From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f78.google.com (mail-oo1-f78.google.com [209.85.161.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C16DB44A3EF for ; Wed, 2 Sep 2026 18:25:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.78 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788373537; cv=none; b=ewzDUo8ZH0lzhMk7xCzcxMGl/+2wSjYNiW0YgIhTraq20U4n5tu5AzgAEc64xCKszNzUNPc3S2TuQnrt2gdC9RT04oJIEfZzPhyWL+uWHslDqjvcY4D0tMqhkvXy9amfzMfVOSsxbji7nmO2v8VcBnmtQLKihk4Bu6R/uK+jU+c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788373537; c=relaxed/simple; bh=AAr6+E1y4y2pBBf5f/au/7TNHvKoFu+cwfQlgDm8heE=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=fVOU0A3T3O5Ntqh/xYsItziT4ggfdHAeSFvpw/+ON+Ci2GNF42CLVxqf0JSQuwz1NEeIK0RzCUOUzCyDIIW349OZKuumy24o5CwOdGLbqndf3LVExSzIhKJ3axAX1/YLCoyDm9XJ1DMsVpOyH2by05aIf9LfAWV9l51iJU7ghek= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.78 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f78.google.com with SMTP id 006d021491bc7-6b0e7370be1so206635eaf.0 for ; Wed, 02 Sep 2026 11:25:35 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788373534; x=1788978334; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=4SnPbsxDO3W40hbAE1g6nz4DIsFHz/xmSs6V4dMsXXg=; b=rpoqu1pU5UBfoV4zC7F7EK3iFVnpFnGVQzvGGuicE43NSqIFJn+a4K4Yv9WYmrdgGR YhZtUw8llaNIRlodQtmxKD8D53ky7lOf0+sFGjJNw0XVzU2ilnRM3TiqyzgGbEB2iiLz BTbOeypCgd2Jg1i+kKXbG7pCK0v1TOiWTUgQur959f7vTYjshY3cpogaV1dLNGJQ5wZC U+BICzD6tn13rADkiRv/8NjE/TcZvj6DvM1JwCy/mf7Pd1EBvsm2362BuPyiz1+18ffD yJQRDovLzqL/NxXYsQxJAjBb+MkhEs6uWMAo41QPYhCOMwZFuCIXD4r/axYlOlzeL/U9 XCrA== X-Forwarded-Encrypted: i=1; AHgh+RpznOZ0BRtatpXK4WV3MVwrhEenpsvllPa4QxsxQNORamxHlubcGc5Iok5ab/0jlDzqQV0xbYMBC60yghM=@vger.kernel.org X-Gm-Message-State: AFuF++mxQNkU5kLbMMMVQjBCjnRRQ/CVjaLBVSIqENltUUbHmorQ080j FB6tw/vPQSAeh3WvOO/LsyOjTjLUuJSQcGXD7RSTTAEP6hRkSrE+lMIwbrgEGvk0wEHa2wcmCfP ieVPjebbgIIrrSTUBE8VxJGGsOVn9kkbK0pIWNbN95+7VZr59uZq8I/L3CsY= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:a06:b0:6b1:a146:1297 with SMTP id 006d021491bc7-6b582a61ba0mr1096925eaf.1.1788373534597; Wed, 02 Sep 2026 11:25:34 -0700 (PDT) Date: Wed, 02 Sep 2026 11:25:34 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a986a1e.27a413cd.1e878c.000e.GAE@google.com> Subject: [syzbot] [block?] possible deadlock in queue_requests_store (3) From: syzbot To: axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 45c13f3f9e3b Merge tag 'hwlock-v7.3' of git://git.kernel.o.. git tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master console output: https://syzkaller.appspot.com/x/log.txt?x=1755ae25580000 kernel config: https://syzkaller.appspot.com/x/.config?x=d6a4e008e57a0e64 dashboard link: https://syzkaller.appspot.com/bug?extid=65e679ca2c660840635a compiler: aarch64-linux-gnu-gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 userspace arch: arm64 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/fa3fbcfdac58/non_bootable_disk-45c13f3f.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/de92b7834d98/vmlinux-45c13f3f.xz kernel image: https://storage.googleapis.com/syzbot-assets/cc3fde89c915/Image-45c13f3f.gz.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+65e679ca2c660840635a@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G W L ------------------------------------------------------ syz.4.3610/13943 is trying to acquire lock: ffff000015008580 (&q->elevator_lock){+.+.}-{4:4}, at: queue_requests_store+0x28c/0x4e0 block/blk-sysfs.c:124 but task is already holding lock: ffff000015008060 (&q->q_usage_counter(io)#51){++++}-{0:0}, at: blk_mq_freeze_queue_nomemsave+0x18/0x30 block/blk-mq.c:206 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&q->q_usage_counter(io)#51){++++}-{0:0}: lock_acquire kernel/locking/lockdep.c:5886 [inline] lock_acquire+0x3d0/0x44c kernel/locking/lockdep.c:5843 blk_alloc_queue+0x4e0/0x640 block/blk-core.c:504 blk_mq_alloc_queue+0x148/0x224 block/blk-mq.c:4420 __blk_mq_alloc_disk+0x20/0x120 block/blk-mq.c:4467 null_add_dev+0x9bc/0x17a8 drivers/block/null_blk/main.c:2017 null_create_dev drivers/block/null_blk/main.c:2114 [inline] null_init+0x248/0x2f4 drivers/block/null_blk/main.c:2178 do_one_initcall+0x134/0xb20 init/main.c:1357 do_initcall_level init/main.c:1419 [inline] do_initcalls init/main.c:1435 [inline] do_basic_setup init/main.c:1455 [inline] kernel_init_freeable+0x5ec/0x670 init/main.c:1670 kernel_init+0x2c/0x14c init/main.c:1560 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:854 -> #3 (fs_reclaim){+.+.}-{0:0}: lock_acquire kernel/locking/lockdep.c:5886 [inline] lock_acquire+0x3d0/0x44c kernel/locking/lockdep.c:5843 __fs_reclaim_acquire mm/page_alloc.c:4375 [inline] fs_reclaim_acquire+0x130/0x158 mm/page_alloc.c:4389 might_alloc include/linux/sched/mm.h:316 [inline] slab_pre_alloc_hook mm/slub.c:4636 [inline] slab_alloc_node mm/slub.c:4974 [inline] __kmalloc_cache_node_noprof+0x6c/0x634 mm/slub.c:5578 _kmalloc_node_noprof include/linux/slab.h:1196 [inline] __get_vm_area_node+0x118/0x2ec mm/vmalloc.c:3238 __vmalloc_node_range_noprof+0x198/0x1024 mm/vmalloc.c:4065 __vmalloc_node_noprof+0xe4/0x14c mm/vmalloc.c:4166 vmalloc_noprof+0x24/0x30 mm/vmalloc.c:4201 mtdblock_writesect+0x41c/0x5b8 drivers/mtd/mtdblock.c:242 do_blktrans_request drivers/mtd/mtd_blkdevs.c:88 [inline] mtd_blktrans_work drivers/mtd/mtd_blkdevs.c:152 [inline] mtd_queue_rq+0x744/0x1694 drivers/mtd/mtd_blkdevs.c:179 blk_mq_dispatch_rq_list+0x2e0/0x177c block/blk-mq.c:2117 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline] blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline] __blk_mq_sched_dispatch_requests+0x830/0xe60 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0x7c/0x114 block/blk-mq-sched.c:329 blk_mq_run_work_fn+0xf0/0x278 block/blk-mq.c:2531 process_one_work+0x830/0x1c00 kernel/workqueue.c:3387 process_scheduled_works kernel/workqueue.c:3470 [inline] worker_thread+0x42c/0xc90 kernel/workqueue.c:3551 kthread+0x2ec/0x384 kernel/kthread.c:436 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:854 -> #2 (&new->lock){+.+.}-{4:4}: lock_acquire kernel/locking/lockdep.c:5886 [inline] lock_acquire+0x3d0/0x44c kernel/locking/lockdep.c:5843 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x150/0x1530 kernel/locking/mutex.c:821 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:874 mtd_blktrans_work drivers/mtd/mtd_blkdevs.c:151 [inline] mtd_queue_rq+0x2a4/0x1694 drivers/mtd/mtd_blkdevs.c:179 blk_mq_dispatch_rq_list+0x2e0/0x177c block/blk-mq.c:2117 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline] blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline] __blk_mq_sched_dispatch_requests+0x830/0xe60 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0x7c/0x114 block/blk-mq-sched.c:329 blk_mq_run_work_fn+0xf0/0x278 block/blk-mq.c:2531 process_one_work+0x830/0x1c00 kernel/workqueue.c:3387 process_scheduled_works kernel/workqueue.c:3470 [inline] worker_thread+0x42c/0xc90 kernel/workqueue.c:3551 kthread+0x2ec/0x384 kernel/kthread.c:436 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:854 -> #1 (set->srcu){.+.+}-{0:0}: lock_sync+0xf0/0x16c kernel/locking/lockdep.c:5934 srcu_lock_sync include/linux/srcu.h:210 [inline] __synchronize_srcu+0xa8/0x280 kernel/rcu/srcutree.c:1462 synchronize_srcu_expedited kernel/rcu/srcutree.c:1502 [inline] synchronize_srcu+0x168/0x7d0 kernel/rcu/srcutree.c:1558 blk_mq_wait_quiesce_done block/blk-mq.c:284 [inline] blk_mq_wait_quiesce_done block/blk-mq.c:281 [inline] blk_mq_quiesce_queue block/blk-mq.c:304 [inline] blk_mq_quiesce_queue+0xf4/0x160 block/blk-mq.c:299 elevator_switch+0x118/0x430 block/elevator.c:576 elevator_change+0x294/0x420 block/elevator.c:681 elevator_set_default+0x210/0x2b8 block/elevator.c:754 blk_register_queue+0x36c/0x500 block/blk-sysfs.c:992 __add_disk+0x510/0xb48 block/genhd.c:524 add_disk_fwnode+0x110/0x3e0 block/genhd.c:593 device_add_disk+0x14/0x20 block/genhd.c:623 add_disk include/linux/blkdev.h:798 [inline] nbd_dev_add+0x5f8/0x9b4 drivers/block/nbd.c:2026 nbd_init+0x190/0x1b0 drivers/block/nbd.c:2743 do_one_initcall+0x134/0xb20 init/main.c:1357 do_initcall_level init/main.c:1419 [inline] do_initcalls init/main.c:1435 [inline] do_basic_setup init/main.c:1455 [inline] kernel_init_freeable+0x5ec/0x670 init/main.c:1670 kernel_init+0x2c/0x14c init/main.c:1560 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:854 -> #0 (&q->elevator_lock){+.+.}-{4:4}: check_prev_add+0x114/0xca0 kernel/locking/lockdep.c:3181 check_prevs_add kernel/locking/lockdep.c:3300 [inline] validate_chain kernel/locking/lockdep.c:3924 [inline] __lock_acquire+0x13f4/0x1a5c kernel/locking/lockdep.c:5253 lock_acquire kernel/locking/lockdep.c:5886 [inline] lock_acquire+0x3d0/0x44c kernel/locking/lockdep.c:5843 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x150/0x1530 kernel/locking/mutex.c:821 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:874 queue_requests_store+0x28c/0x4e0 block/blk-sysfs.c:124 queue_attr_store+0x1f8/0x260 block/blk-sysfs.c:906 sysfs_kf_write+0xc4/0x10c fs/sysfs/file.c:145 kernfs_fop_write_iter+0x2a4/0x460 fs/kernfs/file.c:345 do_iter_readv_writev+0x3d8/0x6dc fs/read_write.c:828 vfs_writev+0x258/0x6e8 fs/read_write.c:1058 do_writev+0xfc/0x280 fs/read_write.c:1104 __do_sys_writev fs/read_write.c:1172 [inline] __se_sys_writev fs/read_write.c:1169 [inline] __arm64_sys_writev+0x74/0xa4 fs/read_write.c:1169 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x74/0x240 arch/arm64/kernel/syscall.c:49 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:121 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x58/0x2a4 arch/arm64/kernel/entry-common.c:758 el0t_64_sync_handler+0xa0/0xe4 arch/arm64/kernel/entry-common.c:777 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590 other info that might help us debug this: Chain exists of: &q->elevator_lock --> fs_reclaim --> &q->q_usage_counter(io)#51 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&q->q_usage_counter(io)#51); lock(fs_reclaim); lock(&q->q_usage_counter(io)#51); lock(&q->elevator_lock); *** DEADLOCK *** locks held by syz.4.3610/13943: 7, last CPU#0: #0: ffff00001466cef0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x1e4/0x294 fs/file.c:1259 #1: ffff00002894a460 (sb_writers#7){.+.+}-{0:0}, at: percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline] #1: ffff00002894a460 (sb_writers#7){.+.+}-{0:0}, at: __sb_start_write include/linux/fs/super.h:19 [inline] #1: ffff00002894a460 (sb_writers#7){.+.+}-{0:0}, at: sb_start_write include/linux/fs/super.h:125 [inline] #1: ffff00002894a460 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2754 [inline] #1: ffff00002894a460 (sb_writers#7){.+.+}-{0:0}, at: vfs_writev+0x3c8/0x6e8 fs/read_write.c:1056 #2: ffff000015b25c80 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1e4/0x460 fs/kernfs/file.c:336 #3: ffff00001554ce18 (kn->active#61){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #3: ffff00001554ce18 (kn->active#61){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x460 fs/kernfs/file.c:337 #4: ffff0000155951f8 (&set->update_nr_hwq_lock){++++}-{4:4}, at: queue_requests_store+0xe4/0x4e0 block/blk-sysfs.c:88 #5: ffff000015008060 (&q->q_usage_counter(io)#51){++++}-{0:0}, at: blk_mq_freeze_queue_nomemsave+0x18/0x30 block/blk-mq.c:206 #6: ffff000015008098 (&q->q_usage_counter(queue)#34){+.+.}-{0:0}, at: blk_mq_freeze_queue_nomemsave+0x18/0x30 block/blk-mq.c:206 stack backtrace: CPU: 0 UID: 0 PID: 13943 Comm: syz.4.3610 Tainted: G W L syzkaller #0 PREEMPT Tainted: [W]=WARN, [L]=SOFTLOCKUP Hardware name: linux,dummy-virt (DT) Call trace: show_stack+0x18/0x24 arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x7c/0xb0 lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x23c/0x284 kernel/locking/lockdep.c:2059 check_noncircular+0x174/0x194 kernel/locking/lockdep.c:2191 check_prev_add+0x114/0xca0 kernel/locking/lockdep.c:3181 check_prevs_add kernel/locking/lockdep.c:3300 [inline] validate_chain kernel/locking/lockdep.c:3924 [inline] __lock_acquire+0x13f4/0x1a5c kernel/locking/lockdep.c:5253 lock_acquire kernel/locking/lockdep.c:5886 [inline] lock_acquire+0x3d0/0x44c kernel/locking/lockdep.c:5843 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x150/0x1530 kernel/locking/mutex.c:821 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:874 queue_requests_store+0x28c/0x4e0 block/blk-sysfs.c:124 queue_attr_store+0x1f8/0x260 block/blk-sysfs.c:906 sysfs_kf_write+0xc4/0x10c fs/sysfs/file.c:145 kernfs_fop_write_iter+0x2a4/0x460 fs/kernfs/file.c:345 do_iter_readv_writev+0x3d8/0x6dc fs/read_write.c:828 vfs_writev+0x258/0x6e8 fs/read_write.c:1058 do_writev+0xfc/0x280 fs/read_write.c:1104 __do_sys_writev fs/read_write.c:1172 [inline] __se_sys_writev fs/read_write.c:1169 [inline] __arm64_sys_writev+0x74/0xa4 fs/read_write.c:1169 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x74/0x240 arch/arm64/kernel/syscall.c:49 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:121 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x58/0x2a4 arch/arm64/kernel/entry-common.c:758 el0t_64_sync_handler+0xa0/0xe4 arch/arm64/kernel/entry-common.c:777 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup