rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4402/1:b..l
	(detected by 1, t=10502 jiffies, g=8617, q=576 ncpus=2)
task:syz.2.7         state:R  running task     stack:25072 pid:4402  ppid:4271   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__sanitizer_cov_trace_pc+0x41/0x60 kernel/kcov.c:221
Code: ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c 8b 91 f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 <48> 8d 7e 01 8b 89 fc 15 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2
RSP: 0018:ffffc90004b5f240 EFLAGS: 00000246
RAX: ffffffff8a04effb RBX: 0000000000000300 RCX: ffff88807d9c1dc0
RDX: ffffc9000e241000 RSI: 0000000000017912 RDI: 0000000000000300
RBP: ffff88807787200c R08: ffff88807d9c1dc0 R09: 0000000000000003
R10: 0000000000000003 R11: 0000000000000002 R12: 0000000000000000
R13: 00007f925e1f7fff R14: ffff888077e51e00 R15: 0000000000000000
 mt_locked lib/maple_tree.c:807 [inline]
 mt_slot lib/maple_tree.c:814 [inline]
 mtree_range_walk+0x49b/0x7b0 lib/maple_tree.c:2986
 mas_state_walk lib/maple_tree.c:3901 [inline]
 mt_find+0x230/0x810 lib/maple_tree.c:6537
 find_vma+0x126/0x1a0 mm/mmap.c:1898
 lock_mm_and_find_vma+0x71/0x2f0 mm/memory.c:5387
 do_user_addr_fault+0x2db/0xb10 arch/x86/mm/fault.c:1312
 handle_page_fault arch/x86/mm/fault.c:1431 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1487
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0010:copy_user_enhanced_fast_string+0xa/0x40 arch/x86/lib/copy_user_64.S:166
Code: ff c9 75 f2 89 d1 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 31 c0 0f 01 ca c3 8d 0c ca 89 ca eb 20 0f 01 cb 83 fa 40 72 38 89 d1 <f3> a4 31 c0 0f 01 ca c3 89 ca eb 0a 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90004b5f6a8 EFLAGS: 00050206
RAX: ffffffff84051801 RBX: 0000000000001000 RCX: 0000000000000608
RDX: 0000000000001000 RSI: 0000200000212000 RDI: ffff88805391a9f8
RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed100a723600
R10: 0000000000000000 R11: 0000000000000200 R12: 00007fffffffe000
R13: 0000000000211588 R14: ffff88805391a000 R15: 0000200000211608
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_from_user arch/x86/include/asm/uaccess_64.h:52 [inline]
 copyin+0xe7/0x120 lib/iov_iter.c:183
 _copy_from_iter+0x45a/0x10c0 lib/iov_iter.c:631
 copy_page_from_iter+0x77/0x100 lib/iov_iter.c:752
 mptcp_sendmsg+0xb11/0x1730 net/mptcp/protocol.c:1895
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x59b/0x970 net/socket.c:2519
 ___sys_sendmsg+0x21c/0x290 net/socket.c:2573
 __sys_sendmsg net/socket.c:2602 [inline]
 __do_sys_sendmsg net/socket.c:2611 [inline]
 __se_sys_sendmsg+0x19e/0x270 net/socket.c:2609
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f925f78f749
RSP: 002b:00007f9260574038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f925f9e5fa0 RCX: 00007f925f78f749
RDX: 0000000000000000 RSI: 0000200000000080 RDI: 0000000000000006
RBP: 00007f925f813f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f925f9e6038 R14: 00007f925f9e5fa0 R15: 00007ffc4722ad38
 </TASK>
rcu: rcu_preempt kthread starved for 9311 jiffies! g8617 f0x0 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:26880 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </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 default_idle+0xb/0x10 arch/x86/kernel/process.c:741