syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1):
	(detected by 0, t=10502 jiffies, g=354629, q=127)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295140511-4295130009), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10502 jiffies! g354629 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:28864 pid:   14 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:4683 [inline]
 __schedule+0x93a/0x26f0 kernel/sched/core.c:5940
 schedule+0xd3/0x270 kernel/sched/core.c:6019
 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1878
 rcu_gp_fqs_loop kernel/rcu/tree.c:1996 [inline]
 rcu_gp_kthread+0xd34/0x1980 kernel/rcu/tree.c:2169
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 7296 Comm: syz-executor.5 Not tainted 5.14.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:pv_wait_node kernel/locking/qspinlock_paravirt.h:301 [inline]
RIP: 0010:__pv_queued_spin_lock_slowpath+0x5c4/0xb40 kernel/locking/qspinlock.c:473
Code: 32 84 c0 75 23 41 0f b6 14 24 4c 89 e9 83 e1 07 38 ca 7f 08 84 d2 0f 85 ed 03 00 00 0f b6 53 14 84 d2 0f 85 9e 00 00 00 f3 90 <83> e8 01 0f 84 93 00 00 00 0f b6 16 84 d2 74 09 80 fa 03 0f 8e 96
RSP: 0018:ffffc90000dc0a30 EFLAGS: 00000282
RAX: 0000000000002b89 RBX: ffff8880b9c52880 RCX: 0000000000000004
RDX: 0000000000000000 RSI: ffffed10173aa511 RDI: ffff8880b9d52894
RBP: ffff8880b9d52894 R08: 0000000000000001 R09: ffff8880b9d52894
R10: ffffed10173aa512 R11: 0000000000000080 R12: ffffed101738a512
R13: ffff8880b9c52894 R14: dffffc0000000000 R15: ffff8880b9d52880
FS:  00007fb7c410c700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ea1b1b0478 CR3: 000000007cbc5000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
 do_raw_spin_lock+0x200/0x2b0 kernel/locking/spinlock_debug.c:113
 spin_lock include/linux/spinlock.h:354 [inline]
 mac80211_hwsim_tx_frame_no_nl.isra.0+0x68f/0x1330 drivers/net/wireless/mac80211_hwsim.c:1516
 mac80211_hwsim_tx_frame+0x1ee/0x2a0 drivers/net/wireless/mac80211_hwsim.c:1784
 mac80211_hwsim_beacon_tx+0x49b/0x930 drivers/net/wireless/mac80211_hwsim.c:1838
 __iterate_interfaces+0x1e5/0x520 net/mac80211/util.c:793
 ieee80211_iterate_active_interfaces_atomic+0x70/0x180 net/mac80211/util.c:829
 mac80211_hwsim_beacon+0xd5/0x1a0 drivers/net/wireless/mac80211_hwsim.c:1861
 __run_hrtimer kernel/time/hrtimer.c:1537 [inline]
 __hrtimer_run_queues+0x609/0xe50 kernel/time/hrtimer.c:1601
 hrtimer_run_softirq+0x17b/0x360 kernel/time/hrtimer.c:1618
 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558
 invoke_softirq kernel/softirq.c:432 [inline]
 __irq_exit_rcu+0x16e/0x1c0 kernel/softirq.c:636
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648
 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1100
 </IRQ>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:preempt_schedule_irq+0x49/0x90 kernel/sched/core.c:6328
Code: 55 53 65 48 8b 1c 25 00 f0 01 00 48 89 dd 48 c1 ed 03 48 01 c5 bf 01 00 00 00 e8 e2 36 24 f8 e8 2d 7d 50 f8 fb bf 01 00 00 00 <e8> d2 cd ff ff 9c 58 fa f6 c4 02 75 27 bf 01 00 00 00 e8 f0 25 24
RSP: 0018:ffffc90001c1fa08 EFLAGS: 00000206
RAX: 0000000000008aff RBX: ffff8880307c0000 RCX: 1ffffffff1f9b892
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: ffffed10060f8000 R08: 0000000000000001 R09: ffffffff8fccf8c7
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 irqentry_exit+0x31/0x80 kernel/entry/common.c:427
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:batadv_check_known_mac_addr+0xcb/0x400 net/batman-adv/hard-interface.c:503
Code: df 49 89 c6 48 89 44 24 08 49 c1 ee 03 4b 8d 04 26 48 89 04 24 e8 05 39 af f8 48 8d 7b 10 48 89 f8 48 c1 e8 03 42 0f b6 04 20 <84> c0 74 06 0f 8e 72 02 00 00 0f b6 43 10 bf 01 00 00 00 8d 68 fd
RSP: 0018:ffffc90001c1fad8 EFLAGS: 00000a02
RAX: 0000000000000000 RBX: ffff888039e26000 RCX: ffffc90014bf6000
RDX: 0000000000040000 RSI: ffffffff88c64ebb RDI: ffff888039e26010
RBP: 00000000fffffffd R08: 0000000000000000 R09: 00000000fffffffd
R10: ffffffff88c64ee8 R11: 0000000000000001 R12: dffffc0000000000
R13: ffff88808bf8c000 R14: ffff88802df36000 R15: ffff888035124c10
 batadv_hardif_add_interface net/batman-adv/hard-interface.c:877 [inline]
 batadv_hard_if_event+0xfbf/0x15b0 net/batman-adv/hard-interface.c:941
 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2123
 call_netdevice_notifiers_extack net/core/dev.c:2135 [inline]
 call_netdevice_notifiers net/core/dev.c:2149 [inline]
 register_netdevice+0x106b/0x1500 net/core/dev.c:10380
 register_netdev+0x2d/0x50 net/core/dev.c:10473
 br_add_bridge+0x97/0xf0 net/bridge/br_if.c:459
 br_ioctl_deviceless_stub+0x6e6/0x780 net/bridge/br_ioctl.c:373
 sock_ioctl+0x3e8/0x6a0 net/socket.c:1179
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:1069 [inline]
 __se_sys_ioctl fs/ioctl.c:1055 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665e9
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb7c410c188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665e9
RDX: 0000000020000000 RSI: 00000000000089a0 RDI: 0000000000000004
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 00007ffecc52efcf R14: 00007fb7c410c300 R15: 0000000000022000