syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5491/1:b..l P75/1:b..l
	(detected by 1, t=10503 jiffies, g=17965, q=3 ncpus=2)
task:kworker/u4:4    state:R  running task     stack:23168 pid:75    ppid:2      flags:0x00004000
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696
RIP: 0010:instrument_atomic_read include/linux/instrumented.h:72 [inline]
RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:444 [inline]
RIP: 0010:cpu_online include/linux/cpumask.h:1030 [inline]
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline]
RIP: 0010:lock_acquire+0xd4/0x490 kernel/locking/lockdep.c:5633
Code: 38 84 c0 0f 85 87 02 00 00 44 3b 35 16 87 bc 0c 0f 83 8c 01 00 00 45 89 f4 41 c1 ee 06 4a 8d 3c f5 28 77 1f 8e be 08 00 00 00 <e8> 87 ff 6d 00 4c 0f a3 25 e7 84 bc 0c 73 0d e8 f8 1b 08 00 84 c0
RSP: 0018:ffffc900020cf920 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e1f7728
RBP: ffffc900020cfa28 R08: 0000000000000000 R09: 0000000000000000
R10: fffffbfff1c3eee6 R11: 1ffffffff1c3eee5 R12: 0000000000000000
R13: 1ffff92000419f30 R14: 0000000000000000 R15: dffffc0000000000
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:754 [inline]
 batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:825 [inline]
 batadv_iv_ogm_schedule+0x413/0xe90 net/batman-adv/bat_iv_ogm.c:868
 batadv_iv_send_outstanding_bat_ogm_packet+0x72d/0x840 net/batman-adv/bat_iv_ogm.c:1712
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
task:syz.3.291       state:R  running task     stack:25216 pid:5491  ppid:4278   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696
RIP: 0010:mas_validate_gaps lib/maple_tree.c:6981 [inline]
RIP: 0010:mt_validate+0x2e9e/0x4c90 lib/maple_tree.c:7244
Code: f7 85 db 4c 8b 74 24 18 74 78 e8 dd a7 7b f7 48 8b 5c 24 30 48 83 7c 24 68 00 0f 85 70 fb ff ff e8 c7 a7 7b f7 48 2b 5c 24 40 <4a> 8d 5c 23 01 48 8b 44 24 28 48 39 c3 48 0f 47 c3 48 89 44 24 28
RSP: 0018:ffffc900032876e0 EFLAGS: 00000287
RAX: ffffffff8a052729 RBX: ffff8065c92e2000 RCX: ffff888027198000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900032878b0 R08: ffff888027198000 R09: 0000000000000004
R10: 0000000000000003 R11: 0000000000000000 R12: 00007f9a36eb9fff
R13: ffffffff8bb15ba1 R14: 0000000000000001 R15: 0000000000000005
 validate_mm_mt+0xcd/0x420 mm/mmap.c:295
 validate_mm+0xcc/0x2b0 mm/mmap.c:332
 mmap_region+0x780/0x1c70 mm/mmap.c:2922
 do_mmap+0x958/0xfd0 mm/mmap.c:1436
 vm_mmap_pgoff+0x1b2/0x2b0 mm/util.c:520
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9a35f8ef03
RSP: 002b:00007ffcf6e002f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f9a349f76c0 RCX: 00007f9a35f8ef03
RDX: 0000000000000000 RSI: 0000000000021000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 00000000ffffffff R09: 0000000000000000
R10: 0000000000020022 R11: 0000000000000246 R12: 00007ffcf6e00450
R13: ffffffffffffffc0 R14: 0000000000001000 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10559 jiffies! g17965 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:27432 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4282 Comm: kworker/u5:5 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: hci5 hci_power_on
RIP: 0010:__preempt_count_add kernel/rcu/tree.c:717 [inline]
RIP: 0010:rcu_is_watching+0x0/0xa0 kernel/rcu/tree.c:720
Code: ff ff eb 99 e8 01 55 ac 08 48 c7 c7 e0 16 b3 8c 4c 89 f6 e8 92 86 c3 02 e9 53 ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 <41> 57 41 56 53 65 ff 05 fc 60 97 7e e8 7f 69 ac 08 89 c3 83 f8 08
RSP: 0018:ffffc90000007ce8 EFLAGS: 00000002
RAX: ffffffff81712869 RBX: 0000000000000001 RCX: 0000000000010000
RDX: ffff88802e47d940 RSI: 0000000000000001 RDI: 0000000000000002
RBP: 0000000000000002 R08: dffffc0000000000 R09: fffffbfff1c3eee6
R10: fffffbfff1c3eee6 R11: 1ffffffff1c3eee5 R12: ffff8880b8e2aec0
R13: dffffc0000000000 R14: 0000000000000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f370f3c35f0 CR3: 0000000077545000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 trace_hrtimer_cancel include/trace/events/timer.h:297 [inline]
 debug_deactivate+0xa2/0x240 kernel/time/hrtimer.c:510
 __run_hrtimer kernel/time/hrtimer.c:1715 [inline]
 __hrtimer_run_queues+0x2df/0xd60 kernel/time/hrtimer.c:1811
 hrtimer_interrupt+0x3c5/0x9c0 kernel/time/hrtimer.c:1873
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
 __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:console_trylock_spinning kernel/printk/printk.c:1948 [inline]
RIP: 0010:vprintk_emit+0x461/0x680 kernel/printk/printk.c:2302
Code: 85 8f 01 00 00 e8 ff b8 1a 00 41 89 df 4d 85 f6 48 8b 1c 24 75 07 e8 ee b8 1a 00 eb 06 e8 e7 b8 1a 00 fb 48 c7 c7 80 ee b1 8c <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 37 db
RSP: 0018:ffffc900041c7660 EFLAGS: 00000293
RAX: ffffffff81661609 RBX: ffffffff816614b5 RCX: ffff88802e47d940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8cb1ee80
RBP: ffffc900041c7750 R08: dffffc0000000000 R09: fffffbfff215c463
R10: fffffbfff215c463 R11: 1ffffffff215c462 R12: dffffc0000000000
R13: 1ffff92000838ed0 R14: 0000000000000200 R15: 000000000000002b
 _printk+0xcc/0x110 kernel/printk/printk.c:2328
 bt_err+0x108/0x150 net/bluetooth/lib.c:251
 __hci_cmd_sync_status_sk net/bluetooth/hci_sync.c:261 [inline]
 __hci_cmd_sync_status net/bluetooth/hci_sync.c:277 [inline]
 hci_reset_sync+0x110/0x130 net/bluetooth/hci_sync.c:3575
 hci_init1_sync net/bluetooth/hci_sync.c:3710 [inline]
 hci_init_sync net/bluetooth/hci_sync.c:4800 [inline]
 hci_dev_init_sync net/bluetooth/hci_sync.c:4991 [inline]
 hci_dev_open_sync+0x1290/0x3760 net/bluetooth/hci_sync.c:5071
 hci_dev_do_open net/bluetooth/hci_core.c:439 [inline]
 hci_power_on+0x1b1/0x6c0 net/bluetooth/hci_core.c:945
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>