rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P7844/1:b..l P7852/1:b..l
	(detected by 1, t=10502 jiffies, g=30701, q=2)
task:syz.3.1327      state:R  running task     stack:24544 pid: 7852 ppid:  3576 flags:0x00004000
Call Trace:
 <TASK>
 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_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:643
RIP: 0010:__preempt_count_add kernel/rcu/tree.c:1119 [inline]
RIP: 0010:rcu_is_watching+0x0/0xa0 kernel/rcu/tree.c:1122
Code: 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 ba 34 c8 08 41 f7 c4 00 02 00 00 75 b4 eb b3 e8 9a 34 c8 08 66 2e 0f 1f 84 00 00 00 00 00 <41> 57 41 56 53 65 ff 05 ec 56 97 7e e8 3f 48 c8 08 89 c3 83 f8 08
RSP: 0018:ffffc900030175b8 EFLAGS: 00000202
RAX: 0000000000000002 RBX: 0000000000000001 RCX: ffff888024969dc0
RDX: ffff888024969dc0 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90003017690 R08: ffffffff81b91411 R09: fffffbfff1f8e21f
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88807ca44000
R13: dffffc0000000000 R14: 1ffff92000602ebc R15: 0000000000000046
 rcu_read_unlock include/linux/rcupdate.h:768 [inline]
 count_memcg_event_mm+0x31a/0x3e0 include/linux/memcontrol.h:1082
 handle_mm_fault+0x161/0x5950 mm/memory.c:4834
 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 <f3> a4 31 c0 0f 01 ca c3 66 2e 0f 1f 84 00 00 00 00 00 89 d1 83 f8
RSP: 0018:ffffc90003017a70 EFLAGS: 00050206
RAX: ffffffff84074a01 RBX: 00000000201a7e80 RCX: 0000000000000e80
RDX: 0000000000001000 RSI: ffff88800f55b180 RDI: 00000000201a7000
RBP: ffffc90003017cd0 R08: dffffc0000000000 R09: ffffed1001eab800
R10: 0000000000000000 R11: dffffc0000000001 R12: 00000000201a6e80
R13: 0000000000001000 R14: ffff88800f55b000 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: 0033:0x7f203f96ce79
RSP: 002b:00007f203dde9038 EFLAGS: 00000246 ORIG_RAX: 0000000000000136
RAX: ffffffffffffffda RBX: 00007f203fb08f80 RCX: 00007f203f96ce79
RDX: 0000000000000002 RSI: 0000000020008400 RDI: 00000000000002a1
RBP: 00007f203f9da93e R08: 0000000000000286 R09: 0000000000000000
R10: 0000000020008640 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f203fb08f80 R15: 00007ffdd464d838
 </TASK>
task:syz.4.1324      state:R  running task     stack:24472 pid: 7844 ppid:  5716 flags:0x00004000
Call Trace:
 <TASK>
 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:__sanitizer_cov_trace_pc+0x45/0x60 kernel/kcov.c:212
Code: 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 16 00 00 48 39 cf 73 08 48 89 44 f2 08 48 89 3a c3 0f 1f
RSP: 0018:ffffc90002ff72c0 EFLAGS: 00000246
RAX: ffffffff81c39c78 RBX: 0000000000000001 RCX: ffff888023bb8000
RDX: ffffc90010cab000 RSI: 000000000003ffff RDI: 0000000000040000
RBP: ffffea000140b580 R08: ffffffff81c39c66 R09: fffffbfff1f8e219
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffffea000140b580 R14: dffffc0000000000 R15: 00fff00000080001
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 blk_cgroup_congested include/linux/blk-cgroup.h:279 [inline]
 __cgroup_throttle_swaprate+0x98/0x540 mm/swapfile.c:3809
 cgroup_throttle_swaprate include/linux/swap.h:728 [inline]
 shmem_add_to_page_cache+0xd2f/0x17c0 mm/shmem.c:727
 shmem_getpage_gfp+0x1aa1/0x3190 mm/shmem.c:1940
 shmem_fault+0x1d7/0x700 mm/shmem.c:2118
 __do_fault+0x139/0x340 mm/memory.c:3898
 do_read_fault mm/memory.c:4234 [inline]
 do_fault mm/memory.c:4362 [inline]
 handle_pte_fault mm/memory.c:4621 [inline]
 __handle_mm_fault mm/memory.c:4756 [inline]
 handle_mm_fault+0x376f/0x5950 mm/memory.c:4854
 faultin_page mm/gup.c:976 [inline]
 __get_user_pages+0x4ed/0x11d0 mm/gup.c:1197
 populate_vma_page_range+0x215/0x2a0 mm/gup.c:1529
 __mm_populate+0x2a5/0x4a0 mm/gup.c:1638
 mm_populate include/linux/mm.h:2632 [inline]
 vm_mmap_pgoff+0x22b/0x2d0 mm/util.c:556
 ksys_mmap_pgoff+0x13e/0x780 mm/mmap.c:1624
 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: 0033:0x7fe4178cce79
RSP: 002b:00007fe415d49038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fe417a68f80 RCX: 00007fe4178cce79
RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000000020000000
RBP: 00007fe41793a93e R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe417a68f80 R15: 00007ffd2e2c0868
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10574 jiffies! g30701 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=22693
rcu: rcu_preempt kthread starved for 10575 jiffies! g30701 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27040 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 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
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:108 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:562