rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: (detected by 0, t=10502 jiffies, g=50725, q=263 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295000987-4294990485), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10502 jiffies! g50725 f0x2 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:26880 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
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: 6883 Comm: kworker/u8:22 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
RIP: 0010:rcu_lock_release include/linux/rcupdate.h:341 [inline]
RIP: 0010:rcu_read_unlock include/linux/rcupdate.h:897 [inline]
RIP: 0010:advance_sched+0xb14/0xc90 net/sched/sch_taprio.c:993
Code: 22 88 4f f8 eb 24 e8 1b 88 4f f8 c6 05 e8 fc f9 05 01 48 c7 c7 40 26 74 8c be 80 03 00 00 48 c7 c2 e0 26 74 8c e8 0c 99 2c f8 <48> c7 c7 e0 19 f4 8d 48 89 de e8 8d 7c 2c f8 e8 a8 2a 36 f8 b8 01
RSP: 0018:ffffc90000a08c70 EFLAGS: 00000006
RAX: ffffffff897228ac RBX: ffffffff897227e8 RCX: ffff888027000000
RDX: 0000000000010000 RSI: ffffffff8bc08340 RDI: ffffffff8bc08300
RBP: 0000000000000001 R08: ffff888026dd019f R09: 1ffff11004dba033
R10: dffffc0000000000 R11: ffffed1004dba034 R12: ffff888026dd0320
R13: ffff888026dd0000 R14: 1888dd63d0000000 R15: ffff88807f19ec00
FS: 0000000000000000(0000) GS:ffff888125f35000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f81e23156c0 CR3: 0000000050dfd000 CR4: 0000000000350ef0
Call Trace:
__run_hrtimer kernel/time/hrtimer.c:1777 [inline]
__hrtimer_run_queues+0x51c/0xc30 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
__sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:rcu_preempt_read_exit kernel/rcu/tree_plugin.h:396 [inline]
RIP: 0010:__rcu_read_unlock+0x2e/0xe0 kernel/rcu/tree_plugin.h:435
Code: 41 57 41 56 41 55 41 54 53 49 bf 00 00 00 00 00 fc ff df 65 48 8b 3c 25 08 b0 7e 92 48 8d 9f 84 04 00 00 49 89 dc 49 c1 ec 03 <43> 0f b6 04 3c 84 c0 75 4f ff 0b 75 1d 4c 8d b7 88 04 00 00 4c 89
RSP: 0018:ffffc9000ca57168 EFLAGS: 00000217
RAX: 42871a7f95966700 RBX: ffff888027000484 RCX: 42871a7f95966700
RDX: 0000000000000004 RSI: ffffffff8d978ed0 RDI: ffff888027000000
RBP: dffffc0000000000 R08: ffffc9000ca573a0 R09: ffffc9000ca572b8
R10: dffffc0000000000 R11: fffff5200194ae59 R12: 1ffff11004e00090
R13: ffffc9000ca50000 R14: ffffc9000ca57268 R15: dffffc0000000000
rcu_read_unlock include/linux/rcupdate.h:899 [inline]
class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0x19ae/0x2390 arch/x86/kernel/unwind_orc.c:680
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
unpoison_slab_object mm/kasan/common.c:339 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:365
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4953 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5270
__build_skb net/core/skbuff.c:474 [inline]
__netdev_alloc_skb+0x226/0x960 net/core/skbuff.c:784
__netdev_alloc_skb_ip_align include/linux/skbuff.h:3504 [inline]
netdev_alloc_skb_ip_align include/linux/skbuff.h:3514 [inline]
batadv_iv_ogm_aggregate_new net/batman-adv/bat_iv_ogm.c:566 [inline]
batadv_iv_ogm_queue_add+0x825/0xd30 net/batman-adv/bat_iv_ogm.c:677
batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:854 [inline]
batadv_iv_ogm_schedule+0xb48/0xf00 net/batman-adv/bat_iv_ogm.c:873
batadv_iv_send_outstanding_bat_ogm_packet+0x6c6/0x7e0 net/batman-adv/bat_iv_ogm.c:1709
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246