From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oa1-f80.google.com (mail-oa1-f80.google.com [209.85.160.80]) (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 840E32222A0 for ; Mon, 29 Dec 2025 14:09:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767017375; cv=none; b=greYXsACU3gh2rL9+pDtVSVIqcoKoeIGy7rymAkjrlFzghUMluHBbr6PBOsfrnnqIMMpc4dGaC7rOfcCU0y/C/t7ctDyYXxoxEaYHi7fd0kcu/oBQd6zhkxYFl1ITPeCTst6JJgbDgmkEOfRyJXaDffWMcegosRYvlAgd/dWnfk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767017375; c=relaxed/simple; bh=JBmddtQ2wW9rHVi/KTtehcF8xeLzKpXc6MJk6zJGoNc=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=U9hTv6I7Pi8VlTTkKiFviSRi0fSj6Ed3u0E3u0M/TxCCabbQvLI+pe507v6eGDrOyldrjT5An1UaJpjnEH7ZhrWurRivkiCbnm3w3IwRlkYuVly53NCiqgkFWnN1zKwFjYFC11NU6c6yo+HEK+7X8dF+L7n3bToH8QloN/+LK+k= 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=209.85.160.80 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-oa1-f80.google.com with SMTP id 586e51a60fabf-3f0cc00376dso15223910fac.0 for ; Mon, 29 Dec 2025 06:09:32 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767017371; x=1767622171; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=VOvCZFX94Wy/FQexBTyZeQINiOCGQDsX01AhIlUm7WM=; b=C70/h/ngfOGbAbqRnWwR68wIy5eNqXFSDQZ7zeVfXG6RGGK/XHxersWhtZaMPY6Pri HKdi5KWxrX0dlkGmOrAZsPoG8XcfKiDaKfAVJnDhH6ovRi9azHGIQRqUhKJ8fJgCkXOS 3eZOo4/TKaROtUI9WBc5ZRaLOYijzQgsvCb5sFGryg1hAL97IWeIDlHcwWrvenKvVUha rul1yo8nYnpRttj7U1Lkb7Ku3C30F0EqxHI9zy+ob6Jo5F6gpJfE42VEUSmzO4bv1l4b jnnW0LN5Eraq2XQkOMg76tYgRlRJBKwrV1G4naWhpYMDdYwf9odFNsrYvg826stl7/JY 2qGw== X-Forwarded-Encrypted: i=1; AJvYcCWWve+FbRaGYWPQznS4e40FXIqw9wUk0L82up14u772tcKL0lFpuleBgj9L2wU2SVi+BoRXsUvrJnR0WPE=@vger.kernel.org X-Gm-Message-State: AOJu0YyScFKf3g2QrJAvJImWyGqbiAdJEKbZ9Eol3KGRIZX6L+AjRgpo OcsRt1TZN44DS08NelCId+TZA5wxpQcIirBLesSxwz+lkz5SRwl661UR064Y/+IDE/T1z8NjfhD UTTpdqCraeQOKvs64MoBMYzHxyJzZLLXQ+2OyGc9LHMjOc3uA7fgm+Wa667E= X-Google-Smtp-Source: AGHT+IG8c6vO6aSbBMs19NszwBQCcgEzkEnKa0ihuu0Q+ReS2NWvK5EiAJ8rFROMVI4xZurVy/VnabguV9R5gVKwauEbE45f4OX8 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:2212:b0:659:9a49:9046 with SMTP id 006d021491bc7-65d0e94d381mr13611673eaf.17.1767017371516; Mon, 29 Dec 2025 06:09:31 -0800 (PST) Date: Mon, 29 Dec 2025 06:09:31 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69528b9b.050a0220.329c0f.0417.GAE@google.com> Subject: [syzbot] [net?] WARNING: locking bug in finish_task_switch (2) From: syzbot To: davem@davemloft.net, edumazet@google.com, horms@kernel.org, jhs@mojatatu.com, jiri@resnulli.us, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, syzkaller-bugs@googlegroups.com, xiyou.wangcong@gmail.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: ccd1cdca5cd4 Merge tag 'nfsd-6.19-1' of git://git.kernel.o.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1417109a580000 kernel config: https://syzkaller.appspot.com/x/.config?x=1f2b6fe1fdf1a00b dashboard link: https://syzkaller.appspot.com/bug?extid=fa2e2b8fd1b3f689d484 compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/7a2605cdbf37/disk-ccd1cdca.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/1a90296b9771/vmlinux-ccd1cdca.xz kernel image: https://storage.googleapis.com/syzbot-assets/01272b1902ce/bzImage-ccd1cdca.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+fa2e2b8fd1b3f689d484@syzkaller.appspotmail.com ------------[ cut here ]------------ DEBUG_LOCKS_WARN_ON(1) WARNING: kernel/locking/lockdep.c:238 at hlock_class kernel/locking/lockdep.c:238 [inline], CPU#0: ktimers/0/16 WARNING: kernel/locking/lockdep.c:238 at check_wait_context kernel/locking/lockdep.c:4879 [inline], CPU#0: ktimers/0/16 WARNING: kernel/locking/lockdep.c:238 at __lock_acquire+0x55a/0x2cf0 kernel/locking/lockdep.c:5187, CPU#0: ktimers/0/16 Modules linked in: CPU: 0 UID: 0 PID: 16 Comm: ktimers/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:hlock_class kernel/locking/lockdep.c:238 [inline] RIP: 0010:check_wait_context kernel/locking/lockdep.c:4879 [inline] RIP: 0010:__lock_acquire+0x561/0x2cf0 kernel/locking/lockdep.c:5187 Code: 83 3d a2 bd 21 17 00 75 27 90 e8 ba 99 dd 02 85 c0 74 1c 83 3d c3 bd 3e 0d 00 75 13 48 8d 3d d6 c1 41 0d 48 c7 c6 ca 31 ee 8c <67> 48 0f b9 3a 90 31 c9 0f b6 81 c4 00 00 00 84 c0 0f 84 77 ff ff RSP: 0018:ffffc900001571b0 EFLAGS: 00010046 RAX: 0000000000000001 RBX: ffff88801b6de760 RCX: ffff88801b6ddac0 RDX: 0000000000000100 RSI: ffffffff8cee31ca RDI: ffffffff8ede4890 RBP: ffff88801b6de768 R08: 0000000000000000 R09: 0000000000000100 R10: dffffc0000000000 R11: fffffbfff1db688f R12: 0000000000000003 R13: ffff88801b6de768 R14: ffff88801b6ddac0 R15: 0000000000000006 FS: 0000000000000000(0000) GS:ffff888126cef000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2f617ff8 CR3: 0000000033f24000 CR4: 00000000003526f0 Call Trace: lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 finish_lock_switch kernel/sched/core.c:4993 [inline] finish_task_switch+0x177/0x940 kernel/sched/core.c:5112 context_switch kernel/sched/core.c:5259 [inline] __schedule+0x1467/0x5070 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule_rtlock+0x30/0x70 kernel/sched/core.c:7024 rtlock_slowlock_locked+0x3819/0x4010 kernel/locking/rtmutex.c:1868 rtlock_slowlock kernel/locking/rtmutex.c:1895 [inline] rtlock_lock kernel/locking/spinlock_rt.c:43 [inline] __rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline] rt_spin_lock+0x158/0x3e0 kernel/locking/spinlock_rt.c:57 spin_lock include/linux/spinlock_rt.h:44 [inline] fq_pie_timer+0x190/0x5b0 net/sched/sch_fq_pie.c:397 call_timer_fn+0x16e/0x590 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers kernel/time/timer.c:2373 [inline] __run_timer_base+0x648/0x970 kernel/time/timer.c:2385 run_timer_base kernel/time/timer.c:2394 [inline] run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2404 handle_softirqs+0x1df/0x650 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] run_ktimerd+0x69/0x100 kernel/softirq.c:1138 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 ---------------- Code disassembly (best guess): 0: 83 3d a2 bd 21 17 00 cmpl $0x0,0x1721bda2(%rip) # 0x1721bda9 7: 75 27 jne 0x30 9: 90 nop a: e8 ba 99 dd 02 call 0x2dd99c9 f: 85 c0 test %eax,%eax 11: 74 1c je 0x2f 13: 83 3d c3 bd 3e 0d 00 cmpl $0x0,0xd3ebdc3(%rip) # 0xd3ebddd 1a: 75 13 jne 0x2f 1c: 48 8d 3d d6 c1 41 0d lea 0xd41c1d6(%rip),%rdi # 0xd41c1f9 23: 48 c7 c6 ca 31 ee 8c mov $0xffffffff8cee31ca,%rsi * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: 90 nop 30: 31 c9 xor %ecx,%ecx 32: 0f b6 81 c4 00 00 00 movzbl 0xc4(%rcx),%eax 39: 84 c0 test %al,%al 3b: 0f .byte 0xf 3c: 84 77 ff test %dh,-0x1(%rdi) 3f: ff .byte 0xff --- 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