From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-io1-f78.google.com (mail-io1-f78.google.com [209.85.166.78]) (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 9317F14A0B5 for ; Thu, 9 Oct 2025 10:32:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.78 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760005947; cv=none; b=A+EtM85HwG952v1lq4vPXbRU0f2oQO2DDYuVSPZwFgDq/xTI/+XQmP/s1tXDXjzFLOnR38N1CcL7nh0C10YaAwOGLPVadGe1STJamDc/WxRSskkBUG6SyOclfy36LSMqo0Em0sWP1uIeRmk8RE1acb3IxEka70TPBaaDV3xrZz4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760005947; c=relaxed/simple; bh=k5R/vceqDjN5sCzQFkq785u7pH5+CTtIEZKL5Szr+aA=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; 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List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6602:3c3:b0:88d:7956:2e04 with SMTP id ca18e2360f4ac-93bd1996632mr790580439f.19.1760005944707; Thu, 09 Oct 2025 03:32:24 -0700 (PDT) Date: Thu, 09 Oct 2025 03:32:24 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <68e78f38.a70a0220.126b66.0000.GAE@google.com> Subject: [syzbot] [fs?] INFO: rcu detected stall in eventpoll_release_file (2) From: syzbot To: brauner@kernel.org, jack@suse.cz, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: d104e3d17f7b Merge tag 'cxl-for-6.18' of git://git.kernel... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1386692f980000 kernel config: https://syzkaller.appspot.com/x/.config?x=7fbc67b290d20c8 dashboard link: https://syzkaller.appspot.com/bug?extid=acf1d29334968f95c8aa compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=144f4304580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14a3b942580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/1b9be99eac71/disk-d104e3d1.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/c53f49fb5e7d/vmlinux-d104e3d1.xz kernel image: https://storage.googleapis.com/syzbot-assets/472bbd39f27e/bzImage-d104e3d1.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+acf1d29334968f95c8aa@syzkaller.appspotmail.com rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 ticks this GP) idle=1a74/1/0x4000000000000000 softirq=13502/13502 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5871/1:b..l rcu: (detected by 1, t=10504 jiffies, g=10797, q=541 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5864 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:advance_sched+0x178/0xc90 net/sched/sch_taprio.c:932 Code: db 74 29 49 8d 7c 24 c0 be ff ff ff ff e8 70 81 d7 01 89 c3 31 ff 89 c6 e8 55 24 61 f8 85 db 0f 84 ab 06 00 00 e8 08 20 61 f8 05 e8 01 20 61 f8 4d 8d 74 24 f0 4c 89 f1 48 c1 e9 03 48 b8 00 RSP: 0018:ffffc90000007c70 EFLAGS: 00000006 RAX: ffffffff895d3f38 RBX: 0000000000000001 RCX: ffff8880785cdac0 RDX: 0000000000010000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000000f7c R12: ffff888023610340 R13: ffff888023610000 R14: dffffc0000000000 R15: ffff888032438800 FS: 00007f2a2f406880(0000) GS:ffff888126388000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f21335dba90 CR3: 0000000077c54000 CR4: 00000000003526f0 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1058 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__ep_remove+0x126/0x710 fs/eventpoll.c:855 Code: 35 00 00 74 08 4c 89 e7 e8 57 49 d9 ff 89 6c 24 0c 4d 8b 34 24 4c 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 <74> 08 4c 89 f7 e8 30 49 d9 ff 49 8d 6f 50 49 39 2e 0f 84 95 00 00 RSP: 0018:ffffc90004347ce0 EFLAGS: 00000246 RAX: 1ffff1100fc09fd0 RBX: ffff8880304fcc3c RCX: dffffc0000000000 RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90004347c60 RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000868f8c R12: ffff88807be122f8 R13: 1ffff1100f7c245f R14: ffff88807e04fe80 R15: ffff8880304fcc00 eventpoll_release_file+0xdb/0x310 fs/eventpoll.c:1136 eventpoll_release include/linux/eventpoll.h:57 [inline] __fput+0x839/0xa70 fs/file_table.c:459 fput_close_sync+0x119/0x200 fs/file_table.c:573 __do_sys_close fs/open.c:1589 [inline] __se_sys_close fs/open.c:1574 [inline] __x64_sys_close+0x7f/0x110 fs/open.c:1574 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2a2eca7407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffefbabcad0 EFLAGS: 00000202 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 00007f2a2f406880 RCX: 00007f2a2eca7407 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007f2a2f4066e8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffefbabcb90 R14: 0000000000000000 R15: 0000000000000000 task:syz-executor758 state:R running task stack:21000 pid:5871 tgid:5871 ppid:5851 task_flags:0x400140 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707 RIP: 0010:lock_release+0x2b5/0x3e0 kernel/locking/lockdep.c:5893 Code: 51 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 56 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 6b 6d ad 10 <48> 3b 44 24 28 0f 85 8b 00 00 00 48 83 c4 30 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc900042862f0 EFLAGS: 00000206 RAX: e2c579f95b601100 RBX: 0000000000000206 RCX: e2c579f95b601100 RDX: 0000000000000001 RSI: ffffffff8d6f55e3 RDI: ffffffff8b9eea60 RBP: ffff8880316de618 R08: ffffc90004286cf0 R09: 0000000000000000 R10: ffffc90004286478 R11: fffff52000850c91 R12: 0000000000000001 R13: 0000000000000001 R14: ffffffff8dd3b220 R15: ffff8880316ddac0 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1169 [inline] unwind_next_frame+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 unpoison_slab_object mm/kasan/common.c:342 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:368 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4946 [inline] slab_alloc_node mm/slub.c:5245 [inline] kmem_cache_alloc_node_noprof+0x433/0x710 mm/slub.c:5297 kmalloc_reserve+0xbd/0x290 net/core/skbuff.c:579 __alloc_skb+0x142/0x2d0 net/core/skbuff.c:670 alloc_skb include/linux/skbuff.h:1383 [inline] nlmsg_new include/net/netlink.h:1055 [inline] rtmsg_fib+0xea/0x4c0 net/ipv4/fib_semantics.c:552 fib_table_insert+0xd64/0x1b50 net/ipv4/fib_trie.c:1380 fib_magic+0x2c4/0x390 net/ipv4/fib_frontend.c:1134 fib_add_ifaddr+0x38d/0x5f0 net/ipv4/fib_frontend.c:1171 fib_netdev_event+0x382/0x490 net/ipv4/fib_frontend.c:1516 notifier_call_chain+0x1b6/0x3e0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline] call_netdevice_notifiers net/core/dev.c:2281 [inline] __dev_notify_flags+0x18d/0x2e0 net/core/dev.c:-1 netif_change_flags+0xe8/0x1a0 net/core/dev.c:9705 do_setlink+0xc55/0x41c0 net/core/rtnetlink.c:3151 rtnl_changelink net/core/rtnetlink.c:3769 [inline] __rtnl_newlink net/core/rtnetlink.c:3928 [inline] rtnl_newlink+0x1619/0x1c80 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x7cc/0xb70 net/core/rtnetlink.c:6954 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 __sys_sendto+0x3bd/0x520 net/socket.c:2244 __do_sys_sendto net/socket.c:2251 [inline] __se_sys_sendto net/socket.c:2247 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2247 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f213324e8fc RSP: 002b:00007f21333ff670 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f2133401080 RCX: 00007f213324e8fc RDX: 000000000000002c RSI: 00007f21334010d0 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007f21333ff6c4 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 R13: 0000000000000000 R14: 00007f21334010d0 R15: 0000000000000000 rcu: rcu_preempt kthread timer wakeup didn't happen for 10503 jiffies! g10797 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=5145 rcu: rcu_preempt kthread starved for 10504 jiffies! g10797 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26728 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 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 syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. 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