From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f80.google.com (mail-oo1-f80.google.com [209.85.161.80]) (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 C95DE34D90E for ; Mon, 16 Mar 2026 08:09:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773648574; cv=none; b=tXxgQhboJFG4a1cuDOt5cWVDLzwhPley4qHK8SfNfj2LmJh2LtkT7uZ8i1pWCW7mTT17CQXh05oFd91/3gQveYw4keVSlmDSopicqgA3CX6BxE1Wv4zZymrdMOfzWbWEBYjEoBA/u5NHoV6MFshFL+pLUP+fxk1z06V2kMO6ILs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773648574; c=relaxed/simple; bh=thJD365okiqenSnQljJAGI+XKEWMc5ZNmCVmFSVYImM=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=VsoAl6sDZyEmgNwpDk7PvSLTbL1MVRGlAp9eAH9WkkF8P5+gGfspNIUeusfyPFGKLVQXpWXbA+el0TOb5yYjGKB8+nQ9C+vg5Ms0rabl5NR2g4h3YQtTpCXvi9uTwdEOLVcioXCO++dQWZp8NoL9vxxPC0n/uKeGKiY/cBDZVag= 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=209.85.161.80 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-oo1-f80.google.com with SMTP id 006d021491bc7-67bc5678917so38153656eaf.2 for ; Mon, 16 Mar 2026 01:09:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1773648572; x=1774253372; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=DFVik9JcxFFGQ9+gVQI6AOtVrNX2GuuPZE33BKs9lmM=; b=NPjCb3AzXMXI74sIOa+heXtTrK0W/IxvGHqfcRUZmHTdOZ+E+F4lbuX31hAU8sYVtS JknngdxlBWeWmosHsLRqgwQAi1zAsoERlTlx61XDm/hbekq0uVS7Rfk7aVPS43FiUSsm Z0dh/gL3kL4gV4EwO/n58wIPpvO8uZO/7kHwHFplM6zcrMZXBfc7eWT0P4lLFX6aI7un Um5ukGX68YPCVyaeQP52rIRrV8tx1FvFRd6x9bgTUXKIAQFL9quo/QlLZKtFfV5Gyjmn ufxjbYUqoreSTJFkL6zisG4lUhzdoJ7QyfC/0cBhpLoWXhNP4ec7dS0PwEsDHEPdAT2f 9zxQ== X-Forwarded-Encrypted: i=1; AJvYcCUqdmBSWJ+OmnwhaKNGbKWySjzEs+KB65wYs4TYi+ahIrp9OlT+HQo5hLzd5dnG33p9OCmauaE=@vger.kernel.org X-Gm-Message-State: AOJu0Yy41hmysbPk+Mx1r406w5fK6jGwai52JwWoxhiTQV0i3Gg+qoKw COb75nkJgMk0ydzXJsRqVTChtqMvbrsQnuwEcBcXUv9f2Z42hkgeU5vo82WzfZV1CSJCsEkN1gO Jznkt1cN6mhBC3hFU6rAfHynEyl6sahXdQhv+uLCGZMRR+VtZozLFZMZ6MN8= Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:1895:b0:67b:b718:1a44 with SMTP id 006d021491bc7-67bda9ecb48mr8188993eaf.31.1773648571787; Mon, 16 Mar 2026 01:09:31 -0700 (PDT) Date: Mon, 16 Mar 2026 01:09:31 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69b7babb.a00a0220.3b25d1.0024.GAE@google.com> Subject: [syzbot] [net?] WARNING: refcount bug in mpoad_close 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: 17edc4e820bf net: Convert move_addr_to_user() to scoped us.. git tree: net-next console output: https://syzkaller.appspot.com/x/log.txt?x=16b0d94a580000 kernel config: https://syzkaller.appspot.com/x/.config?x=779072223d02a312 dashboard link: https://syzkaller.appspot.com/bug?extid=5ec223ccb83b24ef982f compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/8240a6a26b71/disk-17edc4e8.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/f03f846934c5/vmlinux-17edc4e8.xz kernel image: https://storage.googleapis.com/syzbot-assets/18938471b971/bzImage-17edc4e8.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+5ec223ccb83b24ef982f@syzkaller.appspotmail.com ------------[ cut here ]------------ refcount_t: decrement hit 0; leaking memory. WARNING: lib/refcount.c:31 at refcount_warn_saturate+0x70/0x110 lib/refcount.c:31, CPU#1: syz.0.7057/31630 Modules linked in: CPU: 1 UID: 0 PID: 31630 Comm: syz.0.7057 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/27/2026 RIP: 0010:refcount_warn_saturate+0x70/0x110 lib/refcount.c:31 Code: c6 00 28 f0 8e e8 10 13 17 fd 83 fb 01 7e 22 83 fb 02 74 39 83 fb 03 74 47 83 fb 04 75 68 e8 77 0d 17 fd 48 8d 3d 30 70 6d 0b <67> 48 0f b9 3a eb 66 85 db 74 3e 83 fb 01 75 4c e8 5b 0d 17 fd 48 RSP: 0018:ffffc9000cbdfb08 EFLAGS: 00010293 RAX: ffffffff84ae8bf9 RBX: 0000000000000004 RCX: ffff88804b5e9e80 RDX: 0000000000000000 RSI: ffffffff8ef02800 RDI: ffffffff901bfc30 RBP: ffffc9000cbdfc60 R08: ffff88804b5e9e80 R09: 0000000000000005 R10: 0000000000000004 R11: 0000000000000000 R12: f8f8f8f8f8f8f8f8 R13: dffffc0000000000 R14: ffff888034116668 R15: 0000000000000001 FS: 00005555772e8500(0000) GS:ffff888125565000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c3d7900 CR3: 0000000083d7e000 CR4: 00000000003526f0 Call Trace: __refcount_dec include/linux/refcount.h:461 [inline] refcount_dec include/linux/refcount.h:476 [inline] ref_tracker_free+0x6fc/0x840 lib/ref_tracker.c:298 netdev_tracker_free include/linux/netdevice.h:4423 [inline] netdev_put include/linux/netdevice.h:4440 [inline] dev_put include/linux/netdevice.h:4466 [inline] mpoad_close+0x1fc/0x3e0 net/atm/mpc.c:889 vcc_destroy_socket net/atm/common.c:181 [inline] vcc_release+0x10f/0x580 net/atm/common.c:205 __sock_release net/socket.c:656 [inline] sock_close+0xc3/0x240 net/socket.c:1448 __fput+0x44f/0xa70 fs/file_table.c:469 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe20d19c799 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd9bdb8748 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007fe20d417da0 RCX: 00007fe20d19c799 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007fe20d417da0 R08: 0000000000000006 R09: 0000000000000000 R10: 00007fe20d417cb0 R11: 0000000000000246 R12: 00000000000f3cad R13: 00007fe20d41627c R14: 00000000000f3ac2 R15: 00007ffd9bdb8850 ---------------- Code disassembly (best guess), 5 bytes skipped: 0: e8 10 13 17 fd call 0xfd171315 5: 83 fb 01 cmp $0x1,%ebx 8: 7e 22 jle 0x2c a: 83 fb 02 cmp $0x2,%ebx d: 74 39 je 0x48 f: 83 fb 03 cmp $0x3,%ebx 12: 74 47 je 0x5b 14: 83 fb 04 cmp $0x4,%ebx 17: 75 68 jne 0x81 19: e8 77 0d 17 fd call 0xfd170d95 1e: 48 8d 3d 30 70 6d 0b lea 0xb6d7030(%rip),%rdi # 0xb6d7055 * 25: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2a: eb 66 jmp 0x92 2c: 85 db test %ebx,%ebx 2e: 74 3e je 0x6e 30: 83 fb 01 cmp $0x1,%ebx 33: 75 4c jne 0x81 35: e8 5b 0d 17 fd call 0xfd170d95 3a: 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