Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753574AbdFLPbR (ORCPT ); Mon, 12 Jun 2017 11:31:17 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:40330 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752700AbdFLPbN (ORCPT ); Mon, 12 Jun 2017 11:31:13 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bart Van Assche , Tejun Heo , Hannes Reinecke , Christoph Hellwig , Jan Kara , Jens Axboe Subject: [PATCH 4.11 087/150] block: Avoid that blk_exit_rl() triggers a use-after-free Date: Mon, 12 Jun 2017 17:24:54 +0200 Message-Id: <20170612152523.116336194@linuxfoundation.org> X-Mailer: git-send-email 2.13.1 In-Reply-To: <20170612152519.404936272@linuxfoundation.org> References: <20170612152519.404936272@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3834 Lines: 115 4.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bart Van Assche commit b425e50492583b10cceb388af36ef0bd3bdf842a upstream. Since the introduction of .init_rq_fn() and .exit_rq_fn() it is essential that the memory allocated for struct request_queue stays around until all blk_exit_rl() calls have finished. Hence make blk_init_rl() take a reference on struct request_queue. This patch fixes the following crash: general protection fault: 0000 [#2] SMP CPU: 3 PID: 28 Comm: ksoftirqd/3 Tainted: G D 4.12.0-rc2-dbg+ #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014 task: ffff88013a108040 task.stack: ffffc9000071c000 RIP: 0010:free_request_size+0x1a/0x30 RSP: 0018:ffffc9000071fd38 EFLAGS: 00010202 RAX: 6b6b6b6b6b6b6b6b RBX: ffff880067362a88 RCX: 0000000000000003 RDX: ffff880067464178 RSI: ffff880067362a88 RDI: ffff880135ea4418 RBP: ffffc9000071fd40 R08: 0000000000000000 R09: 0000000100180009 R10: ffffc9000071fd38 R11: ffffffff81110800 R12: ffff88006752d3d8 R13: ffff88006752d3d8 R14: ffff88013a108040 R15: 000000000000000a FS: 0000000000000000(0000) GS:ffff88013fd80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa8ec1edb00 CR3: 0000000138ee8000 CR4: 00000000001406e0 Call Trace: mempool_destroy.part.10+0x21/0x40 mempool_destroy+0xe/0x10 blk_exit_rl+0x12/0x20 blkg_free+0x4d/0xa0 __blkg_release_rcu+0x59/0x170 rcu_process_callbacks+0x260/0x4e0 __do_softirq+0x116/0x250 smpboot_thread_fn+0x123/0x1e0 kthread+0x109/0x140 ret_from_fork+0x31/0x40 Fixes: commit e9c787e65c0c ("scsi: allocate scsi_cmnd structures as part of struct request") Signed-off-by: Bart Van Assche Acked-by: Tejun Heo Reviewed-by: Hannes Reinecke Reviewed-by: Christoph Hellwig Cc: Jan Kara Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- block/blk-cgroup.c | 2 +- block/blk-core.c | 10 ++++++++-- block/blk-sysfs.c | 2 +- block/blk.h | 2 +- 4 files changed, 11 insertions(+), 5 deletions(-) --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -74,7 +74,7 @@ static void blkg_free(struct blkcg_gq *b blkcg_policy[i]->pd_free_fn(blkg->pd[i]); if (blkg->blkcg != &blkcg_root) - blk_exit_rl(&blkg->rl); + blk_exit_rl(blkg->q, &blkg->rl); blkg_rwstat_exit(&blkg->stat_ios); blkg_rwstat_exit(&blkg->stat_bytes); --- a/block/blk-core.c +++ b/block/blk-core.c @@ -643,13 +643,19 @@ int blk_init_rl(struct request_list *rl, if (!rl->rq_pool) return -ENOMEM; + if (rl != &q->root_rl) + WARN_ON_ONCE(!blk_get_queue(q)); + return 0; } -void blk_exit_rl(struct request_list *rl) +void blk_exit_rl(struct request_queue *q, struct request_list *rl) { - if (rl->rq_pool) + if (rl->rq_pool) { mempool_destroy(rl->rq_pool); + if (rl != &q->root_rl) + blk_put_queue(q); + } } struct request_queue *blk_alloc_queue(gfp_t gfp_mask) --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -819,7 +819,7 @@ static void blk_release_queue(struct kob elevator_exit(q, q->elevator); } - blk_exit_rl(&q->root_rl); + blk_exit_rl(q, &q->root_rl); if (q->queue_tags) __blk_queue_free_tags(q); --- a/block/blk.h +++ b/block/blk.h @@ -59,7 +59,7 @@ void blk_free_flush_queue(struct blk_flu int blk_init_rl(struct request_list *rl, struct request_queue *q, gfp_t gfp_mask); -void blk_exit_rl(struct request_list *rl); +void blk_exit_rl(struct request_queue *q, struct request_list *rl); void init_request_from_bio(struct request *req, struct bio *bio); void blk_rq_bio_prep(struct request_queue *q, struct request *rq, struct bio *bio);