syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5484/1:b..l P26926/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=363145, q=588 ncpus=2)
task:sed             state:R  running task     stack:23680 pid:26926 tgid:26926 ppid:26924  flags:0x00000000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:6851
 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
RIP: 0010:atomic_inc include/linux/atomic/atomic-instrumented.h:435 [inline]
RIP: 0010:mas_validate_gaps lib/maple_tree.c:7371 [inline]
RIP: 0010:mt_validate+0x2ee7/0x4aa0 lib/maple_tree.c:7593
Code: 3f 18 4e f6 4c 8b b4 24 68 01 00 00 48 8b 5c 24 10 48 89 df 4c 89 f6 e8 b7 d7 e6 f5 4c 39 f3 0f 87 26 06 00 00 e8 49 d5 e6 f5 <48> c7 c7 40 20 34 95 be 04 00 00 00 e8 a8 1a 4e f6 f0 ff 05 41 69
RSP: 0018:ffffc900041675a0 EFLAGS: 00000293
RAX: ffffffff8bacb6e7 RBX: 0000000000000000 RCX: ffff888025530000
RDX: 0000000000000000 RSI: 00007faf6fcbdfff RDI: 0000000000000000
RBP: ffffc90004167790 R08: ffffffff8bacb6d9 R09: fffffbfff2a68404
R10: dffffc0000000000 R11: fffffbfff2a68404 R12: 1ffff1100cb8c100
R13: dffffc0000000000 R14: 00007faf6fcbdfff R15: 0000000000000001
 validate_mm+0xe7/0x530 mm/mmap.c:329
 vma_expand+0x802/0xb90 mm/mmap.c:710
 mmap_region+0xb9e/0x2090 mm/mmap.c:2930
 do_mmap+0x8f9/0x1010 mm/mmap.c:1468
 vm_mmap_pgoff+0x1dd/0x3d0 mm/util.c:588
 ksys_mmap_pgoff+0x4f1/0x720 mm/mmap.c:1514
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faf6fda5b74
RSP: 002b:00007ffd81dbdfb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007ffd81dbe030 RCX: 00007faf6fda5b74
RDX: 0000000000000001 RSI: 0000000000025000 RDI: 00007faf6faaf000
RBP: 00007ffd81dbe350 R08: 0000000000000003 R09: 000000000002e000
R10: 0000000000000812 R11: 0000000000000246 R12: 00007faf6fd82570
R13: 00007ffd81dbe3d8 R14: 000000000002d9c6 R15: 0000000000000000
 </TASK>
task:kworker/u8:10   state:R  running task     stack:18576 pid:5484  tgid:5484  ppid:2      flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:6851
 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:rcu_preempt_read_exit kernel/rcu/tree_plugin.h:394 [inline]
RIP: 0010:__rcu_read_unlock+0x34/0x110 kernel/rcu/tree_plugin.h:433
Code: 55 41 54 53 49 bc 00 00 00 00 00 fc ff df 65 4c 8b 34 25 00 d7 03 00 4d 8d ae 44 04 00 00 4c 89 eb 48 c1 eb 03 42 0f b6 04 23 <84> c0 75 6b 41 8b 6d 00 ff cd 42 0f b6 04 23 84 c0 75 76 41 89 6d
RSP: 0018:ffffc900043b7b20 EFLAGS: 00000217
RAX: 0000000000000000 RBX: 1ffff1100430f448 RCX: ffffc900043b7a03
RDX: 0000000000000002 RSI: ffffffff8c0ae6e0 RDI: ffffffff8c606fc0
RBP: 0000000000000000 R08: ffffffff9017f8af R09: 1ffffffff202ff15
R10: dffffc0000000000 R11: fffffbfff202ff16 R12: dffffc0000000000
R13: ffff88802187a244 R14: ffff888021879e00 R15: dffffc0000000000
 rcu_read_unlock include/linux/rcupdate.h:871 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
 batadv_nc_worker+0x290/0x610 net/batman-adv/network-coding.c:719
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xa2e/0x1830 kernel/workqueue.c:3312
 worker_thread+0x86d/0xd10 kernel/workqueue.c:3389
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
rcu: rcu_preempt kthread starved for 10117 jiffies! g363145 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:25232 pid:17    tgid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6621
 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2581
 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2034
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2236
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </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:106 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:111