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 29EB239A7F2 for ; Thu, 13 Aug 2026 08:59:31 +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=1786611574; cv=none; b=Pm/vgtnDNL0tobeqM1ugOt+JunHX8SVMMrAS5lDkIX8GEG3EY1F/vJ0CvUUHJttYLGI6su0GQdcdHO8tsaeKUZhILb9L8YhHu8xGRhzUeCisujrJsLp+VXwG/HknH8BoQnZNnRNAPxuyy3lrplJQp2ceKpT9gsm288RjCTjpUAc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786611574; c=relaxed/simple; bh=isw7UPUMWbVsmqLjO8nrNnypyaJxT9erAkEpWTf83rQ=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=JytTiN25qZXid4dfjxvuj3G7EdrwekEo0X6t3y9Q8EYGk5uWTPSUja2mPmuV9o9xHQ+pI8h1t0W7EOtfedBDOgafzjxJfCLW6ntvFk+Ef1RnPoYoI/fJxMJ8NOjhswcXBOe9c1ScRV20o8YJ9/EEIDe4Cw3C0jRfePcMRu3wLEg= 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 006d021491bc7-6ae35c7b9a9so162542eaf.2 for ; Thu, 13 Aug 2026 01:59:31 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786611571; x=1787216371; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=tE1+RzQhpvKQxLGpZ5xo6ecpjtwzXrqcnNj3zDdS/kU=; b=bmG04ApN50PEiaYJV2vbvlb0UeOay9JxDP3FEBb4nru/UeOFiE964epaXywY4Dn9lW jAuKkz7wGwBr1Cid0OQkHYd+memmvCg83nZYYfSiMyMuOAIYnCpmOFQfW+SJE9SCy6Jy i6R/oKVQXNYZfo0PuAh2R3TNaUM2kaN6piFrzJBRBngZC3H8JyRWDJQUhO1BetzJC7rH m8QpttMSs6ykNHViZ4A5r0OEMD3YylX8FZfIJ86U2DUjm7pH6sQyhq4KSDC65HnSVzut kfSIa4nsY98W670kSU5dlp6/GDat8Hf+i85nWSatbtx1tTtnu9hnnI2hPIJyDgtD2sfG i5Cw== X-Forwarded-Encrypted: i=1; AHgh+RqTFsYy/6pdk3S58Or1yI8slph3ii2+YNL4qXZe9bZgVj9iUToX0xGnh+ylFsYkWzgZykirVPg=@vger.kernel.org X-Gm-Message-State: AOJu0YzP6XUEusKx3cZUXB32gTaPJZGCwUR01NBBvVC4RvuNA/VKnVXw iL6CUWTKAjJXjxkMMsHwKdRdRcOHqbplT2+vrav2uLccphaf8yApbLa0pHqay31vIOf0QXAL+L5 tqi2aWAaiIYNeDBx0KmKx3xQivSCeNQ0529GX1Q2RhiZZ0yPg3qpHgTN/0gU= Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:1844:b0:6b0:19bc:fd14 with SMTP id 006d021491bc7-6b0c45ca615mr4405974eaf.32.1786611571127; Thu, 13 Aug 2026 01:59:31 -0700 (PDT) Date: Thu, 13 Aug 2026 01:59:31 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a7d8773.c5ad36c8.12f49d.002e.GAE@google.com> Subject: [syzbot] [sctp?] WARNING: refcount bug in sctp_transport_put (6) From: syzbot To: davem@davemloft.net, edumazet@google.com, horms@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org, linux-sctp@vger.kernel.org, lucien.xin@gmail.com, marcelo.leitner@gmail.com, 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: 3d6d817622b0 Merge tag 'scsi-fixes' of git://git.kernel.or.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=17b9f479580000 kernel config: https://syzkaller.appspot.com/x/.config?x=c44651ea7dd2f307 dashboard link: https://syzkaller.appspot.com/bug?extid=80dfcb1a2235b3efc877 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/025cec82d3d2/disk-3d6d8176.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/9200091a0c2f/vmlinux-3d6d8176.xz kernel image: https://storage.googleapis.com/syzbot-assets/b47828829039/bzImage-3d6d8176.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+80dfcb1a2235b3efc877@syzkaller.appspotmail.com ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: lib/refcount.c:28 at refcount_warn_saturate+0xf4/0x130 lib/refcount.c:28, CPU#1: swapper/1/0 Modules linked in: CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:refcount_warn_saturate+0xf4/0x130 lib/refcount.c:28 Code: cc e8 10 93 ec fc 48 8d 3d 09 be 0e 0c 67 48 0f b9 3a e8 ff 92 ec fc 5b 5d e9 d8 23 a0 06 e8 f3 92 ec fc 48 8d 3d fc bd 0e 0c <67> 48 0f b9 3a e8 e2 92 ec fc 5b 5d c3 cc cc cc cc e8 d6 92 ec fc RSP: 0018:ffffc90000a08c28 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff88802afce820 RCX: ffffffff851ddffb RDX: ffff88801eaca540 RSI: ffffffff851de08d RDI: ffffffff912c9e90 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000004 R10: 0000000000000003 R11: 0000000000000000 R12: ffff88802afce820 R13: 1ffff9200014118e R14: ffffffff8af14810 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888123eec000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe49ed8e10 CR3: 000000005416b000 CR4: 00000000003526f0 Call Trace: __refcount_sub_and_test include/linux/refcount.h:400 [inline] __refcount_dec_and_test include/linux/refcount.h:432 [inline] refcount_dec_and_test include/linux/refcount.h:450 [inline] sctp_transport_put+0x134/0x180 net/sctp/transport.c:476 call_timer_fn+0x19a/0x610 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers+0x757/0xb00 kernel/time/timer.c:2374 __run_timer_base kernel/time/timer.c:2386 [inline] __run_timer_base kernel/time/timer.c:2378 [inline] run_timer_base+0x114/0x190 kernel/time/timer.c:2395 run_timer_softirq+0x1a/0x50 kernel/time/timer.c:2405 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64 Code: 55 8c 02 e9 83 4b 03 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 83 cf 10 00 fb f4 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197e00 EFLAGS: 00000246 RAX: 0000000002ec63ed RBX: ffff88801eaca540 RCX: ffffffff8bbad335 RDX: 0000000000000000 RSI: ffffffff8e1a9419 RDI: ffffffff8c400480 RBP: ffffed1003d594a8 R08: 0000000000000001 R09: ffffed10170a678d R10: ffff8880b8533c6b R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 1ffff92000032fc4 R15: dffffc0000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline] default_idle+0x9/0x10 arch/x86/kernel/process.c:768 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x3a7/0x5b0 kernel/sched/idle.c:355 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:454 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x158 ---------------- Code disassembly (best guess): 0: cc int3 1: e8 10 93 ec fc call 0xfcec9316 6: 48 8d 3d 09 be 0e 0c lea 0xc0ebe09(%rip),%rdi # 0xc0ebe16 d: 67 48 0f b9 3a ud1 (%edx),%rdi 12: e8 ff 92 ec fc call 0xfcec9316 17: 5b pop %rbx 18: 5d pop %rbp 19: e9 d8 23 a0 06 jmp 0x6a023f6 1e: e8 f3 92 ec fc call 0xfcec9316 23: 48 8d 3d fc bd 0e 0c lea 0xc0ebdfc(%rip),%rdi # 0xc0ebe26 * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: e8 e2 92 ec fc call 0xfcec9316 34: 5b pop %rbx 35: 5d pop %rbp 36: c3 ret 37: cc int3 38: cc int3 39: cc int3 3a: cc int3 3b: e8 d6 92 ec fc call 0xfcec9316 --- 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