From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-il1-f206.google.com (mail-il1-f206.google.com [209.85.166.206]) (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 D91A11A0BF3 for ; Sun, 22 Jun 2025 11:13:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.206 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750590802; cv=none; b=rs/4xepvolyp6SafXLFuFhZ824R4Hf/GSsEnb+koOWaDA//BDgIZdiGfEvwICU2utURXt1xPUQhkldZ6RMU2544Rktbek2WtDeNTnmBoHxYb9PiMpvEKI5g33tP1yoSmcArnlopbbM5+qUbkpILS88D3rWf+t8HWGKNxKZBC93w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750590802; c=relaxed/simple; bh=pm3A01ewk32EiC/F0Pad9br1lPBmIU3MENY3LDPUTCQ=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=MCTE4ileSJPPNcdCnu7/FFy6QFaRfEgTefVYzkga+jKxz9vIAgZbbRd1HBrgTrylcAnd9TOiDwqb81njkH2HzpHhBY/K/slg7GlEObkRgQRBkmeT0snD3k0s8BPic0XnUZUoQVhuS4hRerqT28XsQkXSAwyMY/eefcf6Zq+HHGY= 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=209.85.166.206 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-il1-f206.google.com with SMTP id e9e14a558f8ab-3ddd5cd020dso74529395ab.0 for ; Sun, 22 Jun 2025 04:13:19 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1750590799; x=1751195599; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=soD6h5Yg5UXvYj3hUJ+UCIQjJVcZzTThZZ4L/y9UZiw=; b=YZIZg1EWPa9m+6TKcgV5tM70PERzUXwhUvaBovfWlIrLCsz2/EPSibwmoKFJRGGe+O nzfUSBGBVxltx+Ty0L5bdHIx9PK5U+jpMEAwaAOB1S06VFv1YYYMTt1d4OVj3AzgBuRt sLhC0G9+aWShoVTtG8dne9/FIMXrx9uLPdfwMb6u8XUymFjSPAIfEBXdx9Fpr6VfVHGy QU3xYByuBBPyuJfYRE38indGmvut8z5H75DNBJIHPPGr//ejR/dXDAQ0VxbyIU8U0esE kyDU1kT5t3HbEb4GwnvuvSdKMun3nIfXLAV+jlZLoAK1HnV5WuONFMKzacLmzyag2yRQ pyVA== X-Forwarded-Encrypted: i=1; AJvYcCUzscyZlKF3nPQGuZLVUBbB/zr8Syk2/sxDn4o3dhPgQvOFA92gAT/7mVueDISqjDenf/2xoRlHZhKt@vger.kernel.org X-Gm-Message-State: AOJu0YwQTzKBkg+bnaAhntBUZLp2qWSPguZus1H/J67GUbEUyRwm911y AFIEOvsO1e8KRX7byRmNeqRFiSodpCMaA2SDeM5oSNFmP26fX0G6KwM4vp7D0d/Z0DfiPbvB7uA vXl8PEXC/RGm7dU0TK3wRgh1edoTpzN+wHufcCr5pDCXyR+fo2Z5UTbn36mQ= X-Google-Smtp-Source: AGHT+IGS4qTWAHVh6HInzDxctIOHNPgHVf3qNkfsUrnTN2z1d47bgHqWTGEfqq1uvEbNSeBurPadRrh+/XlsvB2QIQPAgIbBMwZX Precedence: bulk X-Mailing-List: linux-hams@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:194b:b0:3dc:8b2c:4bc7 with SMTP id e9e14a558f8ab-3de38c1ba33mr104025595ab.1.1750590798918; Sun, 22 Jun 2025 04:13:18 -0700 (PDT) Date: Sun, 22 Jun 2025 04:13:18 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6857e54e.050a0220.bba34.0006.GAE@google.com> Subject: [syzbot] [hams?] possible deadlock in serial8250_console_write (2) From: syzbot To: ajk@comnets.uni-bremen.de, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 52da431bf03b Merge tag 'libnvdimm-fixes-6.16-rc3' of git:/.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1190050c580000 kernel config: https://syzkaller.appspot.com/x/.config?x=6a237c32900fc479 dashboard link: https://syzkaller.appspot.com/bug?extid=02b62f22539c818c8a0e compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/97afcc470d39/disk-52da431b.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/dc0ebacae4ba/vmlinux-52da431b.xz kernel image: https://storage.googleapis.com/syzbot-assets/85dd67feecea/bzImage-52da431b.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+02b62f22539c818c8a0e@syzkaller.appspotmail.com ===================================================== WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected 6.16.0-rc2-syzkaller-00047-g52da431bf03b #0 Not tainted ----------------------------------------------------- kworker/u8:6/3455 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: ffffffff8ece08d8 (disc_data_lock){.+.+}-{3:3}, at: sp_get drivers/net/hamradio/6pack.c:370 [inline] ffffffff8ece08d8 (disc_data_lock){.+.+}-{3:3}, at: sixpack_write_wakeup+0x30/0x480 drivers/net/hamradio/6pack.c:391 and this task is already holding: ffffffff99d96058 (&port_lock_key){-.-.}-{3:3}, at: uart_port_lock_irqsave include/linux/serial_core.h:717 [inline] ffffffff99d96058 (&port_lock_key){-.-.}-{3:3}, at: uart_port_ref_lock+0xc4/0x3b0 drivers/tty/serial/serial_core.c:83 which would create a new lock dependency: (&port_lock_key){-.-.}-{3:3} -> (disc_data_lock){.+.+}-{3:3} but this new dependency connects a HARDIRQ-irq-safe lock: (&port_lock_key){-.-.}-{3:3} ... which became HARDIRQ-irq-safe at: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:717 [inline] serial8250_console_write+0x17e/0x1ba0 drivers/tty/serial/8250/8250_port.c:3415 console_emit_next_record kernel/printk/printk.c:3138 [inline] console_flush_all+0x728/0xc40 kernel/printk/printk.c:3226 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline] console_unlock+0xc4/0x270 kernel/printk/printk.c:3325 vprintk_emit+0x5b7/0x7a0 kernel/printk/printk.c:2450 _printk+0xcf/0x120 kernel/printk/printk.c:2475 vkms_vblank_simulate+0x2be/0x320 drivers/gpu/drm/vkms/vkms_crtc.c:27 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x529/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 __outl arch/x86/include/asm/shared/io.h:24 [inline] iowrite32+0x35/0x90 lib/iomap.c:225 setup_vq+0x169/0x2e0 drivers/virtio/virtio_pci_legacy.c:150 vp_setup_vq+0xc4/0x400 drivers/virtio/virtio_pci_common.c:222 vp_find_one_vq_msix+0xc4/0x490 drivers/virtio/virtio_pci_common.c:352 vp_find_vqs_msix+0x9b0/0xd00 drivers/virtio/virtio_pci_common.c:429 vp_find_vqs+0x9c/0x760 drivers/virtio/virtio_pci_common.c:525 virtio_find_vqs include/linux/virtio_config.h:226 [inline] virtnet_find_vqs drivers/net/virtio_net.c:6435 [inline] init_vqs+0xbda/0x12d0 drivers/net/virtio_net.c:6520 virtnet_probe+0x1e35/0x4270 drivers/net/virtio_net.c:6907 virtio_dev_probe+0x914/0xbe0 drivers/virtio/virtio.c:341 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x26a/0x9a0 drivers/base/dd.c:657 __driver_probe_device+0x18c/0x2f0 drivers/base/dd.c:799 driver_probe_device+0x4f/0x430 drivers/base/dd.c:829 __driver_attach+0x452/0x700 drivers/base/dd.c:1215 bus_for_each_dev+0x230/0x2b0 drivers/base/bus.c:370 bus_add_driver+0x345/0x640 drivers/base/bus.c:678 driver_register+0x23a/0x320 drivers/base/driver.c:249 virtio_net_driver_init+0x96/0xe0 drivers/net/virtio_net.c:7211 do_one_initcall+0x233/0x820 init/main.c:1274 do_initcall_level+0x137/0x1f0 init/main.c:1336 do_initcalls+0x69/0xd0 init/main.c:1352 kernel_init_freeable+0x3d9/0x570 init/main.c:1584 kernel_init+0x1d/0x1d0 init/main.c:1474 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 to a HARDIRQ-irq-unsafe lock: (disc_data_lock){.+.+}-{3:3} ... which became HARDIRQ-irq-unsafe at: ... lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228 sp_get drivers/net/hamradio/6pack.c:370 [inline] sixpack_ioctl+0x84/0x590 drivers/net/hamradio/6pack.c:676 tty_ioctl+0x9c6/0xde0 drivers/tty/tty_io.c:2801 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(disc_data_lock); local_irq_disable(); lock(&port_lock_key); lock(disc_data_lock); lock(&port_lock_key); *** DEADLOCK *** 6 locks held by kworker/u8:6/3455: #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc9000c317bc0 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000c317bc0 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 #2: ffff888024680ca0 (&buf->lock){+.+.}-{4:4}, at: flush_to_ldisc+0x38/0x720 drivers/tty/tty_buffer.c:467 #3: ffff88807d4ea0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x90 drivers/tty/tty_ldisc.c:263 #4: ffffffff99d96058 (&port_lock_key){-.-.}-{3:3}, at: uart_port_lock_irqsave include/linux/serial_core.h:717 [inline] #4: ffffffff99d96058 (&port_lock_key){-.-.}-{3:3}, at: uart_port_ref_lock+0xc4/0x3b0 drivers/tty/serial/serial_core.c:83 #5: ffff88807d4ea0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x90 drivers/tty/tty_ldisc.c:263 the dependencies between HARDIRQ-irq-safe lock and the holding lock: -> (&port_lock_key){-.-.}-{3:3} { IN-HARDIRQ-W at: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:717 [inline] serial8250_console_write+0x17e/0x1ba0 drivers/tty/serial/8250/8250_port.c:3415 console_emit_next_record kernel/printk/printk.c:3138 [inline] console_flush_all+0x728/0xc40 kernel/printk/printk.c:3226 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline] console_unlock+0xc4/0x270 kernel/printk/printk.c:3325 vprintk_emit+0x5b7/0x7a0 kernel/printk/printk.c:2450 _printk+0xcf/0x120 kernel/printk/printk.c:2475 vkms_vblank_simulate+0x2be/0x320 drivers/gpu/drm/vkms/vkms_crtc.c:27 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x529/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 __outl arch/x86/include/asm/shared/io.h:24 [inline] iowrite32+0x35/0x90 lib/iomap.c:225 setup_vq+0x169/0x2e0 drivers/virtio/virtio_pci_legacy.c:150 vp_setup_vq+0xc4/0x400 drivers/virtio/virtio_pci_common.c:222 vp_find_one_vq_msix+0xc4/0x490 drivers/virtio/virtio_pci_common.c:352 vp_find_vqs_msix+0x9b0/0xd00 drivers/virtio/virtio_pci_common.c:429 vp_find_vqs+0x9c/0x760 drivers/virtio/virtio_pci_common.c:525 virtio_find_vqs include/linux/virtio_config.h:226 [inline] virtnet_find_vqs drivers/net/virtio_net.c:6435 [inline] init_vqs+0xbda/0x12d0 drivers/net/virtio_net.c:6520 virtnet_probe+0x1e35/0x4270 drivers/net/virtio_net.c:6907 virtio_dev_probe+0x914/0xbe0 drivers/virtio/virtio.c:341 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x26a/0x9a0 drivers/base/dd.c:657 __driver_probe_device+0x18c/0x2f0 drivers/base/dd.c:799 driver_probe_device+0x4f/0x430 drivers/base/dd.c:829 __driver_attach+0x452/0x700 drivers/base/dd.c:1215 bus_for_each_dev+0x230/0x2b0 drivers/base/bus.c:370 bus_add_driver+0x345/0x640 drivers/base/bus.c:678 driver_register+0x23a/0x320 drivers/base/driver.c:249 virtio_net_driver_init+0x96/0xe0 drivers/net/virtio_net.c:7211 do_one_initcall+0x233/0x820 init/main.c:1274 do_initcall_level+0x137/0x1f0 init/main.c:1336 do_initcalls+0x69/0xd0 init/main.c:1352 kernel_init_freeable+0x3d9/0x570 init/main.c:1584 kernel_init+0x1d/0x1d0 init/main.c:1474 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 IN-SOFTIRQ-W at: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:717 [inline] serial8250_handle_irq+0x6b/0xbb0 drivers/tty/serial/8250/8250_port.c:1917 serial8250_default_handle_irq+0xbf/0x1b0 drivers/tty/serial/8250/8250_port.c:1966 serial8250_interrupt+0xa5/0x1d0 drivers/tty/serial/8250/8250_core.c:86 __handle_irq_event_percpu+0x28c/0x980 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x267/0x9c0 kernel/irq/chip.c:789 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline] handle_irq arch/x86/kernel/irq.c:254 [inline] call_irq_handler arch/x86/kernel/irq.c:266 [inline] __common_interrupt+0x143/0x250 arch/x86/kernel/irq.c:292 common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:285 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 memset_orig+0x75/0xb0 arch/x86/lib/memset_64.S:91 unwind_next_frame+0xc98/0x2390 arch/x86/kernel/unwind_orc.c:592 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2381 [inline] slab_free mm/slub.c:4643 [inline] kfree+0x18e/0x440 mm/slub.c:4842 slab_free_after_rcu_debug+0x60/0x2a0 mm/slub.c:4680 rcu_do_batch kernel/rcu/tree.c:2576 [inline] rcu_core+0xca8/0x1710 kernel/rcu/tree.c:2832 handle_softirqs+0x286/0x870 kernel/softirq.c:579 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:968 smpboot_thread_fn+0x53f/0xa60 kernel/smpboot.c:164 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 INITIAL USE at: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:717 [inline] serial8250_do_set_termios+0x4bb/0x1c20 drivers/tty/serial/8250/8250_port.c:2774 uart_set_options+0x3c2/0x5b0 drivers/tty/serial/serial_core.c:2309 serial8250_console_setup+0x2f4/0x3c0 drivers/tty/serial/8250/8250_port.c:3519 univ8250_console_setup+0x43a/0x540 drivers/tty/serial/8250/8250_core.c:428 console_call_setup kernel/printk/printk.c:3799 [inline] try_enable_preferred_console+0x4e4/0x650 kernel/printk/printk.c:3843 register_console+0x551/0xf90 kernel/printk/printk.c:4037 univ8250_console_init+0x52/0x90 drivers/tty/serial/8250/8250_core.c:513 console_init+0x1a1/0x670 kernel/printk/printk.c:4323 start_kernel+0x2cc/0x500 init/main.c:1036 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:307 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:288 common_startup_64+0x13e/0x147 } ... key at: [] port_lock_key+0x0/0x20 the dependencies between the lock to be acquired and HARDIRQ-irq-unsafe lock: -> (disc_data_lock){.+.+}-{3:3} { HARDIRQ-ON-R at: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228 sp_get drivers/net/hamradio/6pack.c:370 [inline] sixpack_ioctl+0x84/0x590 drivers/net/hamradio/6pack.c:676 tty_ioctl+0x9c6/0xde0 drivers/tty/tty_io.c:2801 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f SOFTIRQ-ON-R at: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228 sp_get drivers/net/hamradio/6pack.c:370 [inline] sixpack_ioctl+0x84/0x590 drivers/net/hamradio/6pack.c:676 tty_ioctl+0x9c6/0xde0 drivers/tty/tty_io.c:2801 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f INITIAL USE at: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 __raw_write_lock_irq include/linux/rwlock_api_smp.h:195 [inline] _raw_write_lock_irq+0xa2/0xf0 kernel/locking/spinlock.c:326 sixpack_close+0x2c/0x280 drivers/net/hamradio/6pack.c:641 tty_ldisc_kill+0xa3/0x1a0 drivers/tty/tty_ldisc.c:613 tty_ldisc_release+0x174/0x200 drivers/tty/tty_ldisc.c:781 tty_release_struct+0x2a/0xd0 drivers/tty/tty_io.c:1681 tty_release+0xcb0/0x1640 drivers/tty/tty_io.c:1852 __fput+0x449/0xa70 fs/file_table.c:465 task_work_run+0x1d1/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:114 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline] do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f INITIAL READ USE at: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228 sp_get drivers/net/hamradio/6pack.c:370 [inline] sixpack_ioctl+0x84/0x590 drivers/net/hamradio/6pack.c:676 tty_ioctl+0x9c6/0xde0 drivers/tty/tty_io.c:2801 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f } ... key at: [] disc_data_lock+0x18/0x100 6pack.c:-1 ... acquired at: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228 sp_get drivers/net/hamradio/6pack.c:370 [inline] sixpack_write_wakeup+0x30/0x480 drivers/net/hamradio/6pack.c:391 tty_wakeup+0xbb/0x100 drivers/tty/tty_io.c:515 tty_port_default_wakeup+0xa2/0xf0 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x72e/0x970 drivers/tty/serial/8250/8250_port.c:1838 __start_tx+0x33b/0x480 drivers/tty/serial/8250/8250_port.c:1543 __uart_start+0x23c/0x440 drivers/tty/serial/serial_core.c:161 uart_write+0xdc/0x130 drivers/tty/serial/serial_core.c:636 decode_prio_command drivers/net/hamradio/6pack.c:868 [inline] sixpack_decode drivers/net/hamradio/6pack.c:943 [inline] sixpack_receive_buf+0x447/0x1450 drivers/net/hamradio/6pack.c:447 tty_ldisc_receive_buf+0x116/0x160 drivers/tty/tty_buffer.c:391 tty_port_default_receive_buf+0x6e/0xa0 drivers/tty/tty_port.c:37 receive_buf drivers/tty/tty_buffer.c:445 [inline] flush_to_ldisc+0x24a/0x720 drivers/tty/tty_buffer.c:495 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 stack backtrace: CPU: 0 UID: 0 PID: 3455 Comm: kworker/u8:6 Not tainted 6.16.0-rc2-syzkaller-00047-g52da431bf03b #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events_unbound flush_to_ldisc Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_bad_irq_dependency kernel/locking/lockdep.c:2619 [inline] check_irq_usage kernel/locking/lockdep.c:2860 [inline] check_prev_add kernel/locking/lockdep.c:3172 [inline] check_prevs_add kernel/locking/lockdep.c:3287 [inline] validate_chain+0x1f05/0x2140 kernel/locking/lockdep.c:3911 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228 sp_get drivers/net/hamradio/6pack.c:370 [inline] sixpack_write_wakeup+0x30/0x480 drivers/net/hamradio/6pack.c:391 tty_wakeup+0xbb/0x100 drivers/tty/tty_io.c:515 tty_port_default_wakeup+0xa2/0xf0 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x72e/0x970 drivers/tty/serial/8250/8250_port.c:1838 __start_tx+0x33b/0x480 drivers/tty/serial/8250/8250_port.c:1543 __uart_start+0x23c/0x440 drivers/tty/serial/serial_core.c:161 uart_write+0xdc/0x130 drivers/tty/serial/serial_core.c:636 decode_prio_command drivers/net/hamradio/6pack.c:868 [inline] sixpack_decode drivers/net/hamradio/6pack.c:943 [inline] sixpack_receive_buf+0x447/0x1450 drivers/net/hamradio/6pack.c:447 tty_ldisc_receive_buf+0x116/0x160 drivers/tty/tty_buffer.c:391 tty_port_default_receive_buf+0x6e/0xa0 drivers/tty/tty_port.c:37 receive_buf drivers/tty/tty_buffer.c:445 [inline] flush_to_ldisc+0x24a/0x720 drivers/tty/tty_buffer.c:495 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 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 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