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 DBC543CF679 for ; Mon, 4 May 2026 12:23:29 +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=1777897411; cv=none; b=kmcqvV5R4/X53qjEfD87kGHQfatiXvpP0n8Lcy9ZjefnCiiUgQbif6p7CRxta/DQ76x67PWJebWEhflVuShekYlJ0O5a4KILkXrwL9d5zlf8xeC2N2gGvqMTeMdzF811rAIqDy8tkYMGQ+PUT4CkZt1hnAnnZ9FJBBO3D72ffAc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777897411; c=relaxed/simple; bh=vF7VQ8+k4CGeEfwzx516TY1r76rsGRzVHV+V8zEajr0=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=kiFgGvM7mKQ8efjznPu0NvSiFWx3VYxJNBWHcRhnBdJCjeR87gTGPldBSQtpbUJZjenRlFj/HgX+VdEP2rKT/qhDq9hHgZojse319UzvKsJcd1JFrCKFxurG8gwPR7UFenpoMwhJOATWKW6IwMa4ViRcrMJyQVYrZOVemva/uZU= 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 006d021491bc7-679c5ed0942so6987361eaf.1 for ; Mon, 04 May 2026 05:23:29 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777897409; x=1778502209; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=8Vxud8C2/N3Qd1nxI6ZswF3N3Q9HrHjw4PWPa6zeQOY=; b=e9jLuRMRmd3e0fumD52tKA/dxtB4Lu/it0rfm+FIspBRntlo8oIyhhcAlcb4XbtLJQ 2ptkPOC6uVMNRAPXYeFuMiSfDGbCrPGPgE29b4iOpzah6vFFekMVR3JXaPy9upptMl5+ HpVWmXyWuSaphOOUD4sR75AqKVogREVHHbmkNFgI3CuvLuAfKBnvvAdMFborTpgxH9YA S06xxb6eODWYJ9TWdDs3Xprt0gOwebhtw7THd91SOdkrbvHPuIyK6kiIXlk9pYr5qd8h r1HYOk96iAi04tYk8YBsmPBfESj1cIf4uzhk50t9iFBWib7794a7D5uU9ZpaEunm0APg rL4Q== X-Gm-Message-State: AOJu0YyuNtXfXJ044RV/e1KVQdeHgnbVBGDY/Cx+CWQQ6QDDdtxD0oUZ 0loTKMXd9cIbrhJs1ULAwh1LyxcwYE9Ai4VweKdAe/+vVFVgc4O7sxKqtNajm5KPwGPl/m4ORBT zH8E5ZH2IOFY322spbmpJFy+xasLqgG51c094BHFqKibJQI0qvVmd/gXeuFHXYw== Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:160c:b0:696:573c:9f0b with SMTP id 006d021491bc7-696979efb76mr4329643eaf.14.1777897408822; Mon, 04 May 2026 05:23:28 -0700 (PDT) Date: Mon, 04 May 2026 05:23:28 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69f88fc0.050a0220.3460d5.0004.GAE@google.com> Subject: [syzbot] [kernel?] WARNING: ODEBUG bug in smpboot_thread_fn From: syzbot To: linux-kernel@vger.kernel.org, peterz@infradead.org, syzkaller-bugs@googlegroups.com, tglx@kernel.org Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 6d35786de281 Merge tag 'for-linus' of git://git.kernel.org.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=126bf21f980000 kernel config: https://syzkaller.appspot.com/x/.config?x=f2e8ebfec4636d32 dashboard link: https://syzkaller.appspot.com/bug?extid=ae231e0552fa77b26ea1 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/b3ab34c4c807/disk-6d35786d.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/03f465478178/vmlinux-6d35786d.xz kernel image: https://storage.googleapis.com/syzbot-assets/29d261604425/bzImage-6d35786d.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+ae231e0552fa77b26ea1@syzkaller.appspotmail.com ------------[ cut here ]------------ ODEBUG: free active (active state 0) object: ffff888033a47278 object type: timer_list hint: br_ip6_multicast_port_query_expired+0x0/0x380 net/bridge/br_multicast.c:-1 WARNING: lib/debugobjects.c:632 at debug_print_object lib/debugobjects.c:629 [inline], CPU#1: rcuc/1/28 WARNING: lib/debugobjects.c:632 at __debug_check_no_obj_freed lib/debugobjects.c:1116 [inline], CPU#1: rcuc/1/28 WARNING: lib/debugobjects.c:632 at debug_check_no_obj_freed+0x405/0x550 lib/debugobjects.c:1146, CPU#1: rcuc/1/28 Modules linked in: CPU: 1 UID: 0 PID: 28 Comm: rcuc/1 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:debug_print_object lib/debugobjects.c:629 [inline] RIP: 0010:__debug_check_no_obj_freed lib/debugobjects.c:1116 [inline] RIP: 0010:debug_check_no_obj_freed+0x44a/0x550 lib/debugobjects.c:1146 Code: 89 44 24 20 e8 27 81 7f fd 48 8b 44 24 20 4c 8b 4d 00 4c 89 ef 48 c7 c6 a0 53 a7 8b 48 c7 c2 20 59 a7 8b 8b 0c 24 4d 89 f8 50 <67> 48 0f b9 3a 48 83 c4 08 4c 8b 6c 24 18 48 b9 00 00 00 00 00 fc RSP: 0018:ffffc90000a2fa90 EFLAGS: 00010246 RAX: ffffffff89f32240 RBX: ffffffff99a8edc0 RCX: 0000000000000000 RDX: ffffffff8ba75920 RSI: ffffffff8ba753a0 RDI: ffffffff8f933740 RBP: ffffffff8b4f5380 R08: ffff888033a47278 R09: ffffffff8b4f6700 R10: dffffc0000000000 R11: ffffffff81b0c180 R12: ffff888033a47400 R13: ffffffff8f933740 R14: ffff888033a47000 R15: ffff888033a47278 FS: 0000000000000000(0000) GS:ffff888126279000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb873a4da08 CR3: 000000004cc78000 CR4: 00000000003526f0 Call Trace: slab_free_hook mm/slub.c:2620 [inline] slab_free mm/slub.c:6250 [inline] kfree+0x13e/0x6c0 mm/slub.c:6565 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x228/0x560 lib/kobject.c:737 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core kernel/rcu/tree.c:2869 [inline] rcu_cpu_kthread+0x99e/0x1470 kernel/rcu/tree.c:2957 smpboot_thread_fn+0x541/0xa50 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: 89 44 24 20 mov %eax,0x20(%rsp) 4: e8 27 81 7f fd call 0xfd7f8130 9: 48 8b 44 24 20 mov 0x20(%rsp),%rax e: 4c 8b 4d 00 mov 0x0(%rbp),%r9 12: 4c 89 ef mov %r13,%rdi 15: 48 c7 c6 a0 53 a7 8b mov $0xffffffff8ba753a0,%rsi 1c: 48 c7 c2 20 59 a7 8b mov $0xffffffff8ba75920,%rdx 23: 8b 0c 24 mov (%rsp),%ecx 26: 4d 89 f8 mov %r15,%r8 29: 50 push %rax * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: 48 83 c4 08 add $0x8,%rsp 33: 4c 8b 6c 24 18 mov 0x18(%rsp),%r13 38: 48 rex.W 39: b9 00 00 00 00 mov $0x0,%ecx 3e: 00 fc add %bh,%ah --- 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