rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (3 ticks this GP) idle=d534/1/0x4000000000000000 softirq=67415/67426 fqs=1325
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6126/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=70589, q=450 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 12104 Comm: syz.4.1412 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:__sanitizer_cov_trace_pc+0x3f/0x70 kernel/kcov.c:217
Code: 02 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 e9 11 b9 85 09 8b 82 d4 16 00 00 85 c0 74 f1 8b 82 b0 16 00 00 <83> f8 02 75 e6 48 8b 8a b8 16 00 00 8b 92 b4 16 00 00 48 8b 01 48
RSP: 0000:ffffc90006f4fcd0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff888021ac3f00 RCX: ffffffff8540dcb6
RDX: ffff888079db4a00 RSI: ffffffff8540dcc3 RDI: ffff888079db4a00
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff888021ac3f20 R14: ffff888021ac3f24 R15: 0000000000000000
FS: 0000555558229500(0000) GS:ffff88812436a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f30699f6d58 CR3: 000000009d4b3000 CR4: 00000000003526f0
Call Trace:
__vga_put+0x653/0x790 drivers/pci/vgaarb.c:394
vga_put+0xa8/0x100 drivers/pci/vgaarb.c:560
vga_arb_release+0x25e/0x540 drivers/pci/vgaarb.c:1439
__fput+0x3ff/0xb50 fs/file_table.c:510
task_work_run+0x150/0x240 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
exit_to_user_mode_loop+0x107/0x4f0 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x706/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f959979ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff02d74258 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fff02d74340 RCX: 00007f959979ce59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000009f085 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b32820000 R11: 0000000000000246 R12: 00007fff02d74380
R13: 00007f9599a15fac R14: 000000000009f11f R15: 00007f9599a15fa0
task:kworker/u8:12 state:R running task stack:25096 pid:6126 tgid:6126 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1295/0x67a0 kernel/sched/core.c:7189
preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7513
irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline]
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x205/0x7e0 kernel/entry/common.c:164
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872
Code: 05 3b d2 26 12 83 f8 07 0f 87 d9 02 00 00 48 0f a3 05 46 5a f3 0e 0f 82 a4 02 00 00 8b 35 ce 8d f3 0e 85 f6 0f 85 bf 00 00 00 <48> 8b 44 24 30 65 48 2b 05 dd d1 26 12 0f 85 ed 02 00 00 48 83 c4
RSP: 0018:ffffc900075c7a20 EFLAGS: 00000206
RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000003
RDX: 0000000000000000 RSI: ffffffff8defee33 RDI: ffffffff8c1c4380
RBP: ffffffff8e7e5620 R08: 0000000039928aa1 R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
rcu_read_lock include/linux/rcupdate.h:838 [inline]
batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:767 [inline]
batadv_iv_ogm_schedule_buff+0x5a4/0x1650 net/batman-adv/bat_iv_ogm.c:848
batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:904 [inline]
batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:897 [inline]
batadv_iv_send_outstanding_bat_ogm_packet+0x6dd/0x860 net/batman-adv/bat_iv_ogm.c:1793
process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314
process_scheduled_works kernel/workqueue.c:3397 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: rcu_preempt kthread starved for 7835 jiffies! g70589 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:27992 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1295/0x67a0 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7283
schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 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:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: 56 92 02 e9 c3 42 03 00 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 63 51 20 00 fb f4 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197df0 EFLAGS: 00000242
RAX: 0000000002caffbf RBX: ffff88801e2ba500 RCX: ffffffff8b8b4095
RDX: 0000000000000000 RSI: ffffffff8df24341 RDI: ffffffff8c1c4380
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed10170a67b5
R10: ffff8880b8533dab R11: 0000000000000000 R12: 0000000000000001
R13: ffffed1003c574a0 R14: 0000000000000001 R15: ffffffff90d7e850
FS: 0000000000000000(0000) GS:ffff88812446a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1e53b541d0 CR3: 0000000076b40000 CR4: 00000000003526f0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline]
default_idle+0x9/0x10 arch/x86/kernel/process.c:767
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x464/0x590 kernel/sched/idle.c:352
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:451
start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x148