rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: (detected by 1, t=10502 jiffies, g=13145, q=281 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 7247 (4294966707-4294959460), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 7249 jiffies! g13145 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:27520 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:
CPU: 1 UID: 0 PID: 52 Comm: kworker/u9:0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: hci6 hci_cmd_sync_work
RIP: 0010:finish_task_switch+0x242/0x940 kernel/sched/core.c:5114
Code: 0f 84 c2 01 00 00 48 85 db 0f 85 e9 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 68 13 ba 09 e8 33 3e 37 00 fb 4c 8b 65 c0 <49> 8d bc 24 48 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc90000bd6b78 EFLAGS: 00000286
RAX: b19b1f5564acbd00 RBX: 0000000000000000 RCX: b19b1f5564acbd00
RDX: 0000000000000007 RSI: ffffffff8d76bd39 RDI: ffffffff8bbfc660
RBP: ffffc90000bd6bd0 R08: ffffffff8f805a77 R09: 1ffffffff1f00b4e
R10: dffffc0000000000 R11: fffffbfff1f00b4f R12: ffff88801a7f1e80
R13: dffffc0000000000 R14: ffff88802a3ebd00 R15: ffff8880b893b358
FS: 0000000000000000(0000) GS:ffff8881261b1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c0036abd20 CR3: 000000007877e000 CR4: 00000000003526f0
Call Trace:
context_switch kernel/sched/core.c:5259 [inline]
__schedule+0x14c4/0x5000 kernel/sched/core.c:6863
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7190
irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x16c/0x340 kernel/locking/lockdep.c:5872
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 14 c5 d8 10 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90000bd6fb8 EFLAGS: 00000206
RAX: b19b1f5564acbd00 RBX: 0000000000000000 RCX: b19b1f5564acbd00
RDX: 000000008376bf33 RSI: ffffffff8d952009 RDI: ffffffff8bbfc660
RBP: ffffffff8173ef25 R08: ffffffff8173ef25 R09: ffffffff8df41cc0
R10: ffffc90000bd7188 R11: fffff5200017ae3d R12: 0000000000000002
R13: ffffffff8df41cc0 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
__unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:758
unwind_start arch/x86/include/asm/unwind.h:64 [inline]
arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf5/0x1f0 mm/page_owner.c:156
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:311
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1394 [inline]
__free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2901
__slab_free+0x21b/0x2a0 mm/slub.c:5999
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:352
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4948 [inline]
slab_alloc_node mm/slub.c:5258 [inline]
kmem_cache_alloc_node_noprof+0x433/0x710 mm/slub.c:5310
__alloc_skb+0x255/0x430 net/core/skbuff.c:679
alloc_skb include/linux/skbuff.h:1383 [inline]
mgmt_alloc_skb net/bluetooth/mgmt_util.c:64 [inline]
mgmt_send_event+0x46/0x190 net/bluetooth/mgmt_util.c:116
mgmt_connect_failed+0x39b/0x490 net/bluetooth/mgmt.c:-1
hci_conn_failed+0xda/0x310 net/bluetooth/hci_conn.c:1325
hci_abort_conn_sync+0x658/0xe30 net/bluetooth/hci_sync.c:5721
hci_cmd_sync_work+0x213/0x3a0 net/bluetooth/hci_sync.c:332
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