rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P18112 rcu: (detected by 1, t=10503 jiffies, g=82749, q=287 ncpus=2) task:syz.5.4116 state:R running task stack:27016 pid:18112 ppid:16162 flags:0x0000400a Call Trace: sched_show_task+0x481/0x5a0 kernel/sched/core.c:9179 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:261 [inline] print_other_cpu_stall+0xfa7/0x1340 kernel/rcu/tree_stall.h:637 check_cpu_stall kernel/rcu/tree_stall.h:809 [inline] rcu_pending kernel/rcu/tree.c:3950 [inline] rcu_sched_clock_irq+0x87c/0x1220 kernel/rcu/tree.c:2295 update_process_times+0x147/0x1b0 kernel/time/timer.c:2071 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x3a2/0x580 kernel/time/tick-sched.c:1492 __run_hrtimer kernel/time/hrtimer.c:1755 [inline] __hrtimer_run_queues+0x4df/0xc40 kernel/time/hrtimer.c:1819 hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1881 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline] __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0x51/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:variable_ffs arch/x86/include/asm/bitops.h:319 [inline] RIP: 0010:handle_softirqs+0x1b0/0x820 kernel/softirq.c:566 Code: 89 64 24 2c 0f b7 db 48 c7 c7 a0 b1 a9 8a e8 47 19 1d 09 65 66 c7 05 1d 35 b2 7e 00 00 e8 88 74 3a 00 fb 49 c7 c6 c0 a0 a0 8c <89> 5c 24 34 b8 ff ff ff ff 0f bc 44 24 34 41 89 c5 41 ff c5 0f 84 RSP: 0018:ffffc900001f0e40 EFLAGS: 00000286 RAX: de4f7b46fdcf2300 RBX: 0000000000000200 RCX: de4f7b46fdcf2300 RDX: dffffc0000000000 RSI: ffffffff8aaab940 RDI: ffffffff8afc7880 RBP: ffffc900001f0f50 R08: ffffffff90da6537 R09: 1ffffffff21b4ca6 R10: dffffc0000000000 R11: fffffbfff21b4ca7 R12: 000000000000000a R13: 0000000000000000 R14: ffffffff8ca0a0c0 R15: ffff88802330bc00 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline] sysvec_irq_work+0xa1/0xc0 arch/x86/kernel/irq_work.c:17 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723 RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682 Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 19 5e 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b RSP: 0018:ffffc900034e7c00 EFLAGS: 00000206 RAX: de4f7b46fdcf2300 RBX: 1ffff9200069cf88 RCX: de4f7b46fdcf2300 RDX: dffffc0000000000 RSI: ffffffff8aaab940 RDI: ffffffff8afc7880 RBP: ffffc900034e7cf0 R08: ffffffff90da6537 R09: 1ffffffff21b4ca6 R10: dffffc0000000000 R11: fffffbfff21b4ca7 R12: 0000000000000000 R13: dffffc0000000000 R14: 0000000000000246 R15: ffffffff8cd35398 __rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426 rcu_read_unlock+0x85/0xa0 include/linux/rcupdate.h:818 dput+0xe6/0x1e0 fs/dcache.c:911 __fput+0x5e5/0x970 fs/file_table.c:392 task_work_run+0x1ce/0x250 kernel/task_work.c:239 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f302c98e929 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd0b7e1c58 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00000000000c5844 RCX: 00007f302c98e929 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f302cbb7ba0 R08: 0000000000000001 R09: 0000001c0b7e1f4f R10: 00007f302c600000 R11: 0000000000000246 R12: 00007f302cbb5fac R13: 00007f302cbb5fa0 R14: ffffffffffffffff R15: 00007ffd0b7e1d70 rcu: rcu_preempt kthread starved for 10544 jiffies! g82749 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:27400 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x14e2/0x4580 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 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: 18117 Comm: syz.4.4119 Not tainted 6.6.97-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:ring_buffer_unlock_commit+0x5/0x5e0 kernel/trace/ring_buffer.c:3381 Code: ff 84 db 75 0c e8 5b d7 fd ff 5b 41 5e 41 5f 5d c3 e8 4f d7 fd ff e8 fa dc 78 ff eb ed 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 55 <41> 57 41 56 41 55 41 54 53 48 83 ec 30 49 89 fd 49 bc 00 00 00 00 RSP: 0018:ffffc90000007720 EFLAGS: 00000246 RAX: ffffffff81893052 RBX: ffff888017870400 RCX: ffff8880237e9e00 RDX: 0000000000000100 RSI: ffffffff8aaee600 RDI: ffff888017870400 RBP: 0000000000340003 R08: 0000000000000000 R09: 0000000000000002 R10: fffffffffffffff5 R11: 0000000000000100 R12: ffff888018242678 R13: dffffc0000000000 R14: ffffffff8cd7ab20 R15: 0000000000000000 FS: 000055555a73f500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1974771f98 CR3: 0000000066216000 CR4: 00000000003506f0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff1 DR7: 0000000000000600 Call Trace: __buffer_unlock_commit kernel/trace/trace.c:1043 [inline] trace_buffer_unlock_commit_regs+0x5a/0x600 kernel/trace/trace.c:3030 trace_event_buffer_commit+0x22f/0x7e0 kernel/trace/trace.c:3005 do_trace_event_raw_event_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline] trace_event_raw_event_bpf_trace_printk+0x152/0x210 kernel/trace/bpf_trace.h:11 trace_bpf_trace_printk+0x142/0x1a0 kernel/trace/bpf_trace.h:11 ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline] bpf_trace_printk+0x11f/0x190 kernel/trace/bpf_trace.c:371 bpf_prog_9e1c00255e17e72e+0x38/0x3a bpf_dispatcher_nop_func include/linux/bpf.h:1213 [inline] __bpf_prog_run include/linux/filter.h:612 [inline] bpf_prog_run include/linux/filter.h:619 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run1+0x1c9/0x3b0 kernel/trace/bpf_trace.c:2360 __bpf_trace_rcu_utilization+0xa2/0xe0 include/trace/events/rcu.h:27 trace_rcu_utilization+0x179/0x1a0 include/trace/events/rcu.h:27 rcu_core+0x1341/0x1720 kernel/rcu/tree.c:2475 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline] sysvec_irq_work+0xa1/0xc0 arch/x86/kernel/irq_work.c:17 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723 RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682 Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 19 5e 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b RSP: 0018:ffffc900035afc00 EFLAGS: 00000206 RAX: 934b6cbdd4205f00 RBX: 1ffff920006b5f88 RCX: 934b6cbdd4205f00 RDX: dffffc0000000000 RSI: ffffffff8aaab940 RDI: ffffffff8afc7880 RBP: ffffc900035afcf0 R08: ffffffff90da6537 R09: 1ffffffff21b4ca6 R10: dffffc0000000000 R11: fffffbfff21b4ca7 R12: 0000000000000000 R13: dffffc0000000000 R14: 0000000000000246 R15: ffffffff8cd35398 __rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426 rcu_read_unlock+0x85/0xa0 include/linux/rcupdate.h:818 dput+0xe6/0x1e0 fs/dcache.c:911 __fput+0x5e5/0x970 fs/file_table.c:392 task_work_run+0x1ce/0x250 kernel/task_work.c:239 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f0a3698e929 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd9bc400c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00000000000c594b RCX: 00007f0a3698e929 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f0a36bb7ba0 R08: 0000000000000001 R09: 000000189bc403bf R10: 00007f0a36600000 R11: 0000000000000246 R12: 00007f0a36bb5fac R13: 00007f0a36bb5fa0 R14: ffffffffffffffff R15: 00007ffd9bc401e0