rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5654/1:b..l P8946/1:b..l
	(detected by 1, t=10502 jiffies, g=39897, q=156)
task:syz-executor    state:R  running task     stack:19704 pid: 8946 ppid:  8933 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:676
RIP: 0010:__preempt_count_add kernel/rcu/tree.c:1119 [inline]
RIP: 0010:rcu_is_watching+0x2/0xa0 kernel/rcu/tree.c:1122
Code: 5c 41 5d 41 5e 41 5f 5d c3 e8 fa 15 d4 08 41 f7 c4 00 02 00 00 75 b4 eb b3 e8 da 15 d4 08 66 2e 0f 1f 84 00 00 00 00 00 41 57 <41> 56 53 65 ff 05 3c 36 97 7e e8 7f 29 d4 08 89 c3 83 f8 08 73 72
RSP: 0018:ffffc90003baf8f0 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffff88801c3d9500 RCX: ffff88802aa7bb80
RDX: dffffc0000000000 RSI: ffffffff8af9f2a0 RDI: ffffffff8af9f260
RBP: ffff88802a35b318 R08: dffffc0000000000 R09: fffffbfff2131821
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff8880175e9a00
R13: ffff8880175e9a00 R14: ffffffff814bf3e2 R15: 0000000000000cc0
 rcu_read_unlock include/linux/rcupdate.h:768 [inline]
 percpu_ref_put_many include/linux/percpu-refcount.h:324 [inline]
 percpu_ref_put include/linux/percpu-refcount.h:338 [inline]
 obj_cgroup_put+0x6a/0xc0 include/linux/memcontrol.h:816
 slab_alloc_node mm/slub.c:3220 [inline]
 slab_alloc mm/slub.c:3228 [inline]
 kmem_cache_alloc+0xf3/0x280 mm/slub.c:3233
 vm_area_dup kernel/fork.c:358 [inline]
 dup_mmap kernel/fork.c:557 [inline]
 dup_mm kernel/fork.c:1466 [inline]
 copy_mm+0x8d2/0x1370 kernel/fork.c:1518
 copy_process+0x1816/0x3ef0 kernel/fork.c:2205
 kernel_clone+0x210/0x960 kernel/fork.c:2603
 __do_sys_clone kernel/fork.c:2720 [inline]
 __se_sys_clone kernel/fork.c:2704 [inline]
 __x64_sys_clone+0x23f/0x290 kernel/fork.c:2704
 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: 0033:0x7fd756fc19d3
RSP: 002b:00007ffc9f1bafb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd756fc19d3
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 000055556e2147d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 00000000000683b8 R15: 00007ffc9f1bb150
 </TASK>
task:kworker/u4:8    state:R  running task     stack:21952 pid: 5654 ppid:     2 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
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:676
RIP: 0010:lock_acquire+0x92/0x4f0 kernel/locking/lockdep.c:5591
Code: 81 4c 8d 64 24 40 49 c1 ec 03 48 b8 f1 f1 f1 f1 00 f2 f2 f2 4b 89 04 2c 43 c7 44 2c 09 f2 f2 f2 00 43 c7 44 2c 11 f3 f3 f3 f3 <66> 43 c7 44 2c 15 f3 f3 43 c6 44 2c 17 f3 0f 1f 44 00 00 65 8b 1d
RSP: 0018:ffffc9000300fa80 EFLAGS: 00000a02
RAX: f2f2f200f1f1f1f1 RBX: ffff888062cf1470 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8cb1fce0
RBP: ffffc9000300fbd8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000601f58
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88802afb8780
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312
 rcu_read_lock include/linux/rcupdate.h:739 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
 batadv_nc_worker+0xc1/0x5b0 net/batman-adv/network-coding.c:723
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: rcu_preempt kthread starved for 10545 jiffies! g39897 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:26816 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