @@ static sector_t reshape_request(struct m allow_barrier(conf); } + raise_barrier(conf, 0); read_more: /* Now schedule reads for blocks from sector_nr to last */ r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO); r10_bio->state = 0; - raise_barrier(conf, sectors_done != 0); + raise_barrier(conf, 1); atomic_set(&r10_bio->remaining, 0); r10_bio->mddev = mddev; r10_bio->sector = sector_nr; @@ -4532,6 +4533,8 @@ bio_full: if (sector_nr <= last) goto read_more; + lower_barrier(conf); + /* Now that we have done the whole section we can * update reshape_progress */