From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-il1-f207.google.com (mail-il1-f207.google.com [209.85.166.207]) (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 BDD6121E0BB for ; Tue, 14 Oct 2025 01:28:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.207 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760405312; cv=none; b=WvDrM8G78Yfa1F60jm3Kv8pF448BTxh9mYtoXrIPeEFiNeZ0B8MmVGt2wTHGPZCVPGFxS+9qjxD5hLmaLVEiYiX77weoWC9cpSzXAYp3cWiUxRzLOMPs3zLHMDPguTDTjObCE9OPMVndyFa+f630f2Lp0JzLvm54PcLdwGMLXv8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760405312; c=relaxed/simple; bh=2iaJRMBuABmsLpaRzlvXY3A/+R7uQb2O6fB58p9cxbs=; 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:a05:6e02:2489:b0:42f:9649:56b4 with SMTP id e9e14a558f8ab-42f96495934mr173412685ab.13.1760405309702; Mon, 13 Oct 2025 18:28:29 -0700 (PDT) Date: Mon, 13 Oct 2025 18:28:29 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <68eda73d.a70a0220.b3ac9.0022.GAE@google.com> Subject: [syzbot] [fs?] INFO: rcu detected stall in unwind_next_frame (5) From: syzbot To: brauner@kernel.org, jack@suse.cz, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@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: 07fdad3a9375 Merge tag 'net-next-6.18' of git://git.kernel.. git tree: net-next console output: https://syzkaller.appspot.com/x/log.txt?x=11eb4b34580000 kernel config: https://syzkaller.appspot.com/x/.config?x=5bcbbf19237350b5 dashboard link: https://syzkaller.appspot.com/bug?extid=0f5d9b52b3f467f78d36 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=10d1b458580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/2ef8bd056945/disk-07fdad3a.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/a9847877fb22/vmlinux-07fdad3a.xz kernel image: https://storage.googleapis.com/syzbot-assets/d00de7416031/bzImage-07fdad3a.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+0f5d9b52b3f467f78d36@syzkaller.appspotmail.com rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=8e14/1/0x4000000000000000 softirq=18748/18750 fqs=1 rcu: (detected by 1, t=10502 jiffies, g=12053, q=759 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5982 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:memset_orig+0x75/0xb0 arch/x86/lib/memset_64.S:92 Code: 89 47 30 48 89 47 38 48 8d 7f 40 75 d8 0f 1f 84 00 00 00 00 00 89 d1 83 e1 38 74 14 c1 e9 03 66 0f 1f 44 00 00 ff c9 48 89 07 <48> 8d 7f 08 75 f5 83 e2 07 74 0a ff ca 88 07 48 8d 7f 01 75 f6 4c RSP: 0018:ffffc90000007c80 EFLAGS: 00000002 RAX: 0000000000000000 RBX: ffff888056c2a340 RCX: 0000000000000001 RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc90000007ca0 RBP: 0000000000000000 R08: ffffc90000007caf R09: 0000000000000000 R10: ffffc90000007ca0 R11: fffff52000000f96 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffffff8b6cf420 R15: ffff8880b8627bc0 FS: 000055558512b500(0000) GS:ffff888125d3b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffba57b3000 CR3: 000000003058e000 CR4: 00000000003526f0 Call Trace: debug_object_activate+0x38/0x420 lib/debugobjects.c:806 debug_hrtimer_activate kernel/time/hrtimer.c:438 [inline] debug_activate kernel/time/hrtimer.c:477 [inline] enqueue_hrtimer+0x30/0x3a0 kernel/time/hrtimer.c:1081 __run_hrtimer kernel/time/hrtimer.c:1794 [inline] __hrtimer_run_queues+0x656/0xc60 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:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 6b ec f1 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc90003987818 EFLAGS: 00000206 RAX: 0b2e9023536a4b00 RBX: 0000000000000000 RCX: 0b2e9023536a4b00 RDX: 0000000000000001 RSI: ffffffff8d9c68ab RDI: ffffffff8bc03b60 RBP: ffffffff8172ad05 R08: 0000000000000000 R09: ffffffff8172ad05 R10: ffffc900039879d8 R11: ffffffff81ab4450 R12: 0000000000000002 R13: ffffffff8e13a960 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1169 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 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:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2422 [inline] slab_free mm/slub.c:4695 [inline] kmem_cache_free+0x18f/0x400 mm/slub.c:4797 file_free fs/file_table.c:71 [inline] __fput+0x6c2/0xa70 fs/file_table.c:481 fput_close_sync+0x119/0x200 fs/file_table.c:573 __do_sys_close fs/open.c:1587 [inline] __se_sys_close fs/open.c:1572 [inline] __x64_sys_close+0x7f/0x110 fs/open.c:1572 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ffba558db2a Code: 48 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c 24 0c e8 43 91 02 00 8b 7c 24 0c 89 c2 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 36 89 d7 89 44 24 0c e8 a3 91 02 00 8b 44 24 RSP: 002b:00007fffa7a45e40 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007ffba558db2a RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000003 R08: 00007fffa7a4578c R09: 0079746972756365 R10: 00007fffa7a457f0 R11: 0000000000000293 R12: 0000000000000000 R13: 00007ffba57b1280 R14: 0000000000000003 R15: 00007fffa7a45ef0 rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g12053 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=8549 rcu: rcu_preempt kthread starved for 10500 jiffies! g12053 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:26760 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+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4b9/0x870 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 --- This report is generated by a bot. 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