From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f78.google.com (mail-ot1-f78.google.com [209.85.210.78]) (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 16F851E511 for ; Wed, 5 Aug 2026 00:01:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.78 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785888111; cv=none; b=inxE/NsnOVKMlingVRP46DTSC120iV7c6vbNVEHN/7y56CNxqsgZAmNdQDfQSAT8V8TjCVqWECxgGAGV6iXJRJFBcJpDSKYio0nXanxvAXkZ6YRWL+vRjbYOfkIZs9R0yWVufRoERMbaiceUDUH7El8foryNpo7zrah9ddi7AHE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785888111; c=relaxed/simple; bh=UWNLDggKpTAFTuc9nAwlzdDYYY737F2gSbSQrI2oGX4=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=mZgqEY8WBUskFvvlaRWCxbRHANO9+WE+Ext/dg9xO68RgG7KD8JYgz6EFMESa6r0SVQ5MNBOqggYFkuyNDGEdKH0aLCtt/Le8sFCXVQZl2rX4TkCB9LQiYiSSCsD61KLbj36UV22vtg1UQHHjsSmOs6ZCEh9yzhHwalAGzfvOOw= 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=209.85.210.78 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-f78.google.com with SMTP id 46e09a7af769-7eb64224fd2so697851a34.0 for ; Tue, 04 Aug 2026 17:01:49 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785888109; x=1786492909; 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=7ljke+Jb2WS/MuuNhu+Gojm59EgN+Rdq5k66c0XmNA4=; b=QHhwEORUw225P6QthYnQ0ODGx3EV4JNg7ZAI5vChO19Jq9cMfOdOlmB7Si2oEwAIKs u28t70yELge9iqMFuJsG1rGG3JuVbaIjssfNbpapzmpYXswQzwt3Zl8M2jFBoHtP7+/u 3Tgo2myzHCZH9Ro9Oy/cWQrFXKCZNuiGJOPFNXiT8vrwUThsEkrr2H3DHHWVm1PHrOtT awE+qwjr4iCM46vyCSk8F/hMccmU32z7fm85Y4FEMYga7HpzdYt29D5pZueY06WJzcRW 2VYr5ME3XlBHkLp4ld0T+Cwl2IoBdQYlkwARUur0obKUZX47/LWk72D/cWqvDq3eTXKp 7aaQ== X-Forwarded-Encrypted: i=1; AHgh+RoTNzucmUUhTIrpVt/JQcjhEVtMZRIEZUewtltnQszi9fzCM/fsbdhmvss5Bt+gNvl+wjBlVBQdHo2lJog=@vger.kernel.org X-Gm-Message-State: AOJu0YxaUT0PAHWItRlysXcVuyjDuhl658hfgfIHH7MLNQ6ZACNR9ojL aF5DxfT2yRUz0X+cAYKOHrvbNX2IUJhxdh06XYr98fqDd3rMkjGuAvyMhvKMwxGOIi6CYCcCM7S zcMwSDiZFf3q0n1mnA5ZqhemFdVi2PPH2HWAwmrwY7rTcuNL4hwuXRlz2ng0= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:188e:b0:6ae:46cd:e908 with SMTP id 006d021491bc7-6ae96ec7afdmr1717347eaf.17.1785888108906; Tue, 04 Aug 2026 17:01:48 -0700 (PDT) Date: Tue, 04 Aug 2026 17:01:48 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a727d6c.9511d2ce.1fc5b9.035e.GAE@google.com> Subject: [syzbot] [mm?] INFO: rcu detected stall in khugepaged (3) From: syzbot To: akpm@linux-foundation.org, hannes@cmpxchg.org, jackmanb@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.com, surenb@google.com, syzkaller-bugs@googlegroups.com, vbabka@kernel.org, ziy@nvidia.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 3708dd948844 Merge tag 'pm-7.2-rc6' of git://git.kernel.or.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=11ac703e580000 kernel config: https://syzkaller.appspot.com/x/.config?x=4e38b15c29e6a1d9 dashboard link: https://syzkaller.appspot.com/bug?extid=d2401aeb74cc84adba04 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/c0390423374e/disk-3708dd94.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/3130bf9c5dbf/vmlinux-3708dd94.xz kernel image: https://storage.googleapis.com/syzbot-assets/2c8fbf8aeba4/bzImage-3708dd94.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+d2401aeb74cc84adba04@syzkaller.appspotmail.com rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P37/1:b..l rcu: (detected by 1, t=10503 jiffies, g=32265, q=1190 ncpus=2) task:khugepaged state:R running task stack:26864 pid:37 tgid:37 ppid:2 task_flags:0x200040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_release+0x2d7/0x3c0 kernel/locking/lockdep.c:5893 Code: 7d ca 11 00 00 00 00 eb b5 e8 55 ad 2e 0a f7 c3 00 02 00 00 74 b9 65 48 8b 05 45 38 ca 11 48 3b 44 24 28 75 44 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d a2 33 b8 RSP: 0018:ffffc90000ad7028 EFLAGS: 00000286 RAX: 623a32d217845600 RBX: 0000000000000206 RCX: 0000000000000046 RDX: 0000000000000000 RSI: ffffffff8e4b3351 RDI: ffffffff8c4bdd80 RBP: ffff888020ea0ba0 R08: ffffc90000ad74d0 R09: 0000000000000000 R10: ffffc90000ad7158 R11: fffff5200015ae2d R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff8eb59c60 R15: ffff888020ea0000 rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0x1baa/0x2550 arch/x86/kernel/unwind_orc.c:709 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:165 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0xc1e/0xd10 mm/page_alloc.c:2950 __folio_put+0x4b3/0x590 mm/swap.c:112 folio_put_refs include/linux/mm.h:2144 [inline] collapse_file mm/khugepaged.c:2643 [inline] collapse_scan_file+0x4285/0x5210 mm/khugepaged.c:2773 collapse_single_pmd+0x2b1/0x3da0 mm/khugepaged.c:2808 collapse_scan_mm_slot mm/khugepaged.c:2913 [inline] khugepaged_do_scan mm/khugepaged.c:2993 [inline] khugepaged+0xa00/0x1780 mm/khugepaged.c:3048 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 --- 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