rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=78173, q=22 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295035420-4295024918), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g78173 f0x2 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:26680 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x142d/0x4550 kernel/sched/core.c:6558 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870 irqentry_exit+0x53/0x80 kernel/entry/common.c:439 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653 RIP: 0010:preempt_count_add+0x30/0x180 kernel/sched/core.c:5703 Code: fb 48 c7 c0 60 41 c9 91 48 c1 e8 03 49 bf 00 00 00 00 00 fc ff df 42 0f b6 04 38 84 c0 0f 85 e2 00 00 00 83 3d e0 ee 6a 10 00 <75> 07 65 8b 05 bf 1c a4 7e 65 01 1d b8 1c a4 7e 48 c7 c0 60 41 c9 RSP: 0018:ffffc90000157b78 EFLAGS: 00000246 RAX: 0000000000000004 RBX: 0000000000000001 RCX: ffffffff91c94103 RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000001 RBP: ffffc90000157cb0 R08: dffffc0000000000 R09: ffffed1027fddb29 R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88813feed940 R13: 1ffff9200002af78 R14: ffff88813feeebb8 R15: dffffc0000000000 schedule+0xb8/0x180 kernel/sched/core.c:6633 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1965 rcu_gp_fqs_loop+0x2d2/0x1150 kernel/rcu/tree.c:1706 rcu_gp_kthread+0xa3/0x3b0 kernel/rcu/tree.c:1905 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 3552 Comm: syz-fuzzer Not tainted 6.1.92-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 RIP: 0010:finish_task_switch+0x1d3/0x810 kernel/sched/core.c:5124 Code: 37 0b 00 48 83 c4 08 4c 89 f7 e8 98 30 00 00 0f 1f 44 00 00 4c 89 f7 e8 7b 20 36 09 e8 36 26 32 00 fb 49 8d bc 24 f8 15 00 00 <48> 89 f8 48 c1 e8 03 49 bd 00 00 00 00 00 fc ff df 42 0f b6 04 28 RSP: 0018:ffffc90003c0f808 EFLAGS: 00000286 RAX: cb650b6577a27000 RBX: ffff8880574d8034 RCX: ffffffff91c94103 RDX: dffffc0000000000 RSI: ffffffff8aec01c0 RDI: ffff8880275495f8 RBP: ffffc90003c0f850 R08: dffffc0000000000 R09: ffffed1017307541 R10: 0000000000000000 R11: dffffc0000000001 R12: ffff888027548000 R13: 1ffff110173076eb R14: ffff8880b983aa00 R15: ffff8880b983b758 FS: 000000c00052e890(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b32c4c000 CR3: 0000000022ba7000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: context_switch kernel/sched/core.c:5248 [inline] __schedule+0x1435/0x4550 kernel/sched/core.c:6558 schedule+0xbf/0x180 kernel/sched/core.c:6634 schedule_hrtimeout_range_clock+0x2a4/0x480 kernel/time/hrtimer.c:2308 ep_poll fs/eventpoll.c:1884 [inline] do_epoll_wait+0x1be9/0x1e60 fs/eventpoll.c:2262 do_epoll_pwait+0x56/0x1d0 fs/eventpoll.c:2296 __do_sys_epoll_pwait fs/eventpoll.c:2309 [inline] __se_sys_epoll_pwait fs/eventpoll.c:2303 [inline] __x64_sys_epoll_pwait+0x2b4/0x300 fs/eventpoll.c:2303 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x40720e Code: 48 83 ec 38 e8 13 00 00 00 48 83 c4 38 5d c3 cc cc cc cc cc cc cc cc cc cc cc cc cc 49 89 f2 48 89 fa 48 89 ce 48 89 df 0f 05 <48> 3d 01 f0 ff ff 76 15 48 f7 d8 48 89 c1 48 c7 c0 ff ff ff ff 48 RSP: 002b:000000c00076d748 EFLAGS: 00000246 ORIG_RAX: 0000000000000119 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000040720e RDX: 0000000000000080 RSI: 000000c00076d818 RDI: 0000000000000004 RBP: 000000c00076d790 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000000003e6 R11: 0000000000000246 R12: 000000c00076d820 R13: 0000000000000010 R14: 000000c00112da00 R15: 000000c00111e9c0