syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P3709/1:b..l P21897/1:b..l
	(detected by 0, t=10504 jiffies, g=116029, q=552 ncpus=2)
task:kworker/u4:6    state:R  running task     stack:24680 pid:21897 ppid:2      flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6554
 preempt_schedule_notrace+0xf8/0x140 kernel/sched/core.c:6816
 preempt_schedule_notrace_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35
 rcu_is_watching+0x76/0xb0 kernel/rcu/tree.c:721
 rcu_read_unlock include/linux/rcupdate.h:776 [inline]
 inet_twsk_purge+0xa3e/0xb60 net/ipv4/inet_timewait_sock.c:339
 ops_exit_list net/core/net_namespace.c:174 [inline]
 cleanup_net+0x763/0xb60 net/core/net_namespace.c:601
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>
task:kworker/u4:12   state:R  running task     stack:22272 pid:3709  ppid:2      flags:0x00004000
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6554
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6866
 irqentry_exit+0x53/0x80 kernel/entry/common.c:433
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5665
Code: 2b 00 74 08 4c 89 f7 e8 1f 6d 77 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc9000458f900 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff920008b1f2c RCX: 1ffff920008b1ecc
RDX: dffffc0000000000 RSI: ffffffff8aebf420 RDI: ffffffff8b3cef00
RBP: ffffc9000458fa48 R08: dffffc0000000000 R09: fffffbfff2091845
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920008b1f28
R13: dffffc0000000000 R14: ffffc9000458f960 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:306 [inline]
 rcu_read_lock include/linux/rcupdate.h:747 [inline]
 batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:755 [inline]
 batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:826 [inline]
 batadv_iv_ogm_schedule+0x43b/0x1090 net/batman-adv/bat_iv_ogm.c:869
 batadv_iv_send_outstanding_bat_ogm_packet+0x6fa/0x800 net/batman-adv/bat_iv_ogm.c:1713
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>
rcu: rcu_preempt kthread starved for 10490 jiffies! g116029 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:25528 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6554
 schedule+0xbf/0x180 kernel/sched/core.c:6630
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1935
 rcu_gp_fqs_loop+0x2c2/0x1010 kernel/rcu/tree.c:1661
 rcu_gp_kthread+0xa3/0x3a0 kernel/rcu/tree.c:1860
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 7680 Comm: kworker/u4:20 Not tainted 6.1.60-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:413 [inline]
RIP: 0010:smp_call_function_many_cond+0x1f67/0x33d0 kernel/smp.c:987
Code: e6 01 31 ff e8 6a 42 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 0a e8 f5 3e 0b 00 e9 1b ff ff ff f3 90 42 0f b6 04 2b <84> c0 75 14 41 f7 07 01 00 00 00 0f 84 fe fe ff ff e8 d3 3e 0b 00
RSP: 0018:ffffc9001558f5a0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 1ffff11017328031 RCX: ffff88807cf43b80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9001558f980 R08: ffffffff817f3f66 R09: fffffbfff2091845
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000800000000
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8880b9940188
FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005646684e0968 CR3: 000000000ce8e000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1155
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:1329 [inline]
 text_poke_bp_batch+0x2bb/0x940 arch/x86/kernel/alternative.c:1529
 text_poke_flush arch/x86/kernel/alternative.c:1720 [inline]
 text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1727
 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x12e/0x250 kernel/jump_label.c:177
 static_key_enable+0x16/0x20 kernel/jump_label.c:190
 toggle_allocation_gate+0xbf/0x480 mm/kfence/core.c:804
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>