rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P3996/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=276129, q=56 ncpus=2)
task:syz-executor.0  state:R  running task     stack:27064 pid:3996  ppid:5071   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0xee1/0x59f0 kernel/sched/core.c:6695
 preempt_schedule_irq+0x52/0x90 kernel/sched/core.c:7007
 irqentry_exit+0x35/0x80 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645
RIP: 0010:__sanitizer_cov_trace_pc+0x3b/0x70 kernel/kcov.c:207
Code: 81 e1 00 01 00 00 65 48 8b 14 25 00 bd 03 00 a9 00 01 ff 00 74 0e 85 c9 74 35 8b 82 04 16 00 00 85 c0 74 2b 8b 82 e0 15 00 00 <83> f8 02 75 20 48 8b 8a e8 15 00 00 8b 92 e4 15 00 00 48 8b 01 48
RSP: 0018:ffffc90014c57500 EFLAGS: 00000246
RAX: 0000000000000002 RBX: 0000000040256867 RCX: 0000000000000000
RDX: ffff888081ca41c0 RSI: ffffffff81c60636 RDI: 0000000000000001
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffed100ed22ae4
R10: ffff888076915723 R11: dffffc0000000000 R12: ffff88807a56cde8
R13: ffffc90014c576b8 R14: 0000000000000000 R15: ffffc90014c575a8
 rcu_read_unlock+0x6/0xc0 include/linux/rcupdate.h:778
 pte_unmap include/linux/pgtable.h:113 [inline]
 wp_page_copy mm/memory.c:3182 [inline]
 do_wp_page+0x1857/0x34c0 mm/memory.c:3449
 handle_pte_fault mm/memory.c:4994 [inline]
 __handle_mm_fault+0x1d20/0x3e20 mm/memory.c:5119
 handle_mm_fault+0x47a/0xa00 mm/memory.c:5284
 do_user_addr_fault+0x3d1/0x1010 arch/x86/mm/fault.c:1413
 handle_page_fault arch/x86/mm/fault.c:1505 [inline]
 exc_page_fault+0x5c/0xd0 arch/x86/mm/fault.c:1561
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
RIP: 0010:rep_movs_alternative+0x4a/0x70 arch/x86/lib/copy_user_64.S:71
Code: 75 f1 c3 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 df 83 f9 08 73 e8 eb c9 <f3> a4 c3 48 89 c8 48 c1 e9 03 83 e0 07 f3 48 a5 89 c1 85 c9 75 b3
RSP: 0018:ffffc90014c57920 EFLAGS: 00050206
RAX: 0000000000000001 RBX: 0000000000001000 RCX: 0000000000000e80
RDX: 0000000000000000 RSI: ffff8880105e2180 RDI: 0000000020dbd000
RBP: 0000000020dbce80 R08: 0000000000000000 R09: ffffed10020bc5ff
R10: ffff8880105e2fff R11: 0000000000000000 R12: ffff8880105e2000
R13: 0000000020dbde80 R14: 0000000000000000 R15: ffffc90014c57d68
 copy_user_generic arch/x86/include/asm/uaccess_64.h:112 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:133 [inline]
 copyout.part.0+0x68/0x80 lib/iov_iter.c:168
 copyout lib/iov_iter.c:316 [inline]
 _copy_to_iter+0x4cd/0x1230 lib/iov_iter.c:316
 copy_page_to_iter lib/iov_iter.c:481 [inline]
 copy_page_to_iter+0xf1/0x180 lib/iov_iter.c:468
 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.constprop.0+0x5cd/0xa20 mm/process_vm_access.c:215
 process_vm_rw+0x2ff/0x360 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+0xe2/0x1b0 mm/process_vm_access.c:291
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fad7787cae9
RSP: 002b:00007fad786110c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000136
RAX: ffffffffffffffda RBX: 00007fad7799c050 RCX: 00007fad7787cae9
RDX: 0000000000000002 RSI: 0000000020008400 RDI: 00000000000013d3
RBP: 00007fad778c847a R08: 0000000000000286 R09: 0000000000000000
R10: 0000000020008640 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007fad7799c050 R15: 00007ffd2f3c0ed8
 </TASK>
rcu: rcu_preempt kthread starved for 10320 jiffies! g276129 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:28704 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0xee1/0x59f0 kernel/sched/core.c:6695
 schedule+0xe7/0x1b0 kernel/sched/core.c:6771
 schedule_timeout+0x157/0x2c0 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x1ec/0xa50 kernel/rcu/tree.c:1613
 rcu_gp_kthread+0x249/0x380 kernel/rcu/tree.c:1812
 kthread+0x33a/0x430 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 </TASK>
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:48 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:86 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt+0x1b/0x20 drivers/acpi/processor_idle.c:112