From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f198.google.com (mail-oi1-f198.google.com [209.85.167.198]) (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 C5A204B4043 for ; Mon, 12 Oct 2026 15:44:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.198 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791819880; cv=none; b=aWBHngUHNTInkFMLPAqrtG/i+idmBnnt29WcTs5GimUIRxHzoYsgRAHhfDwJUOxyETqXmE+bH71yAushhaXj9IMVyPtTcF8nFDWESVeylIcFTBf7hILb3067PMoDgtBoeJ7cxDofYNI1DIJVdJMm6cxLFgbWmiEHmc0paVnF5L4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791819880; c=relaxed/simple; bh=bR1O7d6qQN9Efb4Kbpe+rTLzsK7TGqxLRmmK6Ui3Ass=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=Yyyupp7REvqf/GsHcY3HPhlCLYDuMtTDBb6I6e8jYR6W+i61Ie0CyAd6f2s9DRw15XChOa8mRwdkm2XFO+4NuaoihEJXPIvkPYUgUlsvQTkSUKVSBTBbx1lpNH9/O8grb5oScZ8DIFreOnLsvegmnt5QjbSh0MMTfkHXOAZvuFI= 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=209.85.167.198 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-oi1-f198.google.com with SMTP id 5614622812f47-4dab94dc3e7so3611857b6e.0 for ; Mon, 12 Oct 2026 08:44:38 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1791819878; x=1792424678; 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=GPDFFFGSrqI9ZKgzKXufTUNby0rH4X7Rocq6YYaTbNU=; b=m65v63gOEyjDB+iXvGjlAIhmBzQZtqlZ4V5iodh/Fr19U2x/nxVHSyTmOxBIXRFQGg Lk9KIkOC07meLjBCuW5JVV7RtM3lJk1RzQP0xfApcOK+GzEM2kZVU95xO682uvOfQdnl urV0Yz2lJ44jDCFh/2ZTAyVG/6ATZgRLbZinYh0qDguQNit5+w7Z4CJ70CZ48kIpN9yu NRxe7MX/9niwSR3FV2JE4kT4tMlIg1OV3/7KaibzTEGILNYjmnE5CreIeTjE49ie17Aa C7nXPFk43RZ8a4Naf7rpe7mnsNNYRHpN3C17Eal2PE05ywk6ySc4MTVzgFtFwpRYon/8 iEDw== X-Forwarded-Encrypted: i=1; AKwUvBzwfs425NadxOM64uFuMavp+0hFTPvPoer/c3JJaFJY7FeZHyT2iP3nz7fNUdh8F7oQmyqd4Ec=@vger.kernel.org X-Gm-Message-State: AFq9FYLFTMaPz5KHQA9WQoGEjRM7OKYdRDGptHE7vDCPJIXW+ZkqvmM5 t9mUkIT1P8Av07Mh+rF9jzPDUyxZPccy8+uZQrb72Pby65OnR1/MlWBhLWZ46arQCoYNTkSfpBZ vbyeuqiAUbLYr9pIRg69hlGeAUOHyCDVv5Wvdy0hB+ZpsrfDAi9hTS3QrZ+0= Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:680a:b0:4fb:6402:a8ca with SMTP id 5614622812f47-50c4e685340mr10902686b6e.21.1791819877745; Mon, 12 Oct 2026 08:44:37 -0700 (PDT) Date: Mon, 12 Oct 2026 08:44:37 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6acd0065.a150a118.27e199.004d.GAE@google.com> Subject: [syzbot] [lvs?] INFO: rcu detected stall in ip_vs_estimation_kthread (2) From: syzbot To: coreteam@netfilter.org, davem@davemloft.net, edumazet@kernel.org, fw@strlen.de, horms@verge.net.au, ja@ssi.bg, kuba@kernel.org, linux-kernel@vger.kernel.org, lvs-devel@vger.kernel.org, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, pabeni@redhat.com, pablo@netfilter.org, phil@nwl.cc, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 7b63ef2d55f2 Merge tag 'for-7.3-rc6-tag' of git://git.kern.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16feaa8e580000 kernel config: https://syzkaller.appspot.com/x/.config?x=23e5acac5c98285f dashboard link: https://syzkaller.appspot.com/bug?extid=022ec9322756662013b5 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/6a3c98d82e9c/disk-7b63ef2d.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/3d921ef6c68c/vmlinux-7b63ef2d.xz kernel image: https://storage.googleapis.com/syzbot-assets/9d4e9981e5b9/bzImage-7b63ef2d.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+022ec9322756662013b5@syzkaller.appspotmail.com rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5285/3:b..l rcu: (detected by 0, t=10503 jiffies, g=348101, q=1610 ncpus=2) task:syz-executor state:R running task stack:28200 pid:5285 tgid:5285 ppid:32677 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5533 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7284 preempt_schedule_common+0x7f/0xd0 kernel/sched/core.c:7463 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:201 [inline] _raw_spin_unlock+0x41/0x50 kernel/locking/spinlock.c:213 spin_unlock include/linux/spinlock.h:401 [inline] filemap_map_pages+0x1aba/0x2170 mm/filemap.c:3997 do_fault_around mm/memory.c:5958 [inline] do_read_fault mm/memory.c:5991 [inline] do_fault mm/memory.c:6134 [inline] do_pte_missing+0x20ae/0x34b0 mm/memory.c:4700 handle_pte_fault mm/memory.c:6558 [inline] __handle_mm_fault mm/memory.c:6707 [inline] handle_mm_fault+0x1a53/0x3750 mm/memory.c:6876 do_user_addr_fault+0xa4f/0x1340 arch/x86/mm/fault.c:1343 handle_page_fault arch/x86/mm/fault.c:1483 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1536 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595 RIP: 0033:0x7f5254b3f7c0 RSP: 002b:00007f5254f4fc58 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 00007f5254f4fc60 RCX: 00007f5254bc6c4c RDX: 0000000000000000 RSI: 0000000000000018 RDI: 00007f5254f4fc60 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 R10: 000055557d62f7d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 00000000001e199a R15: 00007f5254f4fe40 rcu: rcu_preempt kthread starved for 737 jiffies! g348101 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->cpu=1 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:27496 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5533 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7284 __schedule_loop kernel/sched/core.c:7361 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7376 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330 kthread+0x38b/0x480 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 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 2226 Comm: ipvs-e:321:0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 RIP: 0010:netif_skb_features+0xc5/0xf20 net/core/dev.c:3914 Code: 4c 89 74 24 10 49 8b 45 00 48 89 44 24 18 48 8d 98 b8 00 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 <74> 08 48 89 df e8 b1 57 85 f8 4c 8b 33 48 8b 44 24 10 48 8d b8 d0 RSP: 0018:ffffc90000a17da0 EFLAGS: 00000246 RAX: 1ffff1100547bc17 RBX: ffff88802a3de0b8 RCX: dffffc0000000000 RDX: 8000000000000300 RSI: 0000000000000100 RDI: ffff8881d9ce2dc0 RBP: ffffc90000a17ea0 R08: 0000000000000100 R09: 1ffffffff20f4ccf R10: dffffc0000000000 R11: fffffbfff20f4cd0 R12: dffffc0000000000 R13: ffff8881d9ce2dd0 R14: ffff8881d9ce2dc0 R15: ffff88802a3de000 FS: 0000000000000000(0000) GS:ffff888124dc6000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5254b3f7c0 CR3: 000000007eb18000 CR4: 00000000003526f0 Call Trace: validate_xmit_skb+0xa0/0x1820 net/core/dev.c:4095 __dev_queue_xmit+0xb01/0x3920 net/core/dev.c:4945 dev_queue_xmit include/linux/netdevice.h:3464 [inline] neigh_hh_output include/net/neighbour.h:544 [inline] neigh_output include/net/neighbour.h:558 [inline] ip_finish_output2+0xbda/0x10b0 net/ipv4/ip_output.c:236 NF_HOOK_COND include/linux/netfilter.h:314 [inline] ip_output+0x29f/0x450 net/ipv4/ip_output.c:437 synproxy_send_client_synack+0x89b/0xde0 net/netfilter/nf_synproxy_core.c:487 nft_synproxy_eval_v4+0x362/0x4e0 net/netfilter/nft_synproxy.c:59 nft_synproxy_do_eval+0x389/0x5d0 net/netfilter/nft_synproxy.c:142 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x48d/0x1b10 net/netfilter/nf_tables_core.c:285 nft_do_chain_ipv4+0x195/0x290 net/netfilter/nft_chain_filter.c:24 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:280 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:323 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:325 __netif_receive_skb_one_core net/core/dev.c:6297 [inline] __netif_receive_skb net/core/dev.c:6410 [inline] process_backlog+0xa6b/0x18b0 net/core/dev.c:6761 __napi_poll+0xaa/0x330 net/core/dev.c:7830 napi_poll net/core/dev.c:7893 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:8050 handle_softirqs+0x226/0x860 kernel/softirq.c:645 __do_softirq kernel/softirq.c:679 [inline] invoke_softirq kernel/softirq.c:519 [inline] __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:758 irq_exit_rcu+0x9/0x30 kernel/softirq.c:775 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:finish_task_switch+0x413/0xc60 kernel/sched/core.c:5384 Code: 04 00 00 41 c7 84 24 20 0e 00 00 00 00 00 00 e9 db 06 00 00 49 83 c4 48 4c 89 e7 e8 47 e0 53 0a e8 22 2f 3a 00 fb 4c 8b 65 c8 <49> 8d bc 24 18 17 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 RSP: 0018:ffffc90003c477e0 EFLAGS: 00000206 RAX: 000000000001ad27 RBX: ffff8880b873c8e0 RCX: 8000000000000001 RDX: 0000000000000000 RSI: ffffffff8e41727c RDI: ffffffff8c6dad80 RBP: ffffc90003c47830 R08: ffffffff907a667f R09: 1ffffffff20f4ccf R10: dffffc0000000000 R11: fffffbfff20f4cd0 R12: ffff888033593e80 R13: ffff8880b873c8a8 R14: dffffc0000000000 R15: 1ffff110170e791c context_switch kernel/sched/core.c:5536 [inline] __schedule+0x17e3/0x58f0 kernel/sched/core.c:7284 __schedule_loop kernel/sched/core.c:7361 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7376 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 ip_vs_estimation_kthread+0x29ef/0x3950 net/netfilter/ipvs/ip_vs_est.c:216 kthread+0x38b/0x480 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. 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