From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:41122 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751613AbbJRAmw (ORCPT ); Sat, 17 Oct 2015 20:42:52 -0400 Subject: Patch "blk-mq: avoid setting hctx->tags->cpumask before allocation" has been added to the 4.2-stable tree To: akinobu.mita@gmail.com, axboe@fb.com, gregkh@linuxfoundation.org, hch@lst.de, keith.busch@intel.com, tom.leiming@gmail.com Cc: , From: Date: Sat, 17 Oct 2015 17:42:51 -0700 Message-ID: <144512897118131@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 blk-mq: avoid setting hctx->tags->cpumask before allocation to the 4.2-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: blk-mq-avoid-setting-hctx-tags-cpumask-before-allocation.patch and it can be found in the queue-4.2 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 1356aae08338f1c19ce1c67bf8c543a267688fc3 Mon Sep 17 00:00:00 2001 From: Akinobu Mita Date: Sun, 27 Sep 2015 02:09:19 +0900 Subject: blk-mq: avoid setting hctx->tags->cpumask before allocation From: Akinobu Mita commit 1356aae08338f1c19ce1c67bf8c543a267688fc3 upstream. When unmapped hw queue is remapped after CPU topology is changed, hctx->tags->cpumask has to be set after hctx->tags is setup in blk_mq_map_swqueue(), otherwise it causes null pointer dereference. Fixes: f26cdc8536 ("blk-mq: Shared tag enhancements") Signed-off-by: Akinobu Mita Cc: Keith Busch Cc: Ming Lei Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- block/blk-mq.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1807,7 +1807,6 @@ static void blk_mq_map_swqueue(struct re hctx = q->mq_ops->map_queue(q, i); cpumask_set_cpu(i, hctx->cpumask); - cpumask_set_cpu(i, hctx->tags->cpumask); ctx->index_hw = hctx->nr_ctx; hctx->ctxs[hctx->nr_ctx++] = ctx; } @@ -1847,6 +1846,14 @@ static void blk_mq_map_swqueue(struct re hctx->next_cpu = cpumask_first(hctx->cpumask); hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; } + + queue_for_each_ctx(q, ctx, i) { + if (!cpu_online(i)) + continue; + + hctx = q->mq_ops->map_queue(q, i); + cpumask_set_cpu(i, hctx->tags->cpumask); + } } static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set *set) Patches currently in stable-queue which might be from akinobu.mita@gmail.com are queue-4.2/blk-mq-avoid-setting-hctx-tags-cpumask-before-allocation.patch