rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 GPs behind) idle=9e7c/1/0x4000000000000000 softirq=28184/28185 fqs=1
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6101/1:b..l
rcu: (detected by 0, t=10506 jiffies, g=30973, q=560 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 7549 Comm: syz.3.430 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:num_possible_cpus include/linux/cpumask.h:1222 [inline]
RIP: 0010:mm_get_cid kernel/sched/sched.h:3849 [inline]
RIP: 0010:sched_mm_cid_fork+0x657/0x10e0 kernel/sched/core.c:10735
Code: c7 03 00 00 00 40 e9 19 01 00 00 49 c7 c4 b8 7e 3c 8e 49 c1 ec 03 41 bd 00 00 00 80 eb 0a 89 e8 f7 d8 0f 81 09 fe ff ff f3 90 <48> b8 00 00 00 00 00 fc ff df 41 0f b6 04 04 84 c0 75 40 44 8b 35
RSP: 0018:ffffc90004e7fc48 EFLAGS: 00000887
RAX: 0000000080000000 RBX: ffff88802a18a410 RCX: 0000000080000001
RDX: dffffc0000000000 RSI: 0000000000000002 RDI: ffff88802a18a410
RBP: 0000000080000000 R08: 1ffff11005431331 R09: 0000000000000000
R10: ffff88802a189acc R11: fffff520009cff78 R12: 1ffffffff1c78fd7
R13: 0000000080000000 R14: 0000000000000002 R15: ffff88802a189880
FS: 00007f59b07cc6c0(0000) GS:ffff888125306000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f333c9e9f00 CR3: 0000000077386000 CR4: 00000000003526f0
Call Trace:
bprm_execve+0xdc3/0x1450 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+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f59af99c819
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:00007f59b07cc028 EFLAGS: 00000246 ORIG_RAX: 0000000000000142
RAX: ffffffffffffffda RBX: 00007f59afc15fa0 RCX: 00007f59af99c819
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000007
RBP: 00007f59afa32c91 R08: 0000000000001000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f59afc16038 R14: 00007f59afc15fa0 R15: 00007fffc435ba58
task:udevd state:R running task stack:23832 pid:6101 tgid:6101 ppid:5213 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5354 [inline]
__schedule+0x165c/0x5520 kernel/sched/core.c:6966
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7294
irqentry_exit+0x5e4/0x700 kernel/entry/common.c:240
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872
Code: ff ff ff e8 f1 03 18 0a f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 ab 2f 9f 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 10 f0 1a 0a cc 48 8d 3d 18 96 94
RSP: 0018:ffffc900045c78d8 EFLAGS: 00000286
RAX: 2611f5a78196ef00 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 000000005a44979c RSI: ffffffff8e37de32 RDI: ffffffff8c2aa360
RBP: ffffffff81776256 R08: ffffffff81776256 R09: ffffffff8e95d060
R10: ffffc900045c7a38 R11: ffffffff81b1a400 R12: 0000000000000002
R13: ffffffff8e95d060 R14: 0000000000000000 R15: 0000000000000246
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+0xc3/0x2550 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
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:2689 [inline]
slab_free mm/slub.c:6242 [inline]
kmem_cache_free+0x182/0x650 mm/slub.c:6369
class_filename_destructor include/linux/fs.h:2547 [inline]
class_filename_flags_destructor include/linux/fs.h:2549 [inline]
do_readlinkat+0x451/0x510 fs/stat.c:594
__do_sys_readlink fs/stat.c:605 [inline]
__se_sys_readlink fs/stat.c:602 [inline]
__x64_sys_readlink+0x7f/0x90 fs/stat.c:602
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f07727153a7
RSP: 002b:00007ffca42cd758 EFLAGS: 00000206 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00007ffca42cdfa0 RCX: 00007f07727153a7
RDX: 0000000000000400 RSI: 00007ffca42cdb60 RDI: 00007ffca42cd760
RBP: 0000000000000200 R08: 000055929fbd4c29 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffca42cd760
R13: 00007ffca42cdb60 R14: 000055929fbd7ca4 R15: 000055929fbd7bcc
rcu: rcu_preempt kthread starved for 10500 jiffies! g30973 f0x0 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:27640 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5354 [inline]
__schedule+0x165c/0x5520 kernel/sched/core.c:6966
__schedule_loop kernel/sched/core.c:7049 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7064
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:436
ret_from_fork+0x514/0xb70 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: 0 UID: 0 PID: 49 Comm: kworker/u8:3 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x70 kernel/kcov.c:216
Code: 8b 3d e4 14 76 0c 48 89 de 5b e9 73 19 5e 00 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 c8 34 7b 11 65 8b 15 e9 34 7b 11 81 e2 00 01 ff 00 74
RSP: 0018:ffffc90000b976f8 EFLAGS: 00000202
RAX: ffffffff81ba6fe6 RBX: ffff8880b863c108 RCX: ffff88801b33bd00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90000b97840 R08: ffffffff9033b0f7 R09: 1ffffffff206761e
R10: dffffc0000000000 R11: fffffbfff206761f R12: 1ffff110170e8161
R13: dffffc0000000000 R14: ffff8880b8740b08 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888125206000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3ed0585980 CR3: 000000000e74a000 CR4: 00000000003526f0
Call Trace:
csd_lock_wait kernel/smp.c:342 [inline]
smp_call_function_many_cond+0xfe6/0x13d0 kernel/smp.c:892
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057
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:906
process_one_work kernel/workqueue.c:3278 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3361
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3442
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245