rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-....: (1 GPs behind) idle=a2dc/1/0x4000000000000000 softirq=48890/48891 fqs=270
rcu: hardirqs softirqs csw/system
rcu: number: 1062 0 0
rcu: cputime: 29 0 10570 ==> 10630(ms)
rcu: (t=10504 jiffies g=42837 q=715 ncpus=2)
rcu: rcu_preempt kthread starved for 1064 jiffies! g42837 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:27888 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:mISDN_clock_get+0x26/0x70 drivers/isdn/mISDN/clock.c:194
Code: 90 90 90 90 f3 0f 1e fa 55 53 e8 c5 16 74 f9 48 c7 c7 e0 11 cb 8f e8 f9 08 1a 03 48 89 c5 e8 91 42 61 f9 48 2b 05 3a e2 9a 12 <48> 89 ee 48 ba db 34 b6 d7 82 de 1b 43 48 89 c1 48 f7 ea 48 c7 c7
RSP: 0018:ffffc90000a08bc0 EFLAGS: 00000006
RAX: 0000008931e62e41 RBX: 0000000000000001 RCX: ffffffff81aa37c9
RDX: ffff88801d6e2480 RSI: ffffffff81aa37d7 RDI: 0000000000000004
RBP: 0000000000000046 R08: 0000000000000004 R09: 000000000001d038
R10: 000000000001d038 R11: 0000000000000001 R12: 1ffff9200014118f
R13: 0000000000000246 R14: ffffffff884cce70 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888124b0a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbc62aa3c97 CR3: 0000000060151000 CR4: 00000000003526f0
Call Trace:
dsp_cmx_send+0xeca/0x1790 drivers/isdn/mISDN/dsp_cmx.c:1639
call_timer_fn+0x19a/0x620 kernel/time/timer.c:1747
expire_timers kernel/time/timer.c:1798 [inline]
__run_timers+0x6ef/0x960 kernel/time/timer.c:2372
__run_timer_base kernel/time/timer.c:2384 [inline]
__run_timer_base kernel/time/timer.c:2376 [inline]
run_timer_base+0x114/0x190 kernel/time/timer.c:2393
run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2403
handle_softirqs+0x219/0x8e0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x109/0x170 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: 07 6d 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 43 d5 29 00 fb f4 3c 0a 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197de8 EFLAGS: 000002c6
RAX: 0000000001d7ad85 RBX: 0000000000000001 RCX: ffffffff8b6052a9
RDX: 0000000000000000 RSI: ffffffff8da2a299 RDI: ffffffff8bf06e40
RBP: ffffed1003adc490 R08: 0000000000000001 R09: ffffed10170a6655
R10: ffff8880b85332ab R11: 0000000000000001 R12: 0000000000000001
R13: ffff88801d6e2480 R14: ffffffff9081f6d0 R15: 0000000000000000
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:190 [inline]
do_idle+0x38d/0x500 kernel/sched/idle.c:330
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428
start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315
common_startup_64+0x13e/0x148
CPU: 0 UID: 0 PID: 1298 Comm: aoe_tx0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 16 e9 35 f6 48 89 df e8 fe 3c 36 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 45 46 26 f6 65 8b 05 7e 65 3e 08 85 c0 74 16 5b
RSP: 0018:ffffc9000430f958 EFLAGS: 00000246
RAX: 0000000000000006 RBX: ffffffff9add7240 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff8da2a299 RDI: ffffffff8bf06e40
RBP: 0000000000000293 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff9081f6d7 R11: 0000000000000001 R12: ffffffff8f05d120
R13: ffffffff9add7348 R14: 0000000000000000 R15: ffffffff9add7380
FS: 0000000000000000(0000) GS:ffff888124a0a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000032b83000 CR4: 00000000003526f0
Call Trace:
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
uart_port_unlock_irqrestore include/linux/serial_core.h:788 [inline]
uart_port_unlock_deref drivers/tty/serial/serial_core.c:91 [inline]
uart_port_unlock_deref drivers/tty/serial/serial_core.c:88 [inline]
uart_write_room+0x2d9/0x940 drivers/tty/serial/serial_core.c:647
tty_write_room+0x66/0x90 drivers/tty/tty_ioctl.c:69
handle_tx+0x14f/0x630 drivers/net/caif/caif_serial.c:212
__netdev_start_xmit include/linux/netdevice.h:5248 [inline]
netdev_start_xmit include/linux/netdevice.h:5257 [inline]
xmit_one net/core/dev.c:3845 [inline]
dev_hard_start_xmit+0x97/0x740 net/core/dev.c:3861
__dev_queue_xmit+0xa46/0x4490 net/core/dev.c:4763
dev_queue_xmit include/linux/netdevice.h:3365 [inline]
tx+0xcc/0x190 drivers/block/aoe/aoenet.c:62
kthread+0x1e4/0x3e0 drivers/block/aoe/aoecmd.c:1241
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245