rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P2936/1:b..l P6719/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=18201, q=363 ncpus=2)
task:syz.1.177 state:R running task stack:26856 pid:6719 ppid:5770 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867
preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
unwind_next_frame+0x200f/0x2970 arch/x86/kernel/unwind_orc.c:672
arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
save_stack+0x125/0x230 mm/page_owner.c:128
__reset_page_owner+0x4e/0x190 mm/page_owner.c:149
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1181 [inline]
free_unref_page_prepare+0x7b2/0x8c0 mm/page_alloc.c:2365
free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2504
release_pages+0x1f7a/0x2200 mm/swap.c:1022
tlb_batch_pages_flush mm/mmu_gather.c:99 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:294 [inline]
tlb_flush_mmu+0x379/0x510 mm/mmu_gather.c:301
tlb_finish_mmu+0xf9/0x220 mm/mmu_gather.c:425
exit_mmap+0x428/0xb90 mm/mmap.c:3315
__mmput+0x118/0x3c0 kernel/fork.c:1355
exit_mm+0x1f2/0x2c0 kernel/exit.c:569
do_exit+0x8dd/0x2460 kernel/exit.c:870
do_group_exit+0x21b/0x2d0 kernel/exit.c:1024
get_signal+0x12fc/0x13f0 kernel/signal.c:2902
arch_do_signal_or_restart+0xc2/0x800 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f26f419c799
RSP: 002b:00007f26f50e5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000120
RAX: fffffffffffffe00 RBX: 00007f26f4415fa0 RCX: 00007f26f419c799
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f26f4232c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000800 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f26f4416038 R14: 00007f26f4415fa0 R15: 00007ffc09455b28
task:kworker/u4:7 state:R running task stack:24080 pid:2936 ppid:2 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010
irqentry_exit+0x67/0x70 kernel/entry/common.c:438
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:lock_acquire+0x208/0x420 kernel/locking/lockdep.c:5758
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc9000c3f7a40 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 6a65dda45b4c9000
RDX: 0000000000000000 RSI: ffffffff8acadb60 RDI: ffffffff8b1c89a0
RBP: ffffc9000c3f7b48 R08: dffffc0000000000 R09: 1ffffffff22386a0
R10: dffffc0000000000 R11: fffffbfff22386a1 R12: 1ffff9200187ef54
R13: ffffffff8d1320a0 R14: 0000000000000246 R15: dffffc0000000000
rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
rcu_read_lock include/linux/rcupdate.h:786 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
batadv_nc_worker+0xef/0x610 net/batman-adv/network-coding.c:719
process_one_work kernel/workqueue.c:2653 [inline]
process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811
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
rcu: rcu_preempt kthread starved for 10443 jiffies! g18201 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:27720 pid:17 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x313/0x1590 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
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: 0 Comm: swapper/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148
Code: 6f 21 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d 23 39 42 00 fb f4 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2e 41 89 de 80
RSP: 0018:ffffffff8ce07d80 EFLAGS: 000002c6
RAX: 1ac720b7e9e1fc00 RBX: ffffffff8162a8c1 RCX: 1ac720b7e9e1fc00
RDX: 0000000000000001 RSI: ffffffff8acac9e0 RDI: ffffffff8b1c89a0
RBP: ffffffff8ce07eb8 R08: ffff8880b8e36b2b R09: 1ffff110171c6d65
R10: dffffc0000000000 R11: ffffed10171c6d66 R12: 1ffffffff19c0fbc
R13: dffffc0000000000 R14: 1ffffffff19d2688 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f51248d1eb2 CR3: 0000000030d8f000 CR4: 00000000003506f0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:753
default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
cpuidle_idle_call kernel/sched/idle.c:178 [inline]
do_idle+0x221/0x590 kernel/sched/idle.c:302
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:401
rest_init+0x2e2/0x300 init/main.c:744
arch_call_rest_init+0xe/0x10 init/main.c:841
start_kernel+0x459/0x4e0 init/main.c:1086
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555
x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536
secondary_startup_64_no_verify+0x179/0x17b
sched: RT throttling activated