From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f77.google.com (mail-oo1-f77.google.com [209.85.161.77]) (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 BD9063955F1 for ; Mon, 31 Aug 2026 21:17:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.77 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788211064; cv=none; b=HH4cwFcyFtkhtuC2426b2EevHJukgoyzw4GbTNQ/klHdg9ewkSkHYvbMh+7euukSeOE8WzSgGsIQZXu10mPjU7u/t1iRM1GHlPYIolR+c89Vv67CmYbKbfRSyvN6KAf8oZweRisEet4cGnqkcP5wI+LNPRnB6ZA3ueTgGdCwXc0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788211064; c=relaxed/simple; bh=PBthaGqrwgMCY6KjQok+0WKbvRX8c4uy7DFThX/ixDw=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=ge486G4Pk/NMJ4/vTZVySwP8yrBQfPjqwBuTyhmmm2h96QS0lpV5M8fb5gtB3+ys2mbwWqMaNBkZp7qZSgd+6Ov+47BN+LosvRuZ97ZArAqBO+tnTmEbPBets8u22s7x/moNYZCfe5JA//fGRelWVs2JvDM3XnHBd/0fq5gZWJQ= 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=209.85.161.77 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-f77.google.com with SMTP id 006d021491bc7-6b173742296so366181eaf.0 for ; Mon, 31 Aug 2026 14:17:41 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788211060; x=1788815860; 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=tzKJl+jAZzWzqQaJuU3opchmm9TMZRwkBGCBYrBdkHw=; b=f7lfjMCreekwrVMUL6YzJG6SHIKU6UuslmAi6Ipm0i2rleOGO0I/3/rehGEDahYErT wmZ28g1rAdwYDZitveCl0fzxVVdVoxxUhbRLf9DwPpj5Y3zsPAIe9Y1adGnyWP3jipz+ rfYUqkAFOPHX6TjazUZUZ6DriaOZhtaC47O+L30eBLJHCK5LFCGWToRuh8yeAqhd0fW2 21+bBye/HsPm9itdirWofr/PVDIq0Ro1SEwBhk6cqkJ8j+x3TK7gyavGUHW7w1xARkhJ hj938eSiSOaAfQR0oInLaNiFDOy/YqpkE7XCEmAqV06ieqxBOH37yq0wO03BSJWqP3fX nJxQ== X-Forwarded-Encrypted: i=1; AHgh+Rr8lbWAsfcoZc3evu6jViXLbEONffq8kxdp012+3RzTGsOXIHg0VvDJkzTPKjVNWfDhf7zGaLZAh70SU9A=@vger.kernel.org X-Gm-Message-State: AFuF++mj8lMK7hy6VOgIJ1MGeK1AKDcdzlHNCkNthXztRBMMGkn3N1fE D1ZhpR2iaNID7JCuWWGQICJlEQJSaCHVgyp9OdVXMEpKOs/2TTOwDbU4h5pCMu5i990hNhcK9i1 ++pAuopEE/vPie5FfQnkN4JOOSpP1J7UPtSuUA9sXhvWqOAM9LltOx48zQ/Y= 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:f023:b0:6b1:51f3:abf with SMTP id 006d021491bc7-6b3786e9f9dmr924181eaf.15.1788211060388; Mon, 31 Aug 2026 14:17:40 -0700 (PDT) Date: Mon, 31 Aug 2026 14:17:40 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a95ef74.764875ec.b345.0003.GAE@google.com> Subject: [syzbot] [i2c?] [usb?] INFO: task hung in em28xx_i2c_unregister From: syzbot To: andi.shyti@kernel.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: a23cbb05744b Merge tag 'timers-urgent-2026-08-30' of git:/.. git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=12a6d379580000 kernel config: https://syzkaller.appspot.com/x/.config?x=5e4e3a0e188a497e dashboard link: https://syzkaller.appspot.com/bug?extid=f669f02a0fcc5b2148f2 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12d1f379580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/eed599d932fb/disk-a23cbb05.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/74e8c268c325/vmlinux-a23cbb05.xz kernel image: https://storage.googleapis.com/syzbot-assets/aa91aebf1baf/bzImage-a23cbb05.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+f669f02a0fcc5b2148f2@syzkaller.appspotmail.com INFO: task kworker/1:3:1865 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:3 state:D stack:22152 pid:1865 tgid:1865 ppid:2 task_flags:0x4288060 flags:0x00080000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7270 __schedule_loop kernel/sched/core.c:7347 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7362 schedule_timeout+0xc0/0x2c0 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:100 [inline] __wait_for_common kernel/sched/completion.c:121 [inline] wait_for_common kernel/sched/completion.c:132 [inline] wait_for_completion+0x2ca/0x5e0 kernel/sched/completion.c:153 i2c_del_adapter+0x281/0x430 drivers/i2c/i2c-core-base.c:1841 em28xx_i2c_unregister+0x4b/0x60 drivers/media/usb/em28xx/em28xx-i2c.c:1029 em28xx_release_resources+0x14c/0x240 drivers/media/usb/em28xx/em28xx-cards.c:3764 em28xx_usb_disconnect+0x19f/0x2f0 drivers/media/usb/em28xx/em28xx-cards.c:4455 usb_unbind_interface+0x295/0x9f0 drivers/usb/core/driver.c:461 device_remove drivers/base/dd.c:618 [inline] __device_release_driver drivers/base/dd.c:1349 [inline] device_release_driver_internal+0x4f5/0x880 drivers/base/dd.c:1372 bus_remove_device+0x444/0x560 drivers/base/bus.c:664 device_del+0x524/0x8f0 drivers/base/core.c:3965 usb_disable_device+0x3d4/0x8d0 drivers/usb/core/message.c:1478 usb_disconnect+0x346/0x9a0 drivers/usb/core/hub.c:2350 hub_port_connect drivers/usb/core/hub.c:5420 [inline] hub_port_connect_change drivers/usb/core/hub.c:5720 [inline] port_event drivers/usb/core/hub.c:5884 [inline] hub_event+0x1bbb/0x4d30 drivers/usb/core/hub.c:5966 process_one_work kernel/workqueue.c:3387 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3470 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3551 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 INFO: task syz.4.136:6293 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.136 state:D stack:27896 pid:6293 tgid:6293 ppid:5809 task_flags:0x400040 flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7270 __schedule_loop kernel/sched/core.c:7347 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7362 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7419 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821 device_lock include/linux/device.h:1104 [inline] usbdev_release+0x80/0x780 drivers/usb/core/devio.c:1099 __fput+0x418/0xa50 fs/file_table.c:512 task_work_run+0x1d9/0x270 kernel/task_work.c:233 ptrace_notify+0x27c/0x2b0 kernel/signal.c:2524 ptrace_report_syscall include/linux/ptrace.h:416 [inline] ptrace_report_syscall_exit+0x2d/0x50 include/linux/ptrace.h:477 arch_ptrace_report_syscall_exit include/linux/entry-common.h:233 [inline] syscall_exit_work include/linux/entry-common.h:266 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:297 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:334 [inline] do_syscall_64+0x4a0/0x520 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd16879e159 RSP: 002b:00007fd168b4fba8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007fd168b4fc90 RCX: 00007fd16879e159 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 000000000004d940 R08: 0000000000000001 R09: 0000000000000000 R10: 0000001b2e620000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd168a25fac R14: 00007fd168a25fa8 R15: 00007fd168a25fa0 INFO: task syz.2.135:6294 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.2.135 state:D stack:27096 pid:6294 tgid:6294 ppid:5785 task_flags:0x400040 flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7270 __schedule_loop kernel/sched/core.c:7347 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7362 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7419 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821 device_lock include/linux/device.h:1104 [inline] usbdev_release+0x80/0x780 drivers/usb/core/devio.c:1099 __fput+0x418/0xa50 fs/file_table.c:512 task_work_run+0x1d9/0x270 kernel/task_work.c:233 ptrace_notify+0x27c/0x2b0 kernel/signal.c:2524 ptrace_report_syscall include/linux/ptrace.h:416 [inline] ptrace_report_syscall_exit+0x2d/0x50 include/linux/ptrace.h:477 arch_ptrace_report_syscall_exit include/linux/entry-common.h:233 [inline] syscall_exit_work include/linux/entry-common.h:266 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:297 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:334 [inline] do_syscall_64+0x4a0/0x520 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1b3299e159 RSP: 002b:00007f1b32d4fba8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f1b32d4fc90 RCX: 00007f1b3299e159 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 000000000004d997 R08: 0000000000000001 R09: 0000000000000000 R10: 0000001b2d220000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1b32c25fac R14: 00007f1b32c25fa8 R15: 00007f1b32c25fa0 INFO: task syz.5.133:6295 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.5.133 state:D stack:27096 pid:6295 tgid:6295 ppid:5796 task_flags:0x400040 flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7270 __schedule_loop kernel/sched/core.c:7347 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7362 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7419 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821 device_lock include/linux/device.h:1104 [inline] usbdev_release+0x80/0x780 drivers/usb/core/devio.c:1099 __fput+0x418/0xa50 fs/file_table.c:512 task_work_run+0x1d9/0x270 kernel/task_work.c:233 ptrace_notify+0x27c/0x2b0 kernel/signal.c:2524 ptrace_report_syscall include/linux/ptrace.h:416 [inline] ptrace_report_syscall_exit+0x2d/0x50 include/linux/ptrace.h:477 arch_ptrace_report_syscall_exit include/linux/entry-common.h:233 [inline] syscall_exit_work include/linux/entry-common.h:266 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:297 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:334 [inline] do_syscall_64+0x4a0/0x520 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe6b1f9e159 RSP: 002b:00007fe6b234fba8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007fe6b234fc90 RCX: 00007fe6b1f9e159 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 000000000004d99d R08: 0000000000000001 R09: 0000000000000000 R10: 0000001b2dd20000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe6b2225fac R14: 00007fe6b2225fa8 R15: 00007fe6b2225fa0 INFO: task syz.0.132:6296 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.132 state:D stack:27096 pid:6296 tgid:6296 ppid:5770 task_flags:0x400040 flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7270 __schedule_loop kernel/sched/core.c:7347 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7362 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7419 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821 device_lock include/linux/device.h:1104 [inline] usbdev_release+0x80/0x780 drivers/usb/core/devio.c:1099 __fput+0x418/0xa50 fs/file_table.c:512 task_work_run+0x1d9/0x270 kernel/task_work.c:233 ptrace_notify+0x27c/0x2b0 kernel/signal.c:2524 ptrace_report_syscall include/linux/ptrace.h:416 [inline] ptrace_report_syscall_exit+0x2d/0x50 include/linux/ptrace.h:477 arch_ptrace_report_syscall_exit include/linux/entry-common.h:233 [inline] syscall_exit_work include/linux/entry-common.h:266 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:297 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:334 [inline] do_syscall_64+0x4a0/0x520 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa0c859e159 RSP: 002b:00007fa0c894fba8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007fa0c894fc90 RCX: 00007fa0c859e159 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 000000000004d9a7 R08: 0000000000000001 R09: 0000000000000000 R10: 0000001b2c820000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa0c8825fac R14: 00007fa0c8825fa8 R15: 00007fa0c8825fa0 INFO: task syz.1.134:6297 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.134 state:D stack:27592 pid:6297 tgid:6297 ppid:5775 task_flags:0x400040 flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7270 __schedule_loop kernel/sched/core.c:7347 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7362 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7419 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821 device_lock include/linux/device.h:1104 [inline] usbdev_release+0x80/0x780 drivers/usb/core/devio.c:1099 __fput+0x418/0xa50 fs/file_table.c:512 task_work_run+0x1d9/0x270 kernel/task_work.c:233 ptrace_notify+0x27c/0x2b0 kernel/signal.c:2524 ptrace_report_syscall include/linux/ptrace.h:416 [inline] ptrace_report_syscall_exit+0x2d/0x50 include/linux/ptrace.h:477 arch_ptrace_report_syscall_exit include/linux/entry-common.h:233 [inline] syscall_exit_work include/linux/entry-common.h:266 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:297 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:334 [inline] do_syscall_64+0x4a0/0x520 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa70379e159 RSP: 002b:00007fa703b4fba8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007fa703b4fc90 RCX: 00007fa70379e159 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 000000000004d9ba R08: 0000000000000001 R09: 0000000000000000 R10: 0000001b2cb20000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa703a25fac R14: 00007fa703a25fa8 R15: 00007fa703a25fa0 Showing all locks held in the system: locks held by pr/ttyS0/16: 2, last CPU#1: #0: ffffffff8ec362b8 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:314 [inline] #0: ffffffff8ec362b8 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:439 [inline] #0: ffffffff8ec362b8 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60 kernel/printk/printk.c:291 #1: ffffffff9ad31098 (&port_lock_key){-...}-{3:3}, at: __uart_port_lock_irqsave include/linux/serial_core.h:613 [inline] #1: ffffffff9ad31098 (&port_lock_key){-...}-{3:3}, at: univ8250_console_device_lock+0x67/0xc0 drivers/tty/serial/8250/8250_core.c:413 locks held by khungtaskd/32: 1, last CPU#0: #0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6837 locks held by kworker/1:3/1865: 6, on CPU#1: #0: ffff8880232e7140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffff8880232e7140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffff8880232e7140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3352 [inline] #0: ffff8880232e7140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3470 #1: ffffc900063f7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #1: ffffc900063f7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffc900063f7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3352 [inline] #1: ffffc900063f7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3470 #2: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #2: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5912 #3: ffff888024c051d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #3: ffff888024c051d8 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0xfc/0x9a0 drivers/usb/core/hub.c:2341 #4: ffff88802b4031a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #4: ffff88802b4031a0 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1171 [inline] #4: ffff88802b4031a0 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb9/0x880 drivers/base/dd.c:1369 #5: ffff888058201cf0 (&dev->lock#3){+.+.}-{4:4}, at: em28xx_release_resources+0x75/0x240 drivers/media/usb/em28xx/em28xx-cards.c:3758 locks held by getty/5374: 2, on CPU#0: #0: ffff888036cae0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211 locks held by udevd/6066: 4, on CPU#1: #0: ffff888035016f38 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xa4/0xca0 fs/seq_file.c:183 #1: ffff888055824c80 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5d/0x420 fs/kernfs/file.c:165 #2: ffff88807ff67a58 (kn->active#28){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff88807ff67a58 (kn->active#28){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:166 #3: ffff888024c051d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1109 [inline] #3: ffff888024c051d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 locks held by syz.4.136/6293: 1, on CPU#0: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_release+0x80/0x780 drivers/usb/core/devio.c:1099 locks held by syz.2.135/6294: 1, on CPU#0: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_release+0x80/0x780 drivers/usb/core/devio.c:1099 locks held by syz.5.133/6295: 1, on CPU#1: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_release+0x80/0x780 drivers/usb/core/devio.c:1099 locks held by syz.0.132/6296: 1, on CPU#1: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_release+0x80/0x780 drivers/usb/core/devio.c:1099 locks held by syz.1.134/6297: 1, on CPU#1: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_release+0x80/0x780 drivers/usb/core/devio.c:1099 locks held by syz.6.137/6384: 1, on CPU#1: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.7.138/6385: 1, on CPU#1: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.8.139/6386: 1, on CPU#0: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.9.140/6387: 1, on CPU#0: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.3.141/6388: 1, on CPU#1: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.0.142/6484: 1, on CPU#1: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.1.143/6485: 1, on CPU#0: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.2.144/6486: 1, on CPU#0: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.4.146/6490: 1, on CPU#1: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.6.150/6564: 1, on CPU#1: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.7.151/6565: 1, on CPU#1: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.8.153/6566: 1, on CPU#1: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.9.154/6567: 1, on CPU#0: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.3.162/6643: 1, on CPU#1: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.0.163/6645: 1, on CPU#0: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.1.164/6646: 1, on CPU#1: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.2.166/6648: 1, on CPU#1: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.4.174/6724: 1, on CPU#1: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.7.176/6725: 1, on CPU#0: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.6.175/6726: 1, on CPU#1: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 locks held by syz.8.178/6727: 1, on CPU#0: #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #0: ffff88802a64a1d8 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x151/0x770 drivers/usb/core/devio.c:1054 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 32 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123 nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66 trigger_all_cpu_backtrace include/linux/nmi.h:164 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline] watchdog+0xfd7/0x1030 kernel/hung_task.c:561 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 16 Comm: pr/ttyS0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:409 Code: e8 5e e2 55 fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 af ab c5 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 1a e4 74 06 cc 44 89 f9 80 e1 07 RSP: 0018:ffffc900001578b8 EFLAGS: 00000002 RAX: 1ffffffff35a6200 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020 RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: ffffffff8571d400 R12: dffffc0000000000 R13: 0000000000000000 R14: ffffffff9ad310c0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124dda000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe39d825fa4 CR3: 000000006a5fc000 CR4: 00000000003526f0 Call Trace: serial_in drivers/tty/serial/8250/8250.h:128 [inline] serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline] wait_for_lsr+0x184/0x2f0 drivers/tty/serial/8250/8250_port.c:2013 serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3270 [inline] __serial8250_console_fifo_write+0x346/0x3e0 drivers/tty/serial/8250/8250_port.c:3372 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3378 [inline] __serial8250_console_write drivers/tty/serial/8250/8250_port.c:3429 [inline] serial8250_console_write+0xaa1/0x1200 drivers/tty/serial/8250/8250_port.c:3493 nbcon_emit_next_record+0xef5/0x1a90 kernel/printk/nbcon.c:-1 nbcon_emit_one kernel/printk/nbcon.c:1157 [inline] nbcon_kthread_func+0x679/0x880 kernel/printk/nbcon.c:1271 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 --- 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 syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. 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