rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=d904/1/0x4000000000000000 softirq=98309/98316 fqs=4
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P15362/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=92541, q=746 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 15335 Comm: syz.2.2921 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:_find_first_zero_bit+0x12/0xb0 lib/find_bit.c:-1
Code: ff 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 55 41 54 53 48 85 f6 74 46 <48> 89 f3 49 89 fe 49 bc 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8
RSP: 0018:ffffc90003ab7c18 EFLAGS: 00000002
RAX: 0000000000000000 RBX: ffff888030d70b90 RCX: 0000000080000001
RDX: dffffc0000000000 RSI: 0000000000000002 RDI: ffff888030d70b90
RBP: 0000000080000000 R08: 1ffff110061ae021 R09: 0000000000000000
R10: ffff888030d70254 R11: fffff52000756f78 R12: 1ffffffff1c361d3
R13: 0000000080000000 R14: 0000000000000002 R15: ffff888030d70000
FS: 00007f695d8686c0(0000) GS:ffff88812545d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f98c2683d58 CR3: 0000000048bf2000 CR4: 00000000003526f0
Call Trace:
find_first_zero_bit include/linux/find.h:393 [inline]
__mm_get_cid kernel/sched/sched.h:3835 [inline]
mm_get_cid kernel/sched/sched.h:3850 [inline]
sched_mm_cid_fork+0x5d5/0x1120 kernel/sched/core.c:10679
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: 0033:0x7f695c99c799
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:00007f695d868028 EFLAGS: 00000246 ORIG_RAX: 0000000000000142
RAX: ffffffffffffffda RBX: 00007f695cc15fa0 RCX: 00007f695c99c799
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007f695ca32c99 R08: 0000000000001000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f695cc16038 R14: 00007f695cc15fa0 R15: 00007f695cd3fa48
task:syz-executor state:R running task stack:28128 pid:15362 tgid:15362 ppid:12601 task_flags:0x400040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7238
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:check_kcov_mode kernel/kcov.c:194 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:246 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x36/0x90 kernel/kcov.c:314
Code: b8 8a 56 11 65 8b 0d d9 8a 56 11 81 e1 00 01 ff 00 74 11 81 f9 00 01 00 00 75 5b 83 ba a4 16 00 00 00 74 52 8b 8a 80 16 00 00 <83> f9 03 75 47 48 8b 8a 88 16 00 00 44 8b 8a 84 16 00 00 49 c1 e1
RSP: 0018:ffffc90003a97868 EFLAGS: 00000246
RAX: ffffffff826b9c66 RBX: ffff88802e869800 RCX: 0000000000000000
RDX: ffff88803275bd00 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 00000000000081a4 R08: ffffffff826b9b96 R09: ffffffff8e75e520
R10: dffffc0000000000 R11: ffffed10064eb8e8 R12: ffff888057e40ae4
R13: 0000000000000001 R14: dffffc0000000000 R15: ffff88803275bd00
task_dump_owner+0x146/0x4c0 fs/proc/base.c:1893
pid_update_inode fs/proc/base.c:2053 [inline]
proc_pident_instantiate+0x1e6/0x2b0 fs/proc/base.c:2709
proc_pident_lookup+0x1b7/0x270 fs/proc/base.c:2732
lookup_open fs/namei.c:4456 [inline]
open_last_lookups fs/namei.c:4583 [inline]
path_openat+0x11ac/0x3860 fs/namei.c:4827
do_file_open+0x23e/0x4a0 fs/namei.c:4859
do_sys_openat2+0x113/0x200 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1383
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: 0033:0x7f4c3515cfce
RSP: 002b:00007f4c3553f7f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 000055555ffd0500 RCX: 00007f4c3515cfce
RDX: 0000000000080001 RSI: 00007f4c35233c2e RDI: ffffffffffffff9c
RBP: 00007f4c35233c2e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 00007f4c3553f8d0 R14: 00000000000a47d4 R15: 00007f4c3553fe40
rcu: rcu_preempt kthread starved for 10494 jiffies! g92541 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:27656 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7008
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+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: 10045 Comm: kworker/u8:9 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xce5/0x12c0 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 b4 e6 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 5f e2 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 43 e2
RSP: 0018:ffffc900043af700 EFLAGS: 00000293
RAX: ffffffff81b9bebd RBX: 1ffff110170c8515 RCX: ffff8880307e9e80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900043af840 R08: ffffffff9011a7b7 R09: 1ffffffff20234f6
R10: dffffc0000000000 R11: fffffbfff20234f7 R12: ffff8880b86428a8
R13: dffffc0000000000 R14: ffff8880b873bf80 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88812555d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f98c1785900 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: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:3276 [inline]
process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245