From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:52476 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S939126AbdAFVux (ORCPT ); Fri, 6 Jan 2017 16:50:53 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Konstantin Khlebnikov , Shaohua Li , Neil Brown , Shaohua Li Subject: [PATCH 4.8 55/96] md/raid5: limit request size according to implementation limits Date: Fri, 6 Jan 2017 22:43:43 +0100 Message-Id: <20170106214229.943780204@linuxfoundation.org> In-Reply-To: <20170106214227.601120243@linuxfoundation.org> References: <20170106214227.601120243@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.8-stable review patch. If anyone has any objections, please let me know. ------------------ 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