syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P23195/1:b..l P23192/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=88181, q=85 ncpus=2)
task:syz-executor.4  state:R  running task     stack:25072 pid:23192 tgid:23192 ppid:5081   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5400 [inline]
 __schedule+0x177f/0x4960 kernel/sched/core.c:6727
 preempt_schedule_common+0x83/0xc0 kernel/sched/core.c:6904
 preempt_schedule+0xdd/0xf0 kernel/sched/core.c:6928
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 zap_pte_range mm/memory.c:1549 [inline]
 zap_pmd_range mm/memory.c:1597 [inline]
 zap_pud_range mm/memory.c:1626 [inline]
 zap_p4d_range mm/memory.c:1647 [inline]
 unmap_page_range+0x29be/0x36e0 mm/memory.c:1668
 unmap_vmas+0x3cc/0x5f0 mm/memory.c:1758
 exit_mmap+0x2c6/0xd30 mm/mmap.c:3277
 __mmput+0x115/0x3c0 kernel/fork.c:1343
 exit_mm+0x21f/0x300 kernel/exit.c:569
 do_exit+0x9af/0x2740 kernel/exit.c:858
 do_group_exit+0x206/0x2c0 kernel/exit.c:1020
 __do_sys_exit_group kernel/exit.c:1031 [inline]
 __se_sys_exit_group kernel/exit.c:1029 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1029
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7fa0aa47cda9
RSP: 002b:00007ffc75303458 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 000000000000001e RCX: 00007fa0aa47cda9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000a6a R09: 0000000000000000
R10: 0000001b31020000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
task:modprobe        state:R  running task     stack:23760 pid:23195 tgid:23195 ppid:21475  flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5400 [inline]
 __schedule+0x177f/0x4960 kernel/sched/core.c:6727
 preempt_schedule_irq+0xfb/0x1b0 kernel/sched/core.c:7047
 irqentry_exit+0x5a/0x80 kernel/entry/common.c:348
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:__sanitizer_cov_trace_cmp8+0x7c/0x80 kernel/kcov.c:285
Code: c1 e1 05 48 8d 41 28 4c 39 c8 77 1e 49 ff c2 4c 89 12 48 c7 44 11 08 06 00 00 00 48 89 7c 11 10 48 89 74 11 18 4c 89 44 11 20 <c3> 0f 1f 00 f3 0f 1e fa 4c 8b 04 24 65 48 8b 15 00 c2 74 7e 65 8b
RSP: 0018:ffffc9000325f8f8 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 00007fc356411fff RCX: ffff88808168bb80
RDX: 0000000000000000 RSI: 00007fc356411fff RDI: 00007fc356410fff
RBP: ffffc9000325faf0 R08: ffffffff8b1bec5c R09: ffffffff8b1bea22
R10: 0000000000000004 R11: ffff88808168bb80 R12: 0000000000000001
R13: dffffc0000000000 R14: 000000000000000d R15: 00007fc356410fff
 mas_validate_limits lib/maple_tree.c:7400 [inline]
 mt_validate+0xf8c/0x4a90 lib/maple_tree.c:7502
 validate_mm+0xe7/0x520 mm/mmap.c:288
 do_brk_flags+0xb1f/0x1000 mm/mmap.c:3184
 __do_sys_brk mm/mmap.c:259 [inline]
 __se_sys_brk+0x9c0/0xef0 mm/mmap.c:178
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7fc3564dfc7c
RSP: 002b:00007ffca1052d18 EFLAGS: 00000206 ORIG_RAX: 000000000000000c
RAX: ffffffffffffffda RBX: 0000000000021000 RCX: 00007fc3564dfc7c
RDX: 00007fc3565be1b8 RSI: 00007fc3565b6b00 RDI: 00005640ef304000
RBP: 00007fc3565b6aa0 R08: 0000000000000000 R09: 00007fc3565b6d80
R10: 0000000000000037 R11: 0000000000000206 R12: 00005640ef2e3000
R13: 0000000000000290 R14: 0000000000001000 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10135 jiffies! g88181 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:24656 pid:17    tgid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5400 [inline]
 __schedule+0x177f/0x4960 kernel/sched/core.c:6727
 __schedule_loop kernel/sched/core.c:6802 [inline]
 schedule+0x149/0x260 kernel/sched/core.c:6817
 schedule_timeout+0x1bd/0x300 kernel/time/timer.c:2183
 rcu_gp_fqs_loop+0x30a/0x1500 kernel/rcu/tree.c:1631
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:1830
 kthread+0x2d3/0x370 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
 </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+0x20/0x30 drivers/acpi/processor_idle.c:112