From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f77.google.com (mail-ot1-f77.google.com [209.85.210.77]) (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 5CBD53264F7 for ; Mon, 22 Jun 2026 17:01:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.77 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782147688; cv=none; b=kljmzEEay2hGNJkf5b7J3KMqIwDYNKcXrgMeOLHuqOUdXmU405Xot0JU2aYEg8rjA9fsodETTe9mUAhlTm6XL9lm5aSyF3bLbHqlyq4i9NuUaD7qX6cAScINuogRM5nst6M+xq5dsXlbs2nMPzugykTYaimHsnzewUaalvSljbY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782147688; c=relaxed/simple; bh=d7IfLOXULxFfoxCxZL6h1WiDjlcreZF/0pv22enkCVc=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=eswckEyUkkgceW9OhqELf5huNlBjYMnB7PLpxtUSrAt6bDBdxNG+pdpOCpKXob27dMVDNSPd2uM6oxOOcZERvqFN3RMvVpCbHAmrR/u1AUF5ezOprzLN1vriFF28KdRcJKpjD6P9zSDwurgxm2P63hjrsSazdIR1eg1iR3WoRJ4= 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=209.85.210.77 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-ot1-f77.google.com with SMTP id 46e09a7af769-7e757d8937aso8729880a34.2 for ; Mon, 22 Jun 2026 10:01:27 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782147686; x=1782752486; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=grJrt3G4vW1MLNQdhPY5UoHK94iiFCg4Mi4xoetGlHI=; b=NlS9fttiiwjuFWnUbDsePxLHp+13gvhUEASwI0chk0SbyXHR1TwYHHgDv+o6EOPl+f buyIaj2E3sI3ten/ajRZX0GvfI6Ez+dR14mTdzc/oUUqFIAKxwKMscO/+Mb1SMWBeKmO 2NcJRrhvRJv8Am3dKqbTyxwsm40x93QcYbZov2XaTDSPXr/MDOfcMx6f1GBNnDyZWX+g dmRJdKlwS5sr4f3DwsD5Jiq58ku+Y1z5HJYuYT864cOCrmbeLXzESIEd+jO9L+UeIZzH +4xXLsQWwPInaxYC/GpNS+bm4sasud6t4PbWgAV2T1c8W75sXsjjFS7yD2iLR/+Dbyvz Fs5A== X-Forwarded-Encrypted: i=1; AFNElJ+RWYwpuMFiobYvm8EuWha7JMFgEv39NR/HwskoQ1OBVqhXr5+CB6uh7+jPbXA7wsvdSoRE9mQ=@vger.kernel.org X-Gm-Message-State: AOJu0Yz50jmZqySjOCAwfeUD03AK+hlrhIvpDbuT8ocCqhXoFySb7ySm DSNv8bU1fKRqdtpzw7XTKRrm9UJgFF/MrRJjlNE14hGjQZEZDmaS8NlptI9oqjCO5FO/GgviBiE QrfBtFyDKJSci7niBlqLQqX3Ug3Gr77fjAEEaTYKj6frEx8fG0h9Dhv0BV3U= Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6830:4115:b0:7e6:f7fb:9678 with SMTP id 46e09a7af769-7e931d5eab6mr13671236a34.1.1782147686360; Mon, 22 Jun 2026 10:01:26 -0700 (PDT) Date: Mon, 22 Jun 2026 10:01:26 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a396a66.52ae72c2.136ac7.0003.GAE@google.com> Subject: [syzbot] [net?] WARNING in rcuref_put_slowpath From: syzbot To: davem@davemloft.net, edumazet@google.com, horms@kernel.org, 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: 4fa3f5fabb30 Add linux-next specific files for 20260616 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=1427abd2580000 kernel config: https://syzkaller.appspot.com/x/.config?x=6c414e1864e61ef6 dashboard link: https://syzkaller.appspot.com/bug?extid=e14bc5d4942756023b77 compiler: Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/bf5b803a695d/disk-4fa3f5fa.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/47871e7c589e/vmlinux-4fa3f5fa.xz kernel image: https://storage.googleapis.com/syzbot-assets/53cd9ef32a2b/bzImage-4fa3f5fa.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+e14bc5d4942756023b77@syzkaller.appspotmail.com ------------[ cut here ]------------ rcuref - imbalanced put() WARNING: lib/rcuref.c:266 at rcuref_put_slowpath+0x16e/0x1d0 lib/rcuref.c:266, 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 05/09/2026 RIP: 0010:rcuref_put_slowpath+0x16e/0x1d0 lib/rcuref.c:266 Code: c1 e8 03 42 0f b6 04 38 84 c0 75 48 c7 03 00 00 00 a0 31 c0 e9 6d ff ff ff e8 fe 13 80 06 e8 49 d7 14 fd 48 8d 3d 62 f3 e6 0a <67> 48 0f b9 3a 48 89 df be 04 00 00 00 e8 40 b3 80 fd 48 89 d8 48 RSP: 0018:ffffc90000157560 EFLAGS: 00010246 RAX: ffffffff84b04017 RBX: ffff888025328740 RCX: ffff88801d680000 RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffffffff8f973380 RBP: ffffc900001575e8 R08: 0000000000000000 R09: 0000000000000100 R10: dffffc0000000000 R11: ffffed1004a650e9 R12: 1ffff9200002aeac R13: dffffc0000000000 R14: 00000000dfffffff R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888125ed3000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f67d5f2c558 CR3: 0000000026bb4000 CR4: 00000000003526f0 Call Trace: __rcuref_put include/linux/rcuref.h:117 [inline] rcuref_put+0x15b/0x170 include/linux/rcuref.h:173 dst_release+0x31/0x1b0 net/core/dst.c:251 dst_cache_per_cpu_get+0x25a/0x2d0 net/core/dst_cache.c:57 dst_cache_get+0x10d/0x1e0 net/core/dst_cache.c:75 tipc_udp_xmit+0xcf/0xb30 net/tipc/udp_media.c:177 tipc_bearer_xmit_skb+0x2b3/0x400 net/tipc/bearer.c:576 tipc_disc_timeout+0x642/0x790 net/tipc/discover.c:338 call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers kernel/time/timer.c:2374 [inline] __run_timer_base+0x67b/0x9b0 kernel/time/timer.c:2386 run_timer_base kernel/time/timer.c:2395 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405 handle_softirqs+0x1d9/0x6c0 kernel/softirq.c:626 __do_softirq kernel/softirq.c:660 [inline] run_ktimerd+0x69/0x100 kernel/softirq.c:1155 smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160 kthread+0x388/0x470 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 ---------------- Code disassembly (best guess): 0: c1 e8 03 shr $0x3,%eax 3: 42 0f b6 04 38 movzbl (%rax,%r15,1),%eax 8: 84 c0 test %al,%al a: 75 48 jne 0x54 c: c7 03 00 00 00 a0 movl $0xa0000000,(%rbx) 12: 31 c0 xor %eax,%eax 14: e9 6d ff ff ff jmp 0xffffff86 19: e8 fe 13 80 06 call 0x680141c 1e: e8 49 d7 14 fd call 0xfd14d76c 23: 48 8d 3d 62 f3 e6 0a lea 0xae6f362(%rip),%rdi # 0xae6f38c * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: 48 89 df mov %rbx,%rdi 32: be 04 00 00 00 mov $0x4,%esi 37: e8 40 b3 80 fd call 0xfd80b37c 3c: 48 89 d8 mov %rbx,%rax 3f: 48 rex.W --- 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