rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8427 rcu: (detected by 0, t=10502 jiffies, g=23533, q=1581 ncpus=2) task:syz.1.927 state:R running task stack:27016 pid:8427 ppid:5782 flags:0x0000400e Call Trace: sched_show_task+0x481/0x5a0 kernel/sched/core.c:9178 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:__sanitizer_cov_trace_pc+0x5c/0x60 kernel/kcov.c:234 Code: f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48 8d 7e 01 8b 89 fc 15 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 0f 1f 00 f3 0f 1e fa 48 8b 04 24 65 48 8b 15 70 2e 7e 7e 65 8b RSP: 0018:ffffc90000007470 EFLAGS: 00000246 RAX: ffffffff818890da RBX: 00000044c2293291 RCX: ffff88802a15da00 RDX: 0000000000000100 RSI: ffffffff8cd79820 RDI: 0000000000000004 RBP: 0000000000000004 R08: ffff88802a15da00 R09: 0000000000000020 R10: 000000000000001f R11: 0000000000000100 R12: ffff88801824259c R13: f800000000000000 R14: 000000000000058c R15: 00000000000b5e84 check_buffer+0x2fa/0x950 kernel/trace/ring_buffer.c:3495 __rb_reserve_next+0x511/0xd50 kernel/trace/ring_buffer.c:3624 rb_reserve_next_event kernel/trace/ring_buffer.c:3759 [inline] ring_buffer_lock_reserve+0xae1/0xed0 kernel/trace/ring_buffer.c:3818 __trace_buffer_lock_reserve kernel/trace/trace.c:992 [inline] trace_event_buffer_lock_reserve+0x1d0/0x6e0 kernel/trace/trace.c:2902 trace_event_buffer_reserve+0x29b/0x3c0 kernel/trace/trace_events.c:661 do_trace_event_raw_event_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline] trace_event_raw_event_bpf_trace_printk+0x101/0x210 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_0605f9f479290f07+0x37/0x3b 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 __traceiter_rcu_utilization+0x70/0xa0 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 39 58 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:ffffc90019217c00 EFLAGS: 00000206 RAX: c1f5b7d59e103c00 RBX: 1ffff92003242f88 RCX: c1f5b7d59e103c00 RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: ffffffff8afc66c0 RBP: ffffc90019217cf0 R08: ffffffff90da3517 R09: 1ffffffff21b46a2 R10: dffffc0000000000 R11: fffffbfff21b46a3 R12: 0000000000000000 R13: dffffc0000000000 R14: 0000000000000246 R15: ffffffff8cd35518 __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: 0033:0x7f7e56f8ebe9 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:00007fff83f94e38 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f7e571b7da0 RCX: 00007f7e56f8ebe9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f7e571b7da0 R08: 0000000000001ad4 R09: 0000000b83f9512f R10: 00007f7e571b7cb0 R11: 0000000000000246 R12: 000000000002e6ec R13: 00007fff83f94f30 R14: ffffffffffffffff R15: 00007fff83f94f50 rcu: rcu_preempt kthread starved for 2609 jiffies! g23533 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:26728 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 schedule+0xbd/0x170 kernel/sched/core.c:6773 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 8481 Comm: syz-executor Not tainted 6.6.102-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:check_region_inline mm/kasan/generic.c:169 [inline] RIP: 0010:kasan_check_range+0x10/0x290 mm/kasan/generic.c:187 Code: c0 c3 0f 0b b8 ea ff ff ff c3 0f 0b b8 ea ff ff ff c3 cc cc cc cc cc cc cc cc 66 0f 1f 00 b0 01 48 85 f6 0f 84 b8 01 00 00 55 <41> 57 41 56 41 55 41 54 53 4c 8d 04 37 49 39 f8 0f 82 5a 02 00 00 RSP: 0018:ffffc900001f05d0 EFLAGS: 00000002 RAX: 0000000000000001 RBX: 0000000000000021 RCX: ffffffff81671640 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90da3500 RBP: ffffc900001f0828 R08: dffffc0000000000 R09: 1ffffffff21b46a0 R10: dffffc0000000000 R11: fffffbfff21b46a1 R12: 0000000058cce5e7 R13: ffff88807e589e00 R14: 00000000c8d5ebdc R15: ffff88807e58a978 FS: 000055556f46f500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa398962700 CR3: 000000003d2fb000 CR4: 00000000003506e0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: instrument_atomic_read include/linux/instrumented.h:68 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] hlock_class kernel/locking/lockdep.c:228 [inline] __lock_acquire+0x1260/0x7c80 kernel/locking/lockdep.c:5134 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] trace_call_bpf+0xe4/0x690 kernel/trace/bpf_trace.c:142 perf_trace_run_bpf_submit+0x7a/0x1c0 kernel/events/core.c:10262 perf_trace_lock_acquire+0x32a/0x3e0 include/trace/events/lock.h:24 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x3e2/0x410 kernel/locking/lockdep.c:5725 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162 class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:522 [inline] try_to_wake_up+0x60/0x1140 kernel/sched/core.c:4232 wakeup_softirqd kernel/softirq.c:80 [inline] handle_softirqs+0x5fe/0x820 kernel/softirq.c:601 __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 39 58 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:ffffc9001969f6c0 EFLAGS: 00000206 RAX: 349b725dff1c7e00 RBX: 1ffff920032d3ee0 RCX: 349b725dff1c7e00 RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: ffffffff8afc66c0 RBP: ffffc9001969f7c0 R08: ffffffff90da359f R09: 1ffffffff21b46b3 R10: dffffc0000000000 R11: fffffbfff21b46b4 R12: 0000000000000000 R13: dffffc0000000000 R14: 0000000000000246 R15: ffffffff8cd35518 __rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426 rcu_read_unlock include/linux/rcupdate.h:818 [inline] d_alloc_parallel+0x119e/0x1480 fs/dcache.c:2733 lookup_open fs/namei.c:3413 [inline] open_last_lookups fs/namei.c:3556 [inline] path_openat+0x907/0x3190 fs/namei.c:3786 do_filp_open+0x1c5/0x3d0 fs/namei.c:3816 do_sys_openat2+0x12c/0x1c0 fs/open.c:1419 do_sys_open fs/open.c:1434 [inline] __do_sys_openat fs/open.c:1450 [inline] __se_sys_openat fs/open.c:1445 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1445 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fa39898d550 Code: 48 89 44 24 20 75 93 44 89 54 24 0c e8 49 94 02 00 44 8b 54 24 0c 89 da 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 89 44 24 0c e8 9c 94 02 00 8b 44 RSP: 002b:00007ffefb6a9910 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000080001 RCX: 00007fa39898d550 RDX: 0000000000080001 RSI: 00007fa398a2c683 RDI: 00000000ffffff9c RBP: 00007fa398a2c683 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000004 R13: 00007ffefb6a99b0 R14: 0000000000000009 R15: 0000000000000000