rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5755/1:b..l (detected by 0, t=10502 jiffies, g=28481, q=447) task:syz.1.516 state:R running task stack:25304 pid: 5755 ppid: 4903 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5027 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6777 irqentry_exit+0x53/0x80 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x32/0x60 kernel/kcov.c:206 Code: b4 15 82 7e 65 8b 15 b5 15 82 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 34 16 00 00 00 74 2c 8b 91 10 16 00 00 <83> fa 02 75 21 48 8b 91 18 16 00 00 48 8b 32 48 8d 7e 01 8b 89 14 RSP: 0018:ffffc900035d6cf0 EFLAGS: 00000246 RAX: ffffffff818dbc55 RBX: 00007fd80b687ef9 RCX: ffff888070c43b80 RDX: 0000000000000002 RSI: 000000000003ffff RDI: 0000000000040000 RBP: 0000000000233501 R08: ffffc900035d7f58 R09: ffffc900035d6e70 R10: 0000000000000000 R11: dffffc0000000001 R12: ffff888070c43b80 R13: ffffffff816df940 R14: 00007fd80b687ef9 R15: 1ffff920006badb9 rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311 rcu_read_lock include/linux/rcupdate.h:739 [inline] is_bpf_text_address+0x1d/0x260 kernel/bpf/core.c:721 kernel_text_address kernel/extable.c:151 [inline] __kernel_text_address+0x94/0x100 kernel/extable.c:105 unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323 arch_stack_walk+0xf3/0x140 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x113/0x1c0 kernel/stacktrace.c:122 save_stack+0xf6/0x1e0 mm/page_owner.c:119 __set_page_owner+0x37/0x300 mm/page_owner.c:181 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x322a/0x33c0 mm/page_alloc.c:4159 __alloc_pages+0x272/0x700 mm/page_alloc.c:5423 alloc_pages_vma+0x39a/0x800 mm/mempolicy.c:2146 wp_page_copy+0x221/0x2070 mm/memory.c:3021 handle_pte_fault mm/memory.c:4638 [inline] __handle_mm_fault mm/memory.c:4755 [inline] handle_mm_fault+0x2a3d/0x5960 mm/memory.c:4853 do_user_addr_fault arch/x86/mm/fault.c:1357 [inline] handle_page_fault arch/x86/mm/fault.c:1445 [inline] exc_page_fault+0x271/0x700 arch/x86/mm/fault.c:1501 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:568 RIP: 0010:copy_user_enhanced_fast_string+0xe/0x40 arch/x86/lib/copy_user_64.S:206 Code: 89 d1 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 31 c0 0f 01 ca c3 0f 1f 80 00 00 00 00 0f 01 cb 83 fa 40 0f 82 70 ff ff ff 89 d1 a4 31 c0 0f 01 ca c3 66 2e 0f 1f 84 00 00 00 00 00 89 d1 83 f8 RSP: 0018:ffffc900035d7a70 EFLAGS: 00050206 RAX: ffffffff84077e01 RBX: 00000000202d6e80 RCX: 0000000000000e80 RDX: 0000000000001000 RSI: ffff88800f55d180 RDI: 00000000202d6000 RBP: ffffc900035d7cd0 R08: dffffc0000000000 R09: ffffed1001eabc00 R10: 0000000000000000 R11: dffffc0000000001 R12: 00000000202d5e80 R13: 0000000000001000 R14: ffff88800f55d000 R15: 00007ffffffff000 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline] raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline] copyout lib/iov_iter.c:157 [inline] copy_page_to_iter_iovec lib/iov_iter.c:228 [inline] __copy_page_to_iter lib/iov_iter.c:861 [inline] copy_page_to_iter+0x49a/0x10d0 lib/iov_iter.c:889 process_vm_rw_pages mm/process_vm_access.c:45 [inline] process_vm_rw_single_vec mm/process_vm_access.c:117 [inline] process_vm_rw_core mm/process_vm_access.c:215 [inline] process_vm_rw+0x886/0xcc0 mm/process_vm_access.c:283 __do_sys_process_vm_readv mm/process_vm_access.c:295 [inline] __se_sys_process_vm_readv mm/process_vm_access.c:291 [inline] __x64_sys_process_vm_readv+0xdc/0xf0 mm/process_vm_access.c:291 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fd80b687ef9 RSP: 002b:00007fd809b01038 EFLAGS: 00000246 ORIG_RAX: 0000000000000136 RAX: ffffffffffffffda RBX: 00007fd80b840f80 RCX: 00007fd80b687ef9 RDX: 0000000000000002 RSI: 0000000020008400 RDI: 0000000000000064 RBP: 00007fd80b6fa01e R08: 0000000000000286 R09: 0000000000000000 R10: 0000000020008640 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fd80b840f80 R15: 00007ffdaea23cc8 rcu: rcu_preempt kthread starved for 9783 jiffies! g28481 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:27064 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5027 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373 schedule+0x11b/0x1f0 kernel/sched/core.c:6456 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:108 [inline] NMI backtrace for cpu 1 skipped: idling at acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:562