rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P48/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=44117, q=682906 ncpus=2)
task:kworker/u8:3 state:R running task stack:21888 pid:48 tgid:48 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: iou_exit io_ring_exit_work
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x15dd/0x52d0 kernel/sched/core.c:6908
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7235
irqentry_exit+0x599/0x620 kernel/entry/common.c:239
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x20b/0x2e0 kernel/locking/lockdep.c:5872
Code: e9 30 ff ff ff e8 d5 ed 0b 0a f7 c3 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 51 3b 7a 11 48 3b 44 24 30 75 33 fb 48 83 c4 38 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d ee 5a 73
RSP: 0018:ffffc90000b87198 EFLAGS: 00000282
RAX: 5cf62e599fa77e00 RBX: 0000000000000246 RCX: 0000000000000046
RDX: 00000000036493e5 RSI: ffffffff8e16369b RDI: ffffffff8c27ae80
RBP: 0000000000000000 R08: ffffffff81767a45 R09: ffffffff8e7602e0
R10: ffffc90000b872f8 R11: ffffffff81b0bb90 R12: 0000000000000002
R13: ffffffff8e7602e0 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
rcu_read_lock include/linux/rcupdate.h:850 [inline]
class_rcu_constructor include/linux/rcupdate.h:1193 [inline]
unwind_next_frame+0xc2/0x23c0 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4515 [inline]
slab_alloc_node mm/slub.c:4844 [inline]
kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4851
kmem_alloc_batch lib/debugobjects.c:371 [inline]
fill_pool+0x156/0x590 lib/debugobjects.c:420
debug_objects_fill_pool lib/debugobjects.c:742 [inline]
debug_object_activate+0x4a3/0x580 lib/debugobjects.c:831
debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline]
__call_rcu_common kernel/rcu/tree.c:3116 [inline]
call_rcu+0x43/0x890 kernel/rcu/tree.c:3251
slab_free_hook mm/slub.c:2656 [inline]
slab_free mm/slub.c:6143 [inline]
kmem_cache_free+0x439/0x630 mm/slub.c:6273
__io_req_caches_free+0x1c1/0x270 io_uring/io_uring.c:2133
io_req_caches_free+0x21/0x60 io_uring/io_uring.c:2145
io_ring_exit_work+0x41b/0x960 io_uring/io_uring.c:2339
process_one_work kernel/workqueue.c:3275 [inline]
process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
kthread+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51e/0xb90 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 3799 jiffies! g44117 f0x2 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:27648 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x15dd/0x52d0 kernel/sched/core.c:6908
__schedule_loop kernel/sched/core.c:6990 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7005
schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
kthread+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51e/0xb90 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 13 Comm: kworker/u8:1 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x17/0x70 kernel/kcov.c:217
Code: cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 65 48 8b 0d 18 2a 56 11 65 8b 15 39 2a 56 11 <81> e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 94 16 00 00
RSP: 0018:ffffc90000127718 EFLAGS: 00000202
RAX: ffffffff81b9b7dd RBX: 1ffff110170e812d RCX: ffff88801daadb80
RDX: 0000000000000001 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90000127860 R08: ffffffff90118cb7 R09: 1ffffffff2023196
R10: dffffc0000000000 R11: fffffbfff2023197 R12: ffff8880b8740968
R13: dffffc0000000000 R14: ffff8880b863bf80 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888125464000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000003e5030 CR3: 000000000e54c000 CR4: 00000000003526f0
Call Trace:
csd_lock_wait kernel/smp.c:342 [inline]
smp_call_function_many_cond+0xcfd/0x12c0 kernel/smp.c:877
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
on_each_cpu include/linux/smp.h:72 [inline]
smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2761 [inline]
smp_text_poke_batch_finish+0x5f5/0x1160 arch/x86/kernel/alternative.c:2971
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
static_key_enable_cpuslocked+0x128/0x240 kernel/jump_label.c:210
static_key_enable+0x1a/0x20 kernel/jump_label.c:223
toggle_allocation_gate+0xab/0x290 mm/kfence/core.c:900
process_one_work kernel/workqueue.c:3275 [inline]
process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
kthread+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245