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rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (16 ticks this GP) idle=351/1/0x4000000000000000 softirq=44459/44459 fqs=0 (detected by 1, t=10502 jiffies, g=59225, q=1702) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 15122 Comm: syz.4.3616 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:_compound_head include/linux/page-flags.h:196 [inline] RIP: 0010:PageSlab include/linux/page-flags.h:356 [inline] RIP: 0010:kasan_record_aux_stack+0x17/0x100 mm/kasan/generic.c:338 Code: 0f 1f 00 48 89 f2 be f8 00 00 00 e9 23 0e 4c 02 0f 1f 00 41 56 53 48 89 fb e8 a5 eb ff ff 48 85 c0 0f 84 a7 00 00 00 48 89 c7 <48> 8b 40 08 48 89 f9 a8 01 0f 85 99 00 00 00 48 83 39 ff 48 8b 47 RSP: 0018:ffffc90000007010 EFLAGS: 00000086 RAX: ffffea0002e40ec0 RBX: ffff8880b903b1f0 RCX: ffffea0002e40ec8 RDX: ffffea0000000000 RSI: 0000000000000000 RDI: ffffea0002e40ec0 RBP: 0000000000000000 R08: ffff8880b903b1fb R09: 1ffff1101720763f R10: dffffc0000000000 R11: ffffed1017207640 R12: 0000000000000000 R13: dffffc0000000001 R14: 0000000000000000 R15: ffff8880b903b1f8 FS: 00007f528d07e6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c342428 CR3: 00000000543a9000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: <IRQ> irq_work_queue_on+0xf1/0x220 kernel/irq_work.c:101 rcu_read_unlock_special+0x37b/0x4a0 kernel/rcu/tree_plugin.h:667 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] __perf_event_output kernel/events/core.c:7813 [inline] perf_event_output_forward+0x255/0x2e0 kernel/events/core.c:7822 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515 perf_tp_event+0x383/0xbf0 kernel/events/core.c:10047 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674 Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 c2 ef 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08 RSP: 0018:ffffc900000077a0 EFLAGS: 00000206 RAX: 5039e980bf158900 RBX: 1ffff92000000ef8 RCX: 5039e980bf158900 RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f780 RBP: ffffc90000007880 R08: ffffffff901d10cf R09: 1ffffffff203a219 R10: dffffc0000000000 R11: fffffbfff203a21a R12: ffffffff8c322f00 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] netif_receive_skb_list_internal+0x961/0xbd0 net/core/dev.c:5760 gro_normal_list net/core/dev.c:5913 [inline] napi_complete_done+0x378/0x850 net/core/dev.c:6651 virtqueue_napi_complete drivers/net/virtio_net.c:357 [inline] virtnet_poll+0x955/0xf40 drivers/net/virtio_net.c:1624 __napi_poll+0xc0/0x430 net/core/dev.c:7075 napi_poll net/core/dev.c:7142 [inline] net_rx_action+0x4d4/0xa10 net/core/dev.c:7232 handle_softirqs+0x339/0x830 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 common_interrupt+0xb5/0xd0 arch/x86/kernel/irq.c:242 </IRQ> <TASK> asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:667 RIP: 0010:finish_lock_switch+0x134/0x280 kernel/sched/core.c:4804 Code: be ff ff ff ff e8 4c 80 67 08 85 c0 74 4a 4d 85 ff 75 66 0f 1f 44 00 00 48 89 df e8 b6 eb 70 08 e8 41 e0 2a 00 fb 48 83 c4 08 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 48 89 df e8 c9 09 fe ff 43 80 3c RSP: 0018:ffffc9000309ed48 EFLAGS: 00000286 RAX: 5039e980bf158900 RBX: ffff8880b903a340 RCX: 5039e980bf158900 RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f780 RBP: 1ffff11017207613 R08: ffffffff901d10cf R09: 1ffffffff203a219 R10: dffffc0000000000 R11: fffffbfff203a21a R12: 1ffff110172075c1 R13: dffffc0000000000 R14: ffff8880b903ae08 R15: 0000000000000000 finish_task_switch+0x12f/0x640 kernel/sched/core.c:4921 context_switch kernel/sched/core.c:5052 [inline] __schedule+0x11f7/0x43c0 kernel/sched/core.c:6395 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799 irqentry_exit+0x63/0x70 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:fib_create_info+0x1221/0x24f0 net/ipv4/fib_semantics.c:1646 Code: 00 74 6d e8 a1 8d 00 f9 4c 8b 3c 24 4c 89 f8 48 c1 e8 03 80 3c 28 00 74 08 4c 89 ff e8 28 92 45 f9 4d 89 37 41 be ea ff ff ff <48> 8d 7b 44 48 89 f8 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 92 10 00 RSP: 0018:ffffc9000309f128 EFLAGS: 00000287 RAX: ffffffff88788faf RBX: ffff888141f96a00 RCX: 0000000000080000 RDX: ffffc9000ce81000 RSI: 000000000000cf38 RDI: 000000000000cf39 RBP: dffffc0000000000 R08: ffffffff901d10cf R09: 1ffffffff203a219 R10: dffffc0000000000 R11: fffffbfff203a21a R12: ffffc9000309f3a0 R13: ffffc9000309f3a4 R14: 00000000ffffffea R15: 1ffff92000613e74 fib_table_insert+0xe4/0x1bb0 net/ipv4/fib_trie.c:1212 inet_rtm_newroute+0x147/0x230 net/ipv4/fib_frontend.c:905 rtnetlink_rcv_msg+0x844/0xf30 net/core/rtnetlink.c:5684 netlink_rcv_skb+0x1f5/0x440 net/netlink/af_netlink.c:2507 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:706 [inline] __sock_sendmsg net/socket.c:718 [inline] ____sys_sendmsg+0x5b7/0x8f0 net/socket.c:2445 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2499 __sys_sendmsg net/socket.c:2528 [inline] __do_sys_sendmsg net/socket.c:2537 [inline] __se_sys_sendmsg+0x1af/0x290 net/socket.c:2535 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f528ee22eb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f528d07e028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f528f09dfa0 RCX: 00007f528ee22eb9 RDX: 0000000000000000 RSI: 0000200000000000 RDI: 000000000000000b RBP: 00007f528ee90c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f528f09e038 R14: 00007f528f09dfa0 R15: 00007ffcaa9289d8 </TASK> rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g59225 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=22026 rcu: rcu_preempt kthread starved for 10502 jiffies! g59225 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:27184 pid: 15 ppid: 2 flags:0x00004000 Call Trace: <TASK> context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 </TASK> rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 15122 Comm: syz.4.3616 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:__lock_acquire+0xe7/0x7d10 kernel/locking/lockdep.c:4882 Code: 2d 9e 67 a5 7e 48 c7 c0 44 0c 8a 8d 48 c1 e8 03 42 0f b6 04 00 84 c0 0f 85 cb 65 00 00 83 3d 03 04 2d 0c 00 0f 84 a8 27 00 00 <83> 3d 92 d4 c1 0a 00 74 29 48 89 d8 48 c1 e8 03 42 80 3c 00 00 74 RSP: 0018:ffffc90000006c80 EFLAGS: 00000002 RAX: 0000000000000000 RBX: ffffffff8c31eaa0 RCX: 1ffff92000000db4 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8c31eaa0 RBP: ffffc90000006ed0 R08: dffffc0000000000 R09: 0000000000000001 R10: dffffc0000000000 R11: fffffbfff1b13b16 R12: 0000000000000000 R13: ffff88802282bb80 R14: 0000000000000000 R15: 0000000000000001 FS: 00007f528d07e6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c342428 CR3: 00000000543a9000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: <IRQ> lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313 rcu_read_lock include/linux/rcupdate.h:740 [inline] __perf_output_begin kernel/events/ring_buffer.c:163 [inline] perf_output_begin_forward+0xa5/0xa40 kernel/events/ring_buffer.c:271 __perf_event_output kernel/events/core.c:7804 [inline] perf_event_output_forward+0x19b/0x2e0 kernel/events/core.c:7822 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515 perf_tp_event+0x383/0xbf0 kernel/events/core.c:10047 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674 Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 c2 ef 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08 RSP: 0018:ffffc900000077a0 EFLAGS: 00000206 RAX: 5039e980bf158900 RBX: 1ffff92000000ef8 RCX: 5039e980bf158900 RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f780 RBP: ffffc90000007880 R08: ffffffff901d10cf R09: 1ffffffff203a219 R10: dffffc0000000000 R11: fffffbfff203a21a R12: ffffffff8c322f00 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] netif_receive_skb_list_internal+0x961/0xbd0 net/core/dev.c:5760 gro_normal_list net/core/dev.c:5913 [inline] napi_complete_done+0x378/0x850 net/core/dev.c:6651 virtqueue_napi_complete drivers/net/virtio_net.c:357 [inline] virtnet_poll+0x955/0xf40 drivers/net/virtio_net.c:1624 __napi_poll+0xc0/0x430 net/core/dev.c:7075 napi_poll net/core/dev.c:7142 [inline] net_rx_action+0x4d4/0xa10 net/core/dev.c:7232 handle_softirqs+0x339/0x830 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 common_interrupt+0xb5/0xd0 arch/x86/kernel/irq.c:242 </IRQ> <TASK> asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:667 RIP: 0010:finish_lock_switch+0x134/0x280 kernel/sched/core.c:4804 Code: be ff ff ff ff e8 4c 80 67 08 85 c0 74 4a 4d 85 ff 75 66 0f 1f 44 00 00 48 89 df e8 b6 eb 70 08 e8 41 e0 2a 00 fb 48 83 c4 08 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 48 89 df e8 c9 09 fe ff 43 80 3c RSP: 0018:ffffc9000309ed48 EFLAGS: 00000286 RAX: 5039e980bf158900 RBX: ffff8880b903a340 RCX: 5039e980bf158900 RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f780 RBP: 1ffff11017207613 R08: ffffffff901d10cf R09: 1ffffffff203a219 R10: dffffc0000000000 R11: fffffbfff203a21a R12: 1ffff110172075c1 R13: dffffc0000000000 R14: ffff8880b903ae08 R15: 0000000000000000 finish_task_switch+0x12f/0x640 kernel/sched/core.c:4921 context_switch kernel/sched/core.c:5052 [inline] __schedule+0x11f7/0x43c0 kernel/sched/core.c:6395 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799 irqentry_exit+0x63/0x70 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:fib_create_info+0x1221/0x24f0 net/ipv4/fib_semantics.c:1646 Code: 00 74 6d e8 a1 8d 00 f9 4c 8b 3c 24 4c 89 f8 48 c1 e8 03 80 3c 28 00 74 08 4c 89 ff e8 28 92 45 f9 4d 89 37 41 be ea ff ff ff <48> 8d 7b 44 48 89 f8 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 92 10 00 RSP: 0018:ffffc9000309f128 EFLAGS: 00000287 RAX: ffffffff88788faf RBX: ffff888141f96a00 RCX: 0000000000080000 RDX: ffffc9000ce81000 RSI: 000000000000cf38 RDI: 000000000000cf39 RBP: dffffc0000000000 R08: ffffffff901d10cf R09: 1ffffffff203a219 R10: dffffc0000000000 R11: fffffbfff203a21a R12: ffffc9000309f3a0 R13: ffffc9000309f3a4 R14: 00000000ffffffea R15: 1ffff92000613e74 fib_table_insert+0xe4/0x1bb0 net/ipv4/fib_trie.c:1212 inet_rtm_newroute+0x147/0x230 net/ipv4/fib_frontend.c:905 rtnetlink_rcv_msg+0x844/0xf30 net/core/rtnetlink.c:5684 netlink_rcv_skb+0x1f5/0x440 net/netlink/af_netlink.c:2507 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:706 [inline] __sock_sendmsg net/socket.c:718 [inline] ____sys_sendmsg+0x5b7/0x8f0 net/socket.c:2445 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2499 __sys_sendmsg net/socket.c:2528 [inline] __do_sys_sendmsg net/socket.c:2537 [inline] __se_sys_sendmsg+0x1af/0x290 net/socket.c:2535 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f528ee22eb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f528d07e028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f528f09dfa0 RCX: 00007f528ee22eb9 RDX: 0000000000000000 RSI: 0000200000000000 RDI: 000000000000000b RBP: 00007f528ee90c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f528f09e038 R14: 00007f528f09dfa0 R15: 00007ffcaa9289d8 </TASK>
| Time | Kernel | Commit | Syzkaller | Config | Log | Report | Syz repro | C repro | VM info | Assets (help?) | Manager | Title |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026/01/31 20:29 | linux-5.15.y | 9eec9a14ee10 | afc0c4d4 | .config | console log | report | info | [disk image] [vmlinux] [kernel image] | ci2-linux-5-15-kasan-perf | INFO: rcu detected stall in inet_rtm_newroute |