rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=447c/1/0x4000000000000000 softirq=112332/112333 fqs=0
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P18725/1:b..l P18716/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=122341, q=5136 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 18731 Comm: syz.7.3445 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:arch_atomic_try_cmpxchg arch/x86/include/asm/atomic.h:107 [inline]
RIP: 0010:raw_atomic_try_cmpxchg_acquire include/linux/atomic/atomic-arch-fallback.h:2170 [inline]
RIP: 0010:atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1302 [inline]
RIP: 0010:queued_spin_lock include/asm-generic/qspinlock.h:111 [inline]
RIP: 0010:do_raw_spin_lock+0x139/0x260 kernel/locking/spinlock_debug.c:116
Code: 28 00 00 00 00 e8 17 bc 91 00 be 04 00 00 00 48 8d 7c 24 28 e8 08 bc 91 00 8b 44 24 28 ba 01 00 00 00 89 44 24 04 f0 0f b1 13 <0f> 85 93 00 00 00 48 89 ea 65 44 8b 35 9a b1 24 12 48 b8 00 00 00
RSP: 0018:ffffc90000007df0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff8880b84284c0 RCX: ffffffff81e4de78
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000007e18
RBP: ffff8880b84284c8 R08: 0000000000000001 R09: fffff52000000fc3
R10: 0000000000000003 R11: 0000000000000001 R12: 1ffff92000000fbf
R13: ffff8880b84284d0 R14: dffffc0000000000 R15: ffff8880b8428750
FS: 00007f417d5766c0(0000) GS:ffff888124387000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b34602ff8 CR3: 000000005ded9000 CR4: 00000000003526f0
Call Trace:
__run_hrtimer kernel/time/hrtimer.c:1934 [inline]
__hrtimer_run_queues+0x1bd/0xa00 kernel/time/hrtimer.c:1994
hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:finish_task_switch.isra.0+0x2d3/0x1010 kernel/sched/core.c:5245
Code: 2f 0a 00 00 41 c7 87 e0 0d 00 00 00 00 00 00 e9 0f 04 00 00 49 8d 7f 48 e8 ea 2a b7 09 e8 c5 9e 3b 00 fb 48 8d bb c8 16 00 00 <48> b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 04 02 84
RSP: 0018:ffffc90002fff4c8 EFLAGS: 00000206
RAX: 000000000000d0e1 RBX: ffff888059a40000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8df0fdfe RDI: ffff888059a416c8
RBP: ffffc90002fff520 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: ffffffff81d55522 R12: ffff888032c9ca80
R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8880b843b480
context_switch kernel/sched/core.c:5391 [inline]
__schedule+0x129d/0x67a0 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7283
schedule_timeout+0x1b2/0x280 kernel/time/sleep_timeout.c:75
unix_wait_for_peer+0x268/0x2a0 net/unix/af_unix.c:1622
unix_dgram_sendmsg+0x1696/0x1810 net/unix/af_unix.c:2261
sock_sendmsg_nosec net/socket.c:787 [inline]
__sock_sendmsg net/socket.c:802 [inline]
____sys_sendmsg+0x9e1/0xb70 net/socket.c:2699
___sys_sendmsg+0x190/0x1e0 net/socket.c:2753
__sys_sendmmsg+0x205/0x430 net/socket.c:2842
__do_sys_sendmmsg net/socket.c:2869 [inline]
__se_sys_sendmmsg net/socket.c:2866 [inline]
__x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2866
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f417c79ce59
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:00007f417d576028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f417ca15fa0 RCX: 00007f417c79ce59
RDX: 0000000000000651 RSI: 0000200000000000 RDI: 0000000000000004
RBP: 00007f417c832d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f417ca16038 R14: 00007f417ca15fa0 R15: 00007fff5d3415f8
task:syz.5.3439 state:R running task stack:23816 pid:18716 tgid:18714 ppid:7838 task_flags:0x400640 flags:0x00080000
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+0x205/0x970 kernel/entry/common.c:164
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_is_held_type+0xf5/0x140 kernel/locking/lockdep.c:5945
Code: ff ff ff ff 65 0f c1 15 f1 45 80 08 83 fa 01 8b 44 24 04 75 2d 9c 5a 80 e6 02 75 47 41 f7 c5 00 02 00 00 74 01 fb 48 83 c4 08 <5b> 5d 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc e9 d7 3a 03 00 31 c0
RSP: 0018:ffffc900031defe8 EFLAGS: 00000286
RAX: 0000000000000000 RBX: ffffffff8e849b20 RCX: 0000000000000001
RDX: 0000000000000046 RSI: ffffffff8deea8b5 RDI: ffffffff8c1c4780
RBP: ffff888032c9ca80 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00000000ffffffff
R13: 0000000000000246 R14: ffff888032c9d660 R15: 0000000000000002
lock_is_held include/linux/lockdep.h:249 [inline]
task_css include/linux/cgroup.h:522 [inline]
task_freezer kernel/cgroup/legacy_freezer.c:51 [inline]
cgroup1_freezing+0x174/0x3b0 kernel/cgroup/legacy_freezer.c:64
freezing_slow_path+0xfc/0x1a0 kernel/freezer.c:47
freezing include/linux/freezer.h:41 [inline]
dump_interrupted+0x76/0xe0 fs/coredump.c:587
dump_emit_page fs/coredump.c:1299 [inline]
dump_user_range+0x352/0xad0 fs/coredump.c:1378
elf_core_dump+0x2d5f/0x3d10 fs/binfmt_elf.c:2109
coredump_write fs/coredump.c:1053 [inline]
do_coredump fs/coredump.c:1132 [inline]
vfs_coredump+0x2980/0x5770 fs/coredump.c:1206
get_signal+0x2162/0x2210 kernel/signal.c:3023
arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop+0x98/0x670 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+0x666/0x870 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff34819ce59
RSP: 002b:00007ff3490f70e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007ff348416098 RCX: 00007ff34819ce59
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007ff34841609c
RBP: 00007ff348416090 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff348416128 R14: 00007ffd6a7df800 R15: 00007ffd6a7df8e8
task:syz.0.3442 state:R running task stack:23640 pid:18725 tgid:18724 ppid:16654 task_flags:0x400140 flags:0x00080004
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+0x205/0x970 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 fb 03 25 12 83 f8 07 0f 87 d9 02 00 00 48 0f a3 05 06 8d f2 0e 0f 82 a4 02 00 00 8b 35 8e c0 f2 0e 85 f6 0f 85 bf 00 00 00 <48> 8b 44 24 30 65 48 2b 05 9d 03 25 12 0f 85 ed 02 00 00 48 83 c4
RSP: 0018:ffffc90005ed76f0 EFLAGS: 00000206
RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8deea8b5 RDI: ffffffff8c1c4780
RBP: ffffffff8e7e5560 R08: 000000002de9239f 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]
class_rcu_constructor include/linux/rcupdate.h:1181 [inline]
unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556
__call_rcu_common.constprop.0+0xa5/0x9b0 kernel/rcu/tree.c:3131
slab_free_hook mm/slub.c:2653 [inline]
slab_free mm/slub.c:6251 [inline]
kmem_cache_free+0x44a/0x6c0 mm/slub.c:6378
__io_req_caches_free+0x1a6/0x220 io_uring/io_uring.c:2152
io_queue_deferred+0x9c/0x2fe io_uring/io_uring.c:461
io_drain_req io_uring/io_uring.c:1360 [inline]
io_queue_sqe_fallback.cold+0x333/0x3cc io_uring/io_uring.c:1678
io_submit_sqe io_uring/io_uring.c:1933 [inline]
io_submit_sqes+0x15a8/0x24b0 io_uring/io_uring.c:2061
__do_sys_io_uring_enter+0xa88/0x1b50 io_uring/io_uring.c:2651
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4f9419ce59
RSP: 002b:00007f4f923f5f38 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 0000200000001540 RCX: 00007f4f9419ce59
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000006
RBP: 00000000000001f0 R08: 0000000000000000 R09: 0000000000000008
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000d40
R13: 0000200000000d48 R14: 0000000000000f14 R15: 0000000000000000
rcu: rcu_preempt kthread starved for 10502 jiffies! g122341 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:27848 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: 18000 Comm: kworker/u8:5 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0x58e/0x1700 kernel/smp.c:892
Code: 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 a9 83 0c 00 f3 90 41 0f b6 45 00 <41> 38 c4 7c 08 84 c0 0f 85 63 0f 00 00 8b 45 08 31 ff 83 e0 01 41
RSP: 0000:ffffc90004c5f870 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81fc2dfd
RDX: ffff88807ce18000 RSI: ffffffff81fc2dd7 RDI: ffff88807ce18000
RBP: ffff8880b8443560 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003
R13: ffffed10170886ad R14: 0000000000000001 R15: ffff8880b853c800
FS: 0000000000000000(0000) GS:ffff888124487000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f417a9f5ff8 CR3: 000000000e596000 CR4: 00000000003526f0
Call Trace:
on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057
on_each_cpu include/linux/smp.h:72 [inline]
smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline]
smp_text_poke_batch_finish+0x337/0xc60 arch/x86/kernel/alternative.c:2983
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
jump_label_update+0x37a/0x550 kernel/jump_label.c:910
static_key_enable_cpuslocked+0x1bc/0x270 kernel/jump_label.c:210
static_key_enable+0x1a/0x20 kernel/jump_label.c:223
toggle_allocation_gate mm/kfence/core.c:906 [inline]
toggle_allocation_gate+0xfe/0x2d0 mm/kfence/core.c:898
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