rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (0 ticks this GP) idle=41dc/1/0x4000000000000000 softirq=77241/77241 fqs=2
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5192/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=60957, q=145 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 13692 Comm: syz.1.1559 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:_find_first_zero_bit+0x64/0xb0 lib/find_bit.c:149
Code: 06 48 83 f8 ff 74 2b 45 31 ed 48 f7 d0 f3 48 0f bc c0 4c 01 e8 48 39 d8 48 0f 43 c3 eb 05 31 db 48 89 d8 5b 41 5c 41 5d 41 5e <41> 5f c3 cc cc cc cc cc 49 83 c6 08 45 31 ed 4d 89 f7 eb 11 49 8b
RSP: 0018:ffffc900051bfc68 EFLAGS: 00000046
RAX: 0000000000000002 RBX: 0000000000000002 RCX: dffffc0000000000
RDX: dffffc0000000000 RSI: 0000000000000002 RDI: ffff8880785dc8d0
RBP: ffff8880785dc8d0 R08: 1ffff1100f0bb7c9 R09: 0000000000000000
R10: ffff8880785dbf8c R11: fffff52000a37f80 R12: 0000000080000000
R13: 1ffffffff1c355d3 R14: 0000000000000002 R15: ffff8880785dbd40
FS: 00007f94ceb806c0(0000) GS:ffff888125463000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f49f2140000 CR3: 000000007a356000 CR4: 00000000003526f0
Call Trace:
find_first_zero_bit include/linux/find.h:393 [inline]
__mm_get_cid kernel/sched/sched.h:3822 [inline]
mm_get_cid kernel/sched/sched.h:3837 [inline]
sched_mm_cid_fork+0x592/0xc80 kernel/sched/core.c:10704
bprm_execve+0xda1/0x1460 fs/exec.c:1771
do_execveat_common+0x50d/0x690 fs/exec.c:1846
__do_sys_execveat fs/exec.c:1941 [inline]
__se_sys_execveat fs/exec.c:1934 [inline]
__x64_sys_execveat+0xc7/0xf0 fs/exec.c:1934
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f94cdd9bf79
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:00007f94ceb80028 EFLAGS: 00000246 ORIG_RAX: 0000000000000142
RAX: ffffffffffffffda RBX: 00007f94ce015fa0 RCX: 00007f94cdd9bf79
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007f94cde327e0 R08: 0000000000001000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f94ce016038 R14: 00007f94ce015fa0 R15: 00007fff378ae398
task:udevd state:R running task stack:22944 pid:5192 tgid:5192 ppid:1 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x1585/0x5310 kernel/sched/core.c:6907
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7234
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:trace_lock_release include/trace/events/lock.h:69 [inline]
RIP: 0010:lock_release+0x4b/0x3d0 kernel/locking/lockdep.c:5879
Code: 89 44 24 28 0f 1f 44 00 00 65 8b 05 03 13 7a 11 83 f8 08 0f 83 56 02 00 00 89 c0 48 0f a3 05 6c c5 6f 0e 73 0d e8 85 f9 08 00 <84> c0 0f 84 94 02 00 00 83 3d b6 f7 6f 0e 00 0f 84 1c 02 00 00 65
RSP: 0018:ffffc90002fc7850 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffffff90b52101 RCX: 0000000080000001
RDX: ffffc90002fc7901 RSI: ffffffff8c27a460 RDI: ffffffff8c27a420
RBP: dffffc0000000000 R08: ffffc90002fc7e10 R09: 0000000000000000
R10: ffffc90002fc79d8 R11: fffff520005f8f3d R12: ffffc90002fc7e20
R13: ffffffff81768a45 R14: ffffffff8e7602e0 R15: ffffffff81768a45
rcu_lock_release include/linux/rcupdate.h:322 [inline]
rcu_read_unlock include/linux/rcupdate.h:881 [inline]
class_rcu_destructor include/linux/rcupdate.h:1193 [inline]
unwind_next_frame+0x1aaa/0x23c0 arch/x86/kernel/unwind_orc.c:695
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
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2687 [inline]
slab_free mm/slub.c:6124 [inline]
kmem_cache_free+0x187/0x630 mm/slub.c:6254
file_free fs/file_table.c:71 [inline]
__fput+0x6c5/0xa70 fs/file_table.c:482
fput_close_sync+0x11f/0x240 fs/file_table.c:574
__do_sys_close fs/open.c:1509 [inline]
__se_sys_close fs/open.c:1494 [inline]
__x64_sys_close+0x7e/0x110 fs/open.c:1494
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f49f1b15a67
RSP: 002b:00007ffec2a471e8 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000559d301f54a0 RCX: 00007f49f1b15a67
RDX: 000000000000e141 RSI: 00007f49f1bf1b20 RDI: 000000000000000d
RBP: 0000559d301b7cb0 R08: 0000000000006100 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000202 R12: 0000559d301ad7b0
R13: 00000000000000ff R14: 0000559d12928be0 R15: 00007ffec2a47460
rcu: rcu_preempt kthread starved for 10498 jiffies! g60957 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:27616 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x1585/0x5310 kernel/sched/core.c:6907
__schedule_loop kernel/sched/core.c:6989 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7004
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:
CPU: 1 UID: 0 PID: 573 Comm: kworker/u8:6 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xcea/0x12c0 kernel/smp.c:877
Code: 89 ee 83 e6 01 31 ff e8 24 e3 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 cf de 0b 00 eb 38 f3 90 42 0f b6 04 2b <84> c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 b3 de 0b 00 eb e4 44
RSP: 0018:ffffc900036e7760 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 1ffff110170c8515 RCX: ffff888025ca0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900036e78a0 R08: ffffffff901182b7 R09: 1ffffffff2023056
R10: dffffc0000000000 R11: fffffbfff2023057 R12: ffff8880b86428a8
R13: dffffc0000000000 R14: ffff8880b873bf80 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125563000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000002c5030 CR3: 000000000e54c000 CR4: 00000000003526f0
Call Trace:
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:2746 [inline]
smp_text_poke_batch_finish+0x5f5/0x1160 arch/x86/kernel/alternative.c:2956
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
static_key_disable_cpuslocked+0xc5/0x1a0 kernel/jump_label.c:240
static_key_disable+0x1a/0x20 kernel/jump_label.c:248
toggle_allocation_gate+0x1fe/0x290 mm/kfence/core.c:906
process_one_work+0x949/0x1650 kernel/workqueue.c:3279
process_scheduled_works kernel/workqueue.c:3362 [inline]
worker_thread+0xb46/0x1140 kernel/workqueue.c:3443
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