rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P48/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=10893, q=577 ncpus=2)
task:kworker/u4:3    state:R  running task     stack:25000 pid:48    ppid:2      flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7011
 irqentry_exit+0x67/0x70 kernel/entry/common.c:441
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:debug_lockdep_rcu_enabled+0x20/0x30 kernel/rcu/update.c:320
Code: cc cc cc cc cc cc cc cc cc cc f3 0f 1e fa 31 c0 83 3d 9f 4a d9 04 00 74 1d 83 3d 16 7e d9 04 00 74 14 65 48 8b 0d 60 a6 70 75 <31> c0 83 b9 e4 0a 00 00 00 0f 94 c0 c3 cc cc cc 66 0f 1f 00 48 8b
RSP: 0018:ffffc90000b8fb58 EFLAGS: 00000202
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88801b288000
RDX: 0000000000000000 RSI: ffffffff8b1d5140 RDI: ffffffff8b1d5100
RBP: 0000000000000000 R08: dffffc0000000000 R09: 1ffffffff23fe2a0
R10: dffffc0000000000 R11: fffffbfff23fe2a1 R12: dffffc0000000000
R13: ffffffff8a5a1712 R14: ffff88802636cd00 R15: 00000000000002fb
 rcu_read_unlock include/linux/rcupdate.h:815 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
 batadv_nc_worker+0x1ee/0x600 net/batman-adv/network-coding.c:719
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: rcu_preempt kthread starved for 10525 jiffies! g10893 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:27848 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </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: 5834 Comm: kworker/u5:2 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Workqueue: hci2 hci_cmd_timeout
RIP: 0010:__rcu_read_unlock+0x55/0xd0 kernel/rcu/tree_plugin.h:425
Code: ec 03 43 0f b6 04 3c 84 c0 75 48 ff 0b 75 1d 4c 8d b7 40 04 00 00 4c 89 f0 48 c1 e8 03 42 0f b6 04 38 84 c0 75 5f 41 83 3e 00 <75> 20 43 0f b6 04 3c 84 c0 75 3a 8b 03 3d 00 00 00 40 73 0a 5b 41
RSP: 0018:ffffc90000007c68 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff88807b8c223c RCX: ffff88807b8c1e00
RDX: 0000000000010000 RSI: ffffffff8b1d5140 RDI: ffff88807b8c1e00
RBP: ffff88807db8ac58 R08: ffff8880278040c3 R09: 1ffff11004f00818
R10: dffffc0000000000 R11: ffffed1004f00819 R12: 1ffff1100f718447
R13: ffff8880237d6320 R14: ffff88807b8c2240 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 00000000261a5000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 rcu_read_unlock include/linux/rcupdate.h:818 [inline]
 send_sigqueue+0x562/0x710 kernel/signal.c:2053
 posix_timer_event kernel/time/posix-timers.c:299 [inline]
 posix_timer_fn+0x14d/0x350 kernel/time/posix-timers.c:325
 __run_hrtimer kernel/time/hrtimer.c:1754 [inline]
 __hrtimer_run_queues+0x525/0xc10 kernel/time/hrtimer.c:1818
 hrtimer_interrupt+0x39d/0x980 kernel/time/hrtimer.c:1880
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
 __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:finish_task_switch+0x267/0x8f0 kernel/sched/core.c:5256
Code: 35 09 85 c0 0f 84 30 01 00 00 48 85 db 0f 85 4f 01 00 00 0f 1f 44 00 00 4c 89 e7 e8 e3 e9 3e 09 e8 2e 28 30 00 fb 4c 8b 65 b8 <49> 8d bc 24 00 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0
RSP: 0018:ffffc900048ef500 EFLAGS: 00000286
RAX: 3c1de00073c34200 RBX: 0000000000000000 RCX: 3c1de00073c34200
RDX: dffffc0000000000 RSI: ffffffff8acacfe0 RDI: ffffffff8b1d5160
RBP: ffffc900048ef550 R08: ffffffff91ff160f R09: 1ffffffff23fe2c1
R10: dffffc0000000000 R11: fffffbfff23fe2c2 R12: ffff88807b8c1e00
R13: 1ffff110171879a1 R14: dffffc0000000000 R15: ffff8880b8c3cd08
 context_switch kernel/sched/core.c:5385 [inline]
 __schedule+0x15b6/0x4660 kernel/sched/core.c:6701
 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6868
 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6892
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
 vprintk_emit+0x587/0x610 kernel/printk/printk.c:2342
 _printk+0xde/0x130 kernel/printk/printk.c:2366
 bt_err+0x122/0x180 net/bluetooth/lib.c:251
 hci_cmd_timeout+0xff/0x1e0 net/bluetooth/hci_core.c:1469
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>