From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-io1-f80.google.com (mail-io1-f80.google.com [209.85.166.80]) (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 CED3B2D5C6C for ; Thu, 13 Nov 2025 10:35:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763030129; cv=none; b=B5g4rl48pN1oeV6Y/QInSGILTmthvXDwkjQK7qwWwDLJYzr08M2NAbUDK/io9jNu0lwPqK0lq/odtZVszCYCQfW6TespNHDb0idjvJdKfhF1M70Up+EZ7f+vuiF+yRUrUc2vJrBikulDk3bGAGgBkqtqCOQyrkeyAtJOsL8/yrw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763030129; c=relaxed/simple; bh=IgQgjGtFBP7AF+NZw7x3LDmSXHsIm8i+o+6jOICboEU=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=AJIvFgec8Fn3eyIUQFxLQWkLoxo1xyIKLWGKHItlT77lKU0929op64vh2ydiNJqlJ6QcZLimNqI7kuEZH4OgdFSJhSR10jOX0r6EhKpoGWOxBMlgp3SeD4ciZ6JFXXpaE0MDm6MiILSUoOl8gjxp3ZrxCwHIdu6wndBUlwkD/b4= 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=209.85.166.80 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-io1-f80.google.com with SMTP id ca18e2360f4ac-9489c73d908so66176139f.2 for ; Thu, 13 Nov 2025 02:35:27 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763030127; x=1763634927; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=FbdEWJA56FdSIhplP5wNxS54najxWArCAOLlDXVaQYE=; b=mJdS7v0/OXYXOMj4qPP+Gxy7nxRQfbjLzLWKECKltuWOcfdDH/CI6nDYW1mNE4/HK4 BWTW4sC7ibBbTxsRB/YYqIWx4eOBOEHkChvWUFAh72lZ9JhXqeLN8R675nDcjrfBxc8L Sbw9twXJyjNfhf4hng7khUq5p7RmcqjGahyAkIXdOHxos+il10svMOn0cjCYAJAMV0Nb YMHFN/Ga5ajRoIp9q+4+ugU0wbWfcB1Fx2CgTYxpgpMglL8uqU+n65zDSrTFabpY36VQ xFr4iFRbop7LKgpKQMr9Sifjc3kO2kkYTShSuCdnvQf7pbETcnKSYeSWM9ayofkmrC85 7f+w== X-Forwarded-Encrypted: i=1; AJvYcCU/ZLYr+0OswIO3a7m+vpJIpopXqoBaQypnUJUVlSI64Qyc/m2tayhEiwfYmobd9SAZ7+oWGQwZ0G9QcH8=@vger.kernel.org X-Gm-Message-State: AOJu0YzJJoM65TMBy6Vg/flr/MjaIMZ/6M3DmmUCnQ/zj9hUWQaZQOzZ NZ6Rm010hv3VGO02023i4LFfiTeZMN83bPLRV+XHV2QQF7ohp4SjlX+0ylhQpxnUutIFvrLio1l cvYeljD4sN33WAuOeRrQgsM/FLV7tflG49GIXI2IFDPdaFISXuulnvbkX+i4= X-Google-Smtp-Source: AGHT+IHIMygvJ0QGQ9pVbXAgtD7mvDrcbNhKzdQ0GRQ2mpHNwLxpAeEclC0oGseOQWc80tJQtPOdoaXHj15IlmGI2ADMJxFqQqhq Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:2194:b0:433:7673:1d with SMTP id e9e14a558f8ab-43473db48a9mr75823835ab.31.1763030127042; Thu, 13 Nov 2025 02:35:27 -0800 (PST) Date: Thu, 13 Nov 2025 02:35:27 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6915b46f.050a0220.3565dc.0028.GAE@google.com> Subject: [syzbot] [mptcp?] WARNING: refcount bug in mptcp_schedule_work (2) From: syzbot To: davem@davemloft.net, edumazet@google.com, geliang@kernel.org, horms@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org, martineau@kernel.org, matttbe@kernel.org, mptcp@lists.linux.dev, 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: 24172e0d7990 Merge tag 'arm64-fixes' of git://git.kernel.o.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=11da1c12580000 kernel config: https://syzkaller.appspot.com/x/.config?x=41ad820f608cb833 dashboard link: https://syzkaller.appspot.com/bug?extid=355158e7e301548a1424 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/38a395e6659a/disk-24172e0d.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/23093acc54e6/vmlinux-24172e0d.xz kernel image: https://storage.googleapis.com/syzbot-assets/ef12edc574bd/bzImage-24172e0d.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+355158e7e301548a1424@syzkaller.appspotmail.com ------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 0 PID: 16 at lib/refcount.c:25 refcount_warn_saturate+0xfa/0x1d0 lib/refcount.c:25 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:refcount_warn_saturate+0xfa/0x1d0 lib/refcount.c:25 Code: 00 00 e8 79 5a 45 fd 5b 41 5e c3 cc cc cc cc cc e8 6b 5a 45 fd c6 05 3f 24 47 0a 01 90 48 c7 c7 80 2e 3d 8b e8 57 a1 09 fd 90 <0f> 0b 90 90 eb d7 e8 4b 5a 45 fd c6 05 20 24 47 0a 01 90 48 c7 c7 RSP: 0018:ffffc90000157830 EFLAGS: 00010246 RAX: 8853f029dd577500 RBX: 0000000000000002 RCX: ffff88801b2dda00 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000100 R10: dffffc0000000000 R11: ffffed101710487b R12: 1ffff9200002af18 R13: ffff88805cbc5e60 R14: ffff88805cbc5a80 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888126df7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2ee13ff8 CR3: 0000000056192000 CR4: 00000000003526f0 Call Trace: __refcount_add include/linux/refcount.h:-1 [inline] __refcount_inc include/linux/refcount.h:366 [inline] refcount_inc include/linux/refcount.h:383 [inline] sock_hold include/net/sock.h:816 [inline] mptcp_schedule_work+0x164/0x1a0 net/mptcp/protocol.c:943 mptcp_tout_timer+0x21/0xa0 net/mptcp/protocol.c:2316 call_timer_fn+0x17e/0x5f0 kernel/time/timer.c:1747 expire_timers kernel/time/timer.c:1798 [inline] __run_timers kernel/time/timer.c:2372 [inline] __run_timer_base+0x648/0x970 kernel/time/timer.c:2384 run_timer_base kernel/time/timer.c:2393 [inline] run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403 handle_softirqs+0x22f/0x710 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] run_ktimerd+0xcf/0x190 kernel/softirq.c:1138 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 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 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