rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6081/3:b..l rcu: (detected by 0, t=10502 jiffies, g=16401, q=593 ncpus=2) task:syz-executor.0 state:R running task stack:26752 pid:6081 tgid:6081 ppid:5126 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5408 [inline] __schedule+0x17e8/0x4a20 kernel/sched/core.c:6745 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6924 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6948 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] filemap_map_pages+0x1707/0x1e70 mm/filemap.c:3655 do_fault_around mm/memory.c:4884 [inline] do_read_fault mm/memory.c:4917 [inline] do_fault mm/memory.c:5056 [inline] do_pte_missing mm/memory.c:3903 [inline] handle_pte_fault+0x3c13/0x7130 mm/memory.c:5380 __handle_mm_fault mm/memory.c:5523 [inline] handle_mm_fault+0x10df/0x1ba0 mm/memory.c:5688 do_user_addr_fault arch/x86/mm/fault.c:1338 [inline] handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x459/0x8c0 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:0x7f8c9e496ef0 RSP: 002b:00007ffe81ff0648 EFLAGS: 00010216 RAX: 0000000000000020 RBX: 00007ffe81ff0bb0 RCX: 0000000000000000 RDX: 000000000000000a RSI: 00007ffe81ff0b58 RDI: 0000000000000000 RBP: 0000000000000016 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000001 R12: 0000000000000075 R13: 00007ffe81ff0d30 R14: 00007ffe81ff0b58 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10528 jiffies! g16401 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:26448 pid:17 tgid:17 ppid:2 flags:0x00004008 Call Trace: sched_show_task+0x506/0x6d0 kernel/sched/core.c:9191 rcu_check_gp_kthread_starvation+0x1b8/0x310 kernel/rcu/tree_stall.h:549 print_other_cpu_stall+0x1470/0x15a0 kernel/rcu/tree_stall.h:658 check_cpu_stall kernel/rcu/tree_stall.h:799 [inline] rcu_pending kernel/rcu/tree.c:4309 [inline] rcu_sched_clock_irq+0x9f4/0x10a0 kernel/rcu/tree.c:2636 update_process_times+0x1ce/0x230 kernel/time/timer.c:2485 tick_sched_handle kernel/time/tick-sched.c:276 [inline] tick_nohz_handler+0x37c/0x500 kernel/time/tick-sched.c:297 __run_hrtimer kernel/time/hrtimer.c:1687 [inline] __hrtimer_run_queues+0x551/0xd50 kernel/time/hrtimer.c:1751 hrtimer_interrupt+0x396/0x990 kernel/time/hrtimer.c:1813 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline] __sysvec_apic_timer_interrupt+0x110/0x3f0 arch/x86/kernel/apic/apic.c:1049 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:finish_task_switch+0x1ea/0x870 kernel/sched/core.c:5282 Code: c9 50 e8 e9 cb 0b 00 48 83 c4 08 4c 89 f7 e8 cd 38 00 00 0f 1f 44 00 00 4c 89 f7 e8 f0 dc 2e 0a e8 cb fc 36 00 fb 48 8b 5d c0 <48> 8d bb f8 15 00 00 48 89 f8 48 c1 e8 03 49 be 00 00 00 00 00 fc RSP: 0018:ffffc90000167908 EFLAGS: 00000286 RAX: dd007dcca45ff100 RBX: ffff888017ad0000 RCX: ffffffff947ae603 RDX: dffffc0000000000 RSI: ffffffff8bcabaa0 RDI: ffffffff8c1fe6c0 RBP: ffffc90000167950 R08: ffffffff8fad53af R09: 1ffffffff1f5aa75 R10: dffffc0000000000 R11: fffffbfff1f5aa76 R12: 1ffff11017287ea7 R13: dffffc0000000000 R14: ffff8880b943e7c0 R15: ffff8880b943f538 context_switch kernel/sched/core.c:5411 [inline] __schedule+0x17f0/0x4a20 kernel/sched/core.c:6745 __schedule_loop kernel/sched/core.c:6822 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6837 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2581 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2000 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2202 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 17 Comm: rcu_preempt Not tainted 6.9.0-next-20240523-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 RIP: 0010:finish_task_switch+0x1ea/0x870 kernel/sched/core.c:5282 Code: c9 50 e8 e9 cb 0b 00 48 83 c4 08 4c 89 f7 e8 cd 38 00 00 0f 1f 44 00 00 4c 89 f7 e8 f0 dc 2e 0a e8 cb fc 36 00 fb 48 8b 5d c0 <48> 8d bb f8 15 00 00 48 89 f8 48 c1 e8 03 49 be 00 00 00 00 00 fc RSP: 0018:ffffc90000167908 EFLAGS: 00000286 RAX: dd007dcca45ff100 RBX: ffff888017ad0000 RCX: ffffffff947ae603 RDX: dffffc0000000000 RSI: ffffffff8bcabaa0 RDI: ffffffff8c1fe6c0 RBP: ffffc90000167950 R08: ffffffff8fad53af R09: 1ffffffff1f5aa75 R10: dffffc0000000000 R11: fffffbfff1f5aa76 R12: 1ffff11017287ea7 R13: dffffc0000000000 R14: ffff8880b943e7c0 R15: ffff8880b943f538 FS: 0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33225000 CR3: 000000002e3e6000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: context_switch kernel/sched/core.c:5411 [inline] __schedule+0x17f0/0x4a20 kernel/sched/core.c:6745 __schedule_loop kernel/sched/core.c:6822 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6837 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2581 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2000 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2202 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244