rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 1, t=10502 jiffies, g=5077, q=32) rcu: All QSes seen, last rcu_preempt kthread activity 3349 (4295002251-4294998902), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 3350 jiffies! g5077 f0x2 RCU_GP_CLEANUP(7) ->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:26576 pid: 14 ppid: 2 flags:0x00004000 Call Trace: <TASK> context_switch kernel/sched/core.c:4972 [inline] __schedule+0xb72/0x1460 kernel/sched/core.c:6253 preempt_schedule_common kernel/sched/core.c:6419 [inline] preempt_schedule+0x14d/0x190 kernel/sched/core.c:6444 preempt_schedule_thunk+0x16/0x18 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irq+0x3c/0x40 kernel/locking/spinlock.c:202 rcu_gp_cleanup+0x4f4/0xbc0 kernel/rcu/tree.c:2059 rcu_gp_kthread+0xb3/0x350 kernel/rcu/tree.c:2132 kthread+0x468/0x490 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 </TASK> rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 3645 Comm: syz-executor587 Not tainted 5.16.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1dc/0x2d8 lib/dump_stack.c:106 nmi_cpu_backtrace+0x45f/0x490 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation+0x1ff/0x270 kernel/rcu/tree_stall.h:481 print_other_cpu_stall kernel/rcu/tree_stall.h:586 [inline] check_cpu_stall kernel/rcu/tree_stall.h:729 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq+0x23d5/0x2bc0 kernel/rcu/tree.c:2597 update_process_times+0x197/0x200 kernel/time/timer.c:1785 tick_sched_handle kernel/time/tick-sched.c:226 [inline] tick_sched_timer+0x27d/0x420 kernel/time/tick-sched.c:1428 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4cb/0xa60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:unwind_next_frame+0xaa1/0x1fc0 Code: 42 8a 04 30 84 c0 48 8b 5c 24 78 48 8b 6c 24 20 0f 85 e1 11 00 00 c6 03 00 ba 10 00 00 00 48 8b 7c 24 28 31 f6 e8 af b0 95 00 <e9> 66 04 00 00 48 89 5c 24 60 49 8d 7d 08 48 89 f8 48 c1 e8 03 42 RSP: 0018:ffffc900027de900 EFLAGS: 00000202 RAX: ffffc900027dea10 RBX: ffffc900027de9f5 RCX: 0000000000000000 RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc900027dea20 RBP: ffffffff8e814392 R08: dffffc0000000000 R09: ffffc900027dea10 R10: fffff520004fbd44 R11: 0000000000000000 R12: 1ffffffff1d02872 R13: ffffc900027de9c0 R14: dffffc0000000000 R15: ffffffff8e814396 arch_stack_walk+0x112/0x140 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x11b/0x1e0 kernel/stacktrace.c:122 save_stack+0xff/0x200 mm/page_owner.c:119 __set_page_owner+0x42/0x2f0 mm/page_owner.c:181 prep_new_page mm/page_alloc.c:2418 [inline] get_page_from_freelist+0x729/0x9e0 mm/page_alloc.c:4149 __alloc_pages+0x255/0x580 mm/page_alloc.c:5369 alloc_slab_page mm/slub.c:1793 [inline] allocate_slab+0xcc/0x4d0 mm/slub.c:1930 new_slab mm/slub.c:1993 [inline] ___slab_alloc+0x41e/0xc40 mm/slub.c:3022 __slab_alloc mm/slub.c:3109 [inline] slab_alloc_node mm/slub.c:3200 [inline] slab_alloc mm/slub.c:3242 [inline] kmem_cache_alloc+0x276/0x310 mm/slub.c:3247 kmem_cache_zalloc include/linux/slab.h:714 [inline] alloc_buffer_head+0x20/0xf0 fs/buffer.c:3309 alloc_page_buffers+0x309/0x5a0 fs/buffer.c:832 create_empty_buffers+0x36/0x640 fs/buffer.c:1560 ext4_block_write_begin+0x300/0x1840 fs/ext4/inode.c:1060 ext4_da_write_begin+0x58c/0x9b0 fs/ext4/inode.c:2966 generic_perform_write+0x2dd/0x600 mm/filemap.c:3754 ext4_buffered_write_iter+0x391/0x520 fs/ext4/file.c:269 ext4_file_write_iter+0x8f7/0x1bd0 do_iter_readv_writev+0x54f/0x740 do_iter_write+0x21e/0x7b0 fs/read_write.c:851 iter_file_splice_write+0x7eb/0xfa0 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0xe6/0x1c0 fs/splice.c:936 splice_direct_to_actor+0x529/0xd00 fs/splice.c:891 do_splice_direct+0x291/0x3e0 fs/splice.c:979 do_sendfile+0x6fe/0x1040 fs/read_write.c:1245 __do_sys_sendfile64 fs/read_write.c:1310 [inline] __se_sys_sendfile64+0x171/0x1d0 fs/read_write.c:1296 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f364932b0a9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 00 00 90 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 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd55ee2f98 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 00007f364932b0a9 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000004 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001 R10: 00008400fffffffa R11: 0000000000000246 R12: 00007f36492ee880 R13: 0000000000000000 R14: 00007ffd55ee2fc0 R15: 00007ffd55ee2fb0 </TASK> sched: RT throttling activated ---------------- Code disassembly (best guess): 0: 42 8a 04 30 mov (%rax,%r14,1),%al 4: 84 c0 test %al,%al 6: 48 8b 5c 24 78 mov 0x78(%rsp),%rbx b: 48 8b 6c 24 20 mov 0x20(%rsp),%rbp 10: 0f 85 e1 11 00 00 jne 0x11f7 16: c6 03 00 movb $0x0,(%rbx) 19: ba 10 00 00 00 mov $0x10,%edx 1e: 48 8b 7c 24 28 mov 0x28(%rsp),%rdi 23: 31 f6 xor %esi,%esi 25: e8 af b0 95 00 callq 0x95b0d9 * 2a: e9 66 04 00 00 jmpq 0x495 <-- trapping instruction 2f: 48 89 5c 24 60 mov %rbx,0x60(%rsp) 34: 49 8d 7d 08 lea 0x8(%r13),%rdi 38: 48 89 f8 mov %rdi,%rax 3b: 48 c1 e8 03 shr $0x3,%rax 3f: 42 rex.X