From patchwork Sat Nov 6 09:23:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 12606247 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E3B7BC433FE for ; Sat, 6 Nov 2021 09:11:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B4EA2611C1 for ; Sat, 6 Nov 2021 09:11:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233866AbhKFJNk (ORCPT ); Sat, 6 Nov 2021 05:13:40 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:30922 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231987AbhKFJNj (ORCPT ); Sat, 6 Nov 2021 05:13:39 -0400 Received: from dggemv711-chm.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4HmWgw3hGtzcb0P; Sat, 6 Nov 2021 17:06:04 +0800 (CST) Received: from kwepemm600009.china.huawei.com (7.193.23.164) by dggemv711-chm.china.huawei.com (10.1.198.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.15; Sat, 6 Nov 2021 17:10:51 +0800 Received: from huawei.com (10.175.127.227) by kwepemm600009.china.huawei.com (7.193.23.164) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.15; Sat, 6 Nov 2021 17:10:49 +0800 From: Yu Kuai To: , , , , CC: , , , , , , Subject: [PATCH] blk-mq: don't free tags if the tag_set is used by other device in queue initialztion Date: Sat, 6 Nov 2021 17:23:31 +0800 Message-ID: <20211106092331.3162749-1-yukuai3@huawei.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To kwepemm600009.china.huawei.com (7.193.23.164) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Our test report a UAF on v5.10: [ 1446.674930] ================================================================== [ 1446.675970] BUG: KASAN: use-after-free in blk_mq_get_driver_tag+0x9a4/0xa90 [ 1446.676902] Read of size 8 at addr ffff8880185afd10 by task kworker/1:2/12348 [ 1446.677851] [ 1446.678073] CPU: 1 PID: 12348 Comm: kworker/1:2 Not tainted 5.10.0-10177-gc9c81b1e346a #2 [ 1446.679168] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [ 1446.680692] Workqueue: kthrotld blk_throtl_dispatch_work_fn [ 1446.681448] Call Trace: [ 1446.681800] dump_stack+0x9b/0xce [ 1446.682259] ? blk_mq_get_driver_tag+0x9a4/0xa90 [ 1446.682916] print_address_description.constprop.6+0x3e/0x60 [ 1446.683688] ? __cpuidle_text_end+0x5/0x5 [ 1446.684239] ? vprintk_func+0x6b/0x120 [ 1446.684748] ? blk_mq_get_driver_tag+0x9a4/0xa90 [ 1446.685373] ? blk_mq_get_driver_tag+0x9a4/0xa90 [ 1446.685999] kasan_report.cold.9+0x22/0x3a [ 1446.686559] ? blk_mq_get_driver_tag+0x9a4/0xa90 [ 1446.687186] blk_mq_get_driver_tag+0x9a4/0xa90 [ 1446.687785] blk_mq_dispatch_rq_list+0x21a/0x1d40 [ 1446.688427] ? __sbitmap_get_word+0xc3/0xe0 [ 1446.688992] ? blk_mq_dequeue_from_ctx+0x960/0x960 [ 1446.689641] ? _raw_spin_lock+0x7a/0xd0 [ 1446.690164] ? _raw_spin_lock_irq+0xd0/0xd0 [ 1446.690727] ? sbitmap_get_shallow+0x3c9/0x4e0 [ 1446.691329] ? sbitmap_any_bit_set+0x128/0x190 [ 1446.691928] ? kyber_completed_request+0x290/0x290 [ 1446.692576] __blk_mq_do_dispatch_sched+0x394/0x830 [ 1446.693237] ? blk_mq_sched_request_inserted+0x100/0x100 [ 1446.693948] ? __blk_queue_split+0x31d/0x1380 [ 1446.694540] ? blk_integrity_merge_bio+0xc1/0x370 [ 1446.695182] ? ll_back_merge_fn+0x694/0x1490 [ 1446.695758] __blk_mq_sched_dispatch_requests+0x398/0x4f0 [ 1446.696484] ? bio_attempt_back_merge+0x1cc/0x340 [ 1446.697121] ? blk_mq_do_dispatch_ctx+0x570/0x570 [ 1446.697756] ? _raw_spin_lock+0x7a/0xd0 [ 1446.698279] blk_mq_sched_dispatch_requests+0xdf/0x140 [ 1446.698967] __blk_mq_run_hw_queue+0xc0/0x270 [ 1446.699561] __blk_mq_delay_run_hw_queue+0x4cc/0x550 [ 1446.700231] ? kyber_has_work+0x9a/0x140 [ 1446.700760] ? kyber_completed_request+0x290/0x290 [ 1446.701407] blk_mq_run_hw_queue+0x13b/0x2b0 [ 1446.701982] ? kyber_has_work+0x140/0x140 [ 1446.702593] blk_mq_sched_insert_requests+0x1de/0x390 [ 1446.703309] blk_mq_flush_plug_list+0x4b4/0x760 [ 1446.703946] ? blk_mq_insert_requests+0x4b0/0x4b0 [ 1446.704644] ? __bpf_trace_block_bio_complete+0x30/0x30 [ 1446.705408] blk_flush_plug_list+0x2c5/0x480 [ 1446.706026] ? blk_insert_cloned_request+0x460/0x460 [ 1446.706717] ? _raw_spin_lock_irq+0x7b/0xd0 [ 1446.707292] ? _raw_spin_lock_irqsave+0xe0/0xe0 [ 1446.707901] ? set_next_entity+0x235/0x2210 [ 1446.708471] blk_finish_plug+0x55/0xa0 [ 1446.708980] blk_throtl_dispatch_work_fn+0x23b/0x2e0 [ 1446.709653] ? tg_prfill_limit+0x8a0/0x8a0 [ 1446.710216] ? read_word_at_a_time+0xe/0x20 [ 1446.710780] ? strscpy+0x9a/0x320 [ 1446.711236] process_one_work+0x6d4/0xfe0 [ 1446.711778] worker_thread+0x91/0xc80 [ 1446.712281] ? __kthread_parkme+0xb0/0x110 [ 1446.712834] ? process_one_work+0xfe0/0xfe0 [ 1446.713400] kthread+0x32d/0x3f0 [ 1446.713840] ? kthread_park+0x170/0x170 [ 1446.714362] ret_from_fork+0x1f/0x30 [ 1446.714846] [ 1446.715062] Allocated by task 1: [ 1446.715509] kasan_save_stack+0x19/0x40 [ 1446.716026] __kasan_kmalloc.constprop.1+0xc1/0xd0 [ 1446.716673] blk_mq_init_tags+0x6d/0x330 [ 1446.717207] blk_mq_alloc_rq_map+0x50/0x1c0 [ 1446.717769] __blk_mq_alloc_map_and_request+0xe5/0x320 [ 1446.718459] blk_mq_alloc_tag_set+0x679/0xdc0 [ 1446.719050] scsi_add_host_with_dma.cold.3+0xa0/0x5db [ 1446.719736] virtscsi_probe+0x7bf/0xbd0 [ 1446.720265] virtio_dev_probe+0x402/0x6c0 [ 1446.720808] really_probe+0x276/0xde0 [ 1446.721320] driver_probe_device+0x267/0x3d0 [ 1446.721892] device_driver_attach+0xfe/0x140 [ 1446.722491] __driver_attach+0x13a/0x2c0 [ 1446.723037] bus_for_each_dev+0x146/0x1c0 [ 1446.723603] bus_add_driver+0x3fc/0x680 [ 1446.724145] driver_register+0x1c0/0x400 [ 1446.724693] init+0xa2/0xe8 [ 1446.725091] do_one_initcall+0x9e/0x310 [ 1446.725626] kernel_init_freeable+0xc56/0xcb9 [ 1446.726231] kernel_init+0x11/0x198 [ 1446.726714] ret_from_fork+0x1f/0x30 [ 1446.727212] [ 1446.727433] Freed by task 26992: [ 1446.727882] kasan_save_stack+0x19/0x40 [ 1446.728420] kasan_set_track+0x1c/0x30 [ 1446.728943] kasan_set_free_info+0x1b/0x30 [ 1446.729517] __kasan_slab_free+0x111/0x160 [ 1446.730084] kfree+0xb8/0x520 [ 1446.730507] blk_mq_free_map_and_requests+0x10b/0x1b0 [ 1446.731206] blk_mq_realloc_hw_ctxs+0x8cb/0x15b0 [ 1446.731844] blk_mq_init_allocated_queue+0x374/0x1380 [ 1446.732540] blk_mq_init_queue_data+0x7f/0xd0 [ 1446.733155] scsi_mq_alloc_queue+0x45/0x170 [ 1446.733730] scsi_alloc_sdev+0x73c/0xb20 [ 1446.734281] scsi_probe_and_add_lun+0x9a6/0x2d90 [ 1446.734916] __scsi_scan_target+0x208/0xc50 [ 1446.735500] scsi_scan_channel.part.3+0x113/0x170 [ 1446.736149] scsi_scan_host_selected+0x25a/0x360 [ 1446.736783] store_scan+0x290/0x2d0 [ 1446.737275] dev_attr_store+0x55/0x80 [ 1446.737782] sysfs_kf_write+0x132/0x190 [ 1446.738313] kernfs_fop_write_iter+0x319/0x4b0 [ 1446.738921] new_sync_write+0x40e/0x5c0 [ 1446.739429] vfs_write+0x519/0x720 [ 1446.739877] ksys_write+0xf8/0x1f0 [ 1446.740332] do_syscall_64+0x2d/0x40 [ 1446.740802] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1446.741462] [ 1446.741670] The buggy address belongs to the object at ffff8880185afd00 [ 1446.741670] which belongs to the cache kmalloc-256 of size 256 [ 1446.743276] The buggy address is located 16 bytes inside of [ 1446.743276] 256-byte region [ffff8880185afd00, ffff8880185afe00) [ 1446.744765] The buggy address belongs to the page: [ 1446.745416] page:ffffea0000616b00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x185ac [ 1446.746694] head:ffffea0000616b00 order:2 compound_mapcount:0 compound_pincount:0 [ 1446.747719] flags: 0x1fffff80010200(slab|head) [ 1446.748337] raw: 001fffff80010200 ffffea00006a3208 ffffea000061bf08 ffff88801004f240 [ 1446.749404] raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 [ 1446.750455] page dumped because: kasan: bad access detected [ 1446.751227] [ 1446.751445] Memory state around the buggy address: [ 1446.752102] ffff8880185afc00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 1446.753090] ffff8880185afc80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 1446.754079] >ffff8880185afd00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 1446.755065] ^ [ 1446.755589] ffff8880185afd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 1446.756574] ffff8880185afe00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 1446.757566] ================================================================== Flag 'BLK_MQ_F_TAG_QUEUE_SHARED' will be set if the second device on the same host initializes it's queue successfully. However, if the second device failed to allocate memory in blk_mq_alloc_and_init_hctx() from blk_mq_realloc_hw_ctxs() from blk_mq_init_allocated_queue(), __blk_mq_free_map_and_rqs() will be called on error path, and if 'BLK_MQ_TAG_HCTX_SHARED' is not set, 'tag_set->tags' will be freed while it's still used by the first device. Fix the problem by checking if 'tag_set->tag_list' is emptly before freeing 'tag_set->tag' during queue initialization. Fixes: 868f2f0b7206 ("blk-mq: dynamic h/w context count") Signed-off-by: Yu Kuai --- block/blk-mq.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 3527ee251a85..529ad8c47377 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -3571,7 +3571,7 @@ static struct blk_mq_hw_ctx *blk_mq_alloc_and_init_hctx( } static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set, - struct request_queue *q) + struct request_queue *q) { int i, j, end; struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx; @@ -3636,9 +3636,17 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set, for (; j < end; j++) { struct blk_mq_hw_ctx *hctx = hctxs[j]; + bool free_tags = !blk_mq_is_shared_tags(set->flags) && + !q->nr_hw_queues && list_empty(&set->tag_list); if (hctx) { - __blk_mq_free_map_and_rqs(set, j); + /* + * tags should not be freed if other device is using the + * tagset. q->nr_hw_queues is zero means current + * function is called from queue initialization. + */ + if (free_tags) + __blk_mq_free_map_and_rqs(set, j); blk_mq_exit_hctx(q, set, hctx, j); hctxs[j] = NULL; }