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 90F5B334C33 for ; Wed, 1 Apr 2026 02:50:27 +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=1775011836; cv=none; b=CyGmNVOsoMltwelp3P9m6bdi9lChVYQtCTQtjdRTytyu+pUqZu+rhDEVkgEqSnEyO89xiE0AdvOM4s/6PGpQgg4BeYry88e3/rK0rJFG3w1sHqR9nQ90EFupFMMhvNKZ3JxclCuWBPQOnMjfVJWm7GpllyB1LgsE19Y91Ivg8Do= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775011836; c=relaxed/simple; bh=d9XvbMpZMXsr5WuyC8py5aQskAdWjW8sRlYYjCmr0oE=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=blm9ZanwfII6nJ0u55l0fkJrOJkIS14dEWrGs/Pn5ZllbJ4OaGbpGKWgA8q3k9NEL9UhpWzqkx/lyFDcATPnccAIzmgs/MnyWlYsogoVp9msSkjXa4XpqPwpXbksP6XAJkETbBaktNLOmY/zxDg6cFLU80zqEDiFXkXd1cHKH8M= 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 006d021491bc7-67e0d20af55so13822662eaf.2 for ; Tue, 31 Mar 2026 19:50:27 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775011825; x=1775616625; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=2UlQ8q0G556gJ98oihFFGOlpIfop0IQ16E/lf62l3L4=; b=N0VovO0/qzE7k7ywOpuLpwxzVfqSl94hmVxbgPq+90VoVqo/j97fe0E6ItEBcQCcqK xUxod8rcIEFpkxFrlC+tcdKh2v5WAmZU2YPyvfgnb94Eiq2wzd6AXe31nqGM8d27jfpA 67zOGxBqFA1DHgrg0dNf669+6UbjzZFGXAig0DkXIJYuIofK54PZ8wlxNZ7M8Lg5TbT/ 5u88fqL5QZGWb+0r7JJwSFRqvH6lICK4UGsKXrb46R5AOCXnNNxaoywdGgdA5SDTjzwq aLuH7+dQf4K8zgO3DqlP772lDZE0L1DIJvRGYo1ogq+m98Ndr28PYIBganmodTbRXXyf JgBw== X-Forwarded-Encrypted: i=1; AJvYcCXysdMS0NvKEC9h/UtPwXYApZ1lnBUA/jeYlsvRYkFz4H+UBo3etYab2TDLOW5bnHtFeNViPjg=@vger.kernel.org X-Gm-Message-State: AOJu0YwNOXwYiF44CqmYXJ3/nby9L65t5e6zV8FQcQ/3bEELr/o7Z6ZY RKPbGW0Hz1pro0N0udiLx3A30iUnTlrNnTRB8yYdPVIEsZUXVsHeMQY0SARz4qF9ARfderIcAbF Bxz6bNQqni7OiKggZqNtcvJlbTY1tZvGbDV0c9TAYF7Ej4PaUlxTmd+Q7azQ= Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:209:b0:67b:d91e:55 with SMTP id 006d021491bc7-67fabbdb6edmr954163eaf.7.1775011825255; Tue, 31 Mar 2026 19:50:25 -0700 (PDT) Date: Tue, 31 Mar 2026 19:50:25 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69cc87f1.050a0220.183828.0038.GAE@google.com> Subject: [syzbot] [net?] WARNING: refcount bug in dev_deactivate_many 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 Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: f242ac4a0944 Merge tag 'x86-urgent-2026-03-29' of git://gi.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=165f90f2580000 kernel config: https://syzkaller.appspot.com/x/.config?x=5a3e5e8c17cc174e dashboard link: https://syzkaller.appspot.com/bug?extid=1bd67523d909320dd9e2 compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/a3583806d09a/disk-f242ac4a.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/0718400bb1a9/vmlinux-f242ac4a.xz kernel image: https://storage.googleapis.com/syzbot-assets/b22f3be2e373/bzImage-f242ac4a.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+1bd67523d909320dd9e2@syzkaller.appspotmail.com ------------[ cut here ]------------ refcount_t: decrement hit 0; leaking memory. WARNING: lib/refcount.c:31 at refcount_warn_saturate+0x7c/0x130 lib/refcount.c:31, CPU#0: kworker/u8:5/93 Modules linked in: CPU: 0 UID: 0 PID: 93 Comm: kworker/u8:5 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Workqueue: events_unbound linkwatch_event RIP: 0010:refcount_warn_saturate+0x7c/0x130 lib/refcount.c:31 Code: c0 51 1a 8c e8 25 17 12 fd 83 fd 02 0f 84 a1 00 00 00 76 27 83 fd 03 74 7d 83 fd 04 75 3e e8 fb 1b 12 fd 48 8d 3d b4 57 ed 0b <67> 48 0f b9 3a e8 ea 1b 12 fd 5b 5d c3 cc cc cc cc 85 ed 74 3a e8 RSP: 0018:ffffc9000215f878 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff88802a98c664 RCX: ffffffff84f6dbcb RDX: ffff88801e7924c0 RSI: ffffffff84f6dbe5 RDI: ffffffff90e433a0 RBP: 0000000000000004 R08: 0000000000000005 R09: 0000000000000004 R10: 0000000000000004 R11: 0000000000000000 R12: 1ffff9200042bf14 R13: ffff88802a98c664 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88812433c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2ff15ff8 CR3: 000000003954a000 CR4: 00000000003526f0 Call Trace: __refcount_dec include/linux/refcount.h:461 [inline] refcount_dec include/linux/refcount.h:476 [inline] ref_tracker_free+0x5cd/0x6c0 lib/ref_tracker.c:303 netdev_tracker_free include/linux/netdevice.h:4456 [inline] netdev_put include/linux/netdevice.h:4473 [inline] netdev_put include/linux/netdevice.h:4469 [inline] netdev_watchdog_down net/sched/sch_generic.c:575 [inline] dev_deactivate_many+0x28f/0xfc0 net/sched/sch_generic.c:1337 dev_deactivate+0xf8/0x1c0 net/sched/sch_generic.c:1368 linkwatch_do_dev net/core/link_watch.c:184 [inline] linkwatch_do_dev+0xce/0x110 net/core/link_watch.c:166 __linkwatch_run_queue+0x3a9/0x900 net/core/link_watch.c:240 linkwatch_event+0x8f/0xc0 net/core/link_watch.c:314 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276 process_scheduled_works kernel/workqueue.c:3359 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 ---------------- Code disassembly (best guess): 0: c0 51 1a 8c rclb $0x8c,0x1a(%rcx) 4: e8 25 17 12 fd call 0xfd12172e 9: 83 fd 02 cmp $0x2,%ebp c: 0f 84 a1 00 00 00 je 0xb3 12: 76 27 jbe 0x3b 14: 83 fd 03 cmp $0x3,%ebp 17: 74 7d je 0x96 19: 83 fd 04 cmp $0x4,%ebp 1c: 75 3e jne 0x5c 1e: e8 fb 1b 12 fd call 0xfd121c1e 23: 48 8d 3d b4 57 ed 0b lea 0xbed57b4(%rip),%rdi # 0xbed57de * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: e8 ea 1b 12 fd call 0xfd121c1e 34: 5b pop %rbx 35: 5d pop %rbp 36: c3 ret 37: cc int3 38: cc int3 39: cc int3 3a: cc int3 3b: 85 ed test %ebp,%ebp 3d: 74 3a je 0x79 3f: e8 .byte 0xe8 --- 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