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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" X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: EB6CCA0013 X-Stat-Signature: fpdcxpo5nmckpntynnmgdg9e95gc9yya X-Rspam-User: X-HE-Tag: 1785888109-925858 X-HE-Meta: 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 s0MnyTKn 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 zHS5nJd5 wq+81YBMqKZwkuVcsMPKyzNK8Rwwhf/PAVVp00NMKietpEiRFo4I3PHaBaFuMvOdQHEKkM/zvCYcH+jeKvhfA7vgKH4XETV9fKkaNOJ4QKOVsZp6Ddkwl/loLr4rCNkTuqyMPnlQTlOIrlE1SOs3vUe9KWKwm4l6IHVTjILJ/721pyM0X889i7e01Hky5dS6UP6PzZbZ/JETXcXnkoBQB/cLcdQ1J3LRLB7UzpZxBt3suhTIGWtNiPqF/4vIyW0zeii0n1rGqlQ/6LB/qXZI0txiINda2TN+bJmQlig2fjTphuhi10mDKInQlFhwdBlDHR5+kxCxbcxDk79JwlT4bCVNmRGaA1bdkQ3cojHXfO4HsOSe9miUdHC1pFQrAlRdntM2zUGkmSyTXgQ0zBDaQX1HX/oQSKEi Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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