syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P49/1:b..l
	(detected by 1, t=10503 jiffies, g=16029, q=513 ncpus=2)
task:kworker/u4:3    state:R  running task     stack:21696 pid:49    ppid:2      flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6558
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870
 irqentry_exit+0x53/0x80 kernel/entry/common.c:439
 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:658
RIP: 0010:lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5666
Code: 2b 00 74 08 4c 89 f7 e8 3f ac 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:ffffc90000ba7a80 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff92000174f5c RCX: 1ffff92000174efc
RDX: dffffc0000000000 RSI: ffffffff8b0c14c0 RDI: ffffffff8b5d7180
RBP: ffffc90000ba7be0 R08: dffffc0000000000 R09: fffffbfff223ba45
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000174f58
R13: dffffc0000000000 R14: ffffc90000ba7ae0 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
 batadv_nc_worker+0xe8/0x610 net/batman-adv/network-coding.c:719
 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:295
 </TASK>
rcu: rcu_preempt kthread starved for 10526 jiffies! g16029 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:26752 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2d2/0x1150 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0xa3/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x28d/0x320 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:
CPU: 1 PID: 5247 Comm: syz.0.409 Not tainted 6.1.112-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:might_alloc include/linux/sched/mm.h:271 [inline]
RIP: 0010:slab_pre_alloc_hook+0x23/0x300 mm/slab.h:710
Code: 00 00 00 00 00 66 90 55 41 57 41 56 41 55 41 54 53 48 83 ec 18 44 89 c5 49 89 cf 49 89 d6 49 89 f4 49 89 fd 23 2d e5 96 b8 0c <89> ef e8 a6 a3 f4 ff 89 ef e8 bf a4 f4 ff f7 c5 00 04 00 00 74 16
RSP: 0018:ffffc900001df748 EFLAGS: 00000202
RAX: ffffffff8894be1e RBX: 00000000000000f0 RCX: 0000000000000001
RDX: ffffc900001df7a8 RSI: 0000000000000000 RDI: ffff88814018e280
RBP: 0000000000000a20 R08: 0000000000000a20 R09: ffffffff863fbcf2
R10: 0000000000000002 R11: ffff888025a05940 R12: 0000000000000000
R13: ffff88814018e280 R14: ffffc900001df7a8 R15: 0000000000000001
FS:  00007f9faa1436c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002000cf3d CR3: 0000000046874000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 slab_alloc_node mm/slub.c:3318 [inline]
 kmem_cache_alloc_node+0x52/0x310 mm/slub.c:3443
 __alloc_skb+0xde/0x670 net/core/skbuff.c:505
 skb_copy+0x127/0x820 net/core/skbuff.c:1732
 mac80211_hwsim_tx_frame_no_nl+0x10f4/0x1a70 drivers/net/wireless/mac80211_hwsim.c:1724
 mac80211_hwsim_tx+0x18d7/0x2600 drivers/net/wireless/mac80211_hwsim.c:1935
 drv_tx net/mac80211/driver-ops.h:35 [inline]
 ieee80211_tx_frags+0x3d8/0x890 net/mac80211/tx.c:1766
 __ieee80211_tx+0x21b/0x4a0 net/mac80211/tx.c:1820
 ieee80211_tx+0x32d/0x460 net/mac80211/tx.c:2000
 __ieee80211_subif_start_xmit+0x10d5/0x33f0 net/mac80211/tx.c:4265
 ieee80211_subif_start_xmit+0xda/0x4c0 net/mac80211/tx.c:4457
 __netdev_start_xmit include/linux/netdevice.h:4853 [inline]
 netdev_start_xmit include/linux/netdevice.h:4867 [inline]
 xmit_one net/core/dev.c:3627 [inline]
 dev_hard_start_xmit+0x261/0x8c0 net/core/dev.c:3643
 sch_direct_xmit+0x2b2/0x5e0 net/sched/sch_generic.c:342
 __dev_xmit_skb net/core/dev.c:3854 [inline]
 __dev_queue_xmit+0x1ace/0x3cf0 net/core/dev.c:4259
 dev_queue_xmit include/linux/netdevice.h:3021 [inline]
 neigh_hh_output include/net/neighbour.h:528 [inline]
 neigh_output include/net/neighbour.h:542 [inline]
 ip6_finish_output2+0xeae/0x15f0 net/ipv6/ip6_output.c:138
 __ip6_finish_output net/ipv6/ip6_output.c:205 [inline]
 ip6_finish_output+0x6a0/0xa80 net/ipv6/ip6_output.c:216
 dst_output include/net/dst.h:444 [inline]
 NF_HOOK include/linux/netfilter.h:302 [inline]
 ndisc_send_skb+0xbab/0x14e0 net/ipv6/ndisc.c:511
 addrconf_rs_timer+0x357/0x610 net/ipv6/addrconf.c:3963
 call_timer_fn+0x1ad/0x6b0 kernel/time/timer.c:1504
 expire_timers kernel/time/timer.c:1549 [inline]
 __run_timers+0x67c/0x890 kernel/time/timer.c:1820
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833
 handle_softirqs+0x2ee/0xa40 kernel/softirq.c:571
 __do_softirq kernel/softirq.c:605 [inline]
 invoke_softirq kernel/softirq.c:445 [inline]
 __irq_exit_rcu+0x157/0x240 kernel/softirq.c:654
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:666
 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1106
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653
RIP: 0010:finish_task_switch+0x1d3/0x810 kernel/sched/core.c:5120
Code: 32 0b 00 48 83 c4 08 4c 89 f7 e8 68 31 00 00 0f 1f 44 00 00 4c 89 f7 e8 9b bd 51 09 e8 26 21 32 00 fb 49 8d bc 24 f8 15 00 00 <48> 89 f8 48 c1 e8 03 49 bd 00 00 00 00 00 fc ff df 42 0f b6 04 28
RSP: 0018:ffffc900032bf8a8 EFLAGS: 00000286
RAX: ab5246e2014ba400 RBX: ffff88801ae60034 RCX: ffffffff97334103
RDX: dffffc0000000000 RSI: ffffffff8b0c0340 RDI: ffff888025a06f38
RBP: ffffc900032bf8f0 R08: ffffffff81b659cc R09: ffffed10171e6ad6
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff888025a05940
R13: 1ffff110171e76e3 R14: ffff8880b8f3a9c0 R15: ffff8880b8f3b718
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x1447/0x4570 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 futex_wait_queue+0x149/0x1d0 kernel/futex/waitwake.c:355
 futex_wait+0x203/0x5c0 kernel/futex/waitwake.c:656
 do_futex+0x3b5/0x490 kernel/futex/syscalls.c:106
 __do_sys_futex kernel/futex/syscalls.c:183 [inline]
 __se_sys_futex+0x3d7/0x460 kernel/futex/syscalls.c:164
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9fa937dff9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9faa1430e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f9fa9535f88 RCX: 00007f9fa937dff9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f9fa9535f88
RBP: 00007f9fa9535f80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9fa9535f8c
R13: 0000000000000000 R14: 00007ffc37dd5470 R15: 00007ffc37dd5558
 </TASK>