From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f70.google.com (mail-ot1-f70.google.com [209.85.210.70]) (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 02F31139D for ; Tue, 27 Jan 2026 04:53:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.70 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769489584; cv=none; b=ELpK4ywuYTN1WFNHgEFUA2Xrl8B4tATFSTwgEjJQZYh9Bz3qTHupXwBIKfPU46mJJd0LLA2LlaWjxJuXRcfPQHsKhBxOI2V0GqSOUiebx5EqbH1Ds2UM9O42JbZOR1p7opfkXRswvL5FWbRMbguWCMtjNtp3AKKzNy/ri0OORRc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769489584; c=relaxed/simple; bh=hVAAYVIfodD6IJ6MqNkdBjhViX00Lb8mTev4BWfEFKA=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=diUFSfS8E2Ga+P/mmvp3ToKTFvZ1QRzc1yJAJqVmBD0Y7MwjQ2ZkE5XeUsZPQ+L28QB1dRb3xEpjQ/97oY5KwtSI6ICKG6+J3Lgt+zHEu7Ki5fP4B+GDSzkWaF/u0HfbEIFTpD1i+3Wehf6wbqRyF5HaFmnCPrYkyrpR8kJGoWI= 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=209.85.210.70 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-f70.google.com with SMTP id 46e09a7af769-7cfd107ef0eso20233348a34.1 for ; Mon, 26 Jan 2026 20:53:02 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769489582; x=1770094382; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=89+LV5E9D8AVhKCxyRMbL4zmgA6Idoh/fNHb9jMz/6o=; b=FyeB8z2C5CMLZlMu7rVC1+bIN52YROCJDtSH4g0RZpoeqG8Zs7egqkxfopgzfj+Fpr VmB7WnJyV1YomG/pkJYBd4XDFGuBXNaRyifmZlYqfOuaMVr/pl72NeVlDYDwvKr1E+Q2 HU5Fg4Fq+X1VyaLifWaEYqi2YxwDhOlD7/shRAAePpSObJKsPkjSQfI6bfo8aDMLEdtp JyzJmYgb2rkI35L+lxt6AkmeAvRhqm2wCvNlP5Naes7/TkZfHiNdhgrKI6X/ZCW7xB1q AMQH0SjXx4qsAzb1zdQuAlF4JJTTHlD9vxz/OrbhS0XGUVIRPQUi/gWHL5gQD8gp9LhA t3ew== X-Forwarded-Encrypted: i=1; AJvYcCVzzIkakTUEGc/JtDd8Df4V8wdV+GsnS2L4AEZzP/1Qpk8g3LrPpqCjLmNo7cNiiqVGWJirr/qtpdT79Co=@vger.kernel.org X-Gm-Message-State: AOJu0YzbD079lrF7vGbIJBgwkwlj2iwpmU0gZZ9z12B1llnvYpupZZ/f QSeoyizxpklCeim1MLphFemD85aFflQO/+vk41N3vwfXjIHVQQoeNWT1hFZZbZ3iZtN53HJjCjn BvsqP0BklgvUfiaf8L6ES+jANOXfph/22FO9ryTyOLjlyrrHVghAeI8dLdvk= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:201c:b0:662:c6ea:cec6 with SMTP id 006d021491bc7-662f2046872mr353083eaf.26.1769489581899; Mon, 26 Jan 2026 20:53:01 -0800 (PST) Date: Mon, 26 Jan 2026 20:53:01 -0800 In-Reply-To: <20260127040209.16388-1-kartikey406@gmail.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <697844ad.050a0220.c9109.0014.GAE@google.com> Subject: Re: [syzbot] [mm?] INFO: rcu detected stall in schedule_tail (8) From: syzbot To: kartikey406@gmail.com, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: INFO: rcu detected stall in schedule_timeout rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 0, t=10502 jiffies, g=14829, q=576 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10504 (4294959943-4294949439), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10505 jiffies! g14829 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:28408 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0xfe4/0x5e10 kernel/sched/core.c:6867 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7194 irqentry_exit+0x17b/0x670 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__free_object+0x2b5/0x400 lib/debugobjects.c:524 Code: 00 0f 85 f7 00 00 00 48 c7 43 08 e0 7b 0d 9b 4d 85 e4 0f 84 66 ff ff ff e8 38 50 1f fd 9c 58 f6 c4 02 0f 85 12 01 00 00 fb 5b <5d> 41 5c 41 5d c3 cc cc cc cc 48 c7 c7 60 d2 15 8f e8 25 fd 89 06 RSP: 0018:ffffc90000157a20 EFLAGS: 00000246 RAX: 0000000000000002 RBX: ffff88801f332968 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8dc4581b RDI: ffffffff8bfa35a0 RBP: ffff8880b853c680 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000200 R13: ffff8880532ca5e8 R14: ffffc90000157b58 R15: 1ffff9200002af4c free_object lib/debugobjects.c:532 [inline] debug_object_free+0x295/0x550 lib/debugobjects.c:976 schedule_timeout+0x137/0x280 kernel/time/sleep_timeout.c:103 rcu_gp_fqs_loop+0x1a9/0xb00 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x21e/0x320 kernel/rcu/tree.c:2285 kthread+0x3b3/0x730 kernel/kthread.c:463 ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 6551 Comm: syz.0.34 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202 Code: 90 f3 0f 1e fa 53 48 8b 74 24 08 48 89 fb 48 83 c7 18 e8 4a 8d 69 f6 48 89 df e8 32 db 69 f6 e8 9d 4e 95 f6 fb bf 01 00 00 00 e2 29 5a f6 65 8b 05 ab da 6a 08 85 c0 74 06 5b e9 91 4a 00 00 RSP: 0018:ffffc900040afe40 EFLAGS: 00000202 RAX: 0000000005276bf1 RBX: ffff88802e958000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8dc4581b RDI: 0000000000000001 RBP: ffff88807cc28968 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff88807cc28000 R13: 0000000100000000 R14: 0000000000000007 R15: 0000000000000000 FS: 00007f02334076c0(0000) GS:ffff8881245d9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000058 CR3: 00000000533f5000 CR4: 00000000003526f0 Call Trace: spin_unlock_irq include/linux/spinlock.h:401 [inline] __set_current_blocked kernel/signal.c:3222 [inline] set_current_blocked+0xdd/0x120 kernel/signal.c:3206 __do_sys_rt_sigreturn+0x1a2/0x2c0 arch/x86/kernel/signal_64.c:263 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f023253c0d9 Code: 11 06 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 0c 25 RSP: 002b:00007f0233406400 EFLAGS: 00000206 ORIG_RAX: 000000000000000f RAX: ffffffffffffffda RBX: 00007f0232815fa8 RCX: 00007f023253c0d9 RDX: 00007f0233406400 RSI: 00007f0233406530 RDI: 0000000000000021 RBP: 00007f0232815fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f0232816038 R14: 00007ffc229935c0 R15: 00007ffc229936a8 Tested on: commit: fcb70a56 Merge tag 'vfs-6.19-rc8.fixes' of git://git.k.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=128aa05a580000 kernel config: https://syzkaller.appspot.com/x/.config?x=f1fac0919970b671 dashboard link: https://syzkaller.appspot.com/bug?extid=42836f91edd58eb82c6a compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 patch: https://syzkaller.appspot.com/x/patch.diff?x=11be505a580000