From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:38236 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752846AbdAFPAr (ORCPT ); Fri, 6 Jan 2017 10:00:47 -0500 Subject: Patch "md/raid5: limit request size according to implementation limits" has been added to the 4.8-stable tree To: khlebnikov@yandex-team.ru, gregkh@linuxfoundation.org, neilb@suse.com, shli@fb.com, shli@kernel.org Cc: , From: Date: Fri, 06 Jan 2017 16:00:29 +0100 Message-ID: <1483714829122250@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: This is a note to let you know that I've just added the patch titled md/raid5: limit request size according to implementation limits to the 4.8-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: md-raid5-limit-request-size-according-to-implementation-limits.patch and it can be found in the queue-4.8 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From e8d7c33232e5fdfa761c3416539bc5b4acd12db5 Mon Sep 17 00:00:00 2001 From: Konstantin Khlebnikov Date: Sun, 27 Nov 2016 19:32:32 +0300 Subject: md/raid5: limit request size according to implementation limits From: Konstantin Khlebnikov commit e8d7c33232e5fdfa761c3416539bc5b4acd12db5 upstream. Current implementation employ 16bit counter of active stripes in lower bits of bio->bi_phys_segments. If request is big enough to overflow this counter bio will be completed and freed too early. Fortunately this not happens in default configuration because several other limits prevent that: stripe_cache_size * nr_disks effectively limits count of active stripes. And small max_sectors_kb at lower disks prevent that during normal read/write operations. Overflow easily happens in discard if it's enabled by module parameter "devices_handle_discard_safely" and stripe_cache_size is set big enough. This patch limits requests size with 256Mb - 8Kb to prevent overflows. Signed-off-by: Konstantin Khlebnikov Cc: Shaohua Li Cc: Neil Brown Signed-off-by: Shaohua Li Signed-off-by: Greg Kroah-Hartman --- drivers/md/raid5.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -7017,6 +7017,15 @@ static int raid5_run(struct mddev *mddev stripe = (stripe | (stripe-1)) + 1; mddev->queue->limits.discard_alignment = stripe; mddev->queue->limits.discard_granularity = stripe; + + /* + * We use 16-bit counter of active stripes in bi_phys_segments + * (minus one for over-loaded initialization) + */ + blk_queue_max_hw_sectors(mddev->queue, 0xfffe * STRIPE_SECTORS); + blk_queue_max_discard_sectors(mddev->queue, + 0xfffe * STRIPE_SECTORS); + /* * unaligned part of discard request will be ignored, so can't * guarantee discard_zeroes_data Patches currently in stable-queue which might be from khlebnikov@yandex-team.ru are queue-4.8/md-raid5-limit-request-size-according-to-implementation-limits.patch