rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (0 ticks this GP) idle=156c/1/0x4000000000000000 softirq=54104/54104 fqs=2
rcu: (detected by 0, t=10502 jiffies, g=33749, q=260 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 10754 Comm: syz.4.1148 Not tainted 6.15.0-syzkaller-13659-g5b032cac6225 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:hlock_id kernel/locking/lockdep.c:436 [inline]
RIP: 0010:__lock_acquire+0x631/0x1c90 kernel/locking/lockdep.c:5228
Code: 0f 0f 45 85 d2 75 23 85 db 0f 85 66 04 00 00 4c 89 ef 89 4c 24 08 e8 9e ac ff ff 8b 4c 24 08 48 83 78 40 00 0f 84 a1 0a 00 00 <0f> b7 44 24 10 8b 74 24 18 44 8b 74 24 28 c1 e0 0d 66 0b 04 24 98
RSP: 0018:ffffc90000a08cf0 EFLAGS: 00000082
RAX: ffffffff95d3fe88 RBX: 0000000000000001 RCX: 00000000fffffffe
RDX: 0000000000000000 RSI: ffff88807c442f58 RDI: ffff88807c442f58
RBP: ffff88807c442440 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88807c442f30
R13: ffff88807c442f58 R14: 0000000000000001 R15: 0000000000000002
FS: 0000000000000000(0000) GS:ffff888124854000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000005c4d1000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire kernel/locking/lockdep.c:5871 [inline]
lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
_raw_spin_lock_irq+0x36/0x50 kernel/locking/spinlock.c:170
__run_hrtimer kernel/time/hrtimer.c:1765 [inline]
__hrtimer_run_queues+0x2bc/0xad0 kernel/time/hrtimer.c:1825
hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
__sysvec_apic_timer_interrupt+0x108/0x3f0 arch/x86/kernel/apic/apic.c:1056
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline]
RIP: 0010:lock_acquire+0x4e/0x350 kernel/locking/lockdep.c:5834
Code: 48 8b 05 1d 42 34 12 48 89 44 24 30 31 c0 66 90 65 8b 05 39 42 34 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 42 9d 0f 0f <0f> 82 74 02 00 00 8b 35 2a cf 0f 0f 85 f6 0f 85 8d 00 00 00 48 8b
RSP: 0018:ffffc9001c747710 EFLAGS: 00000297
RAX: 0000000000000001 RBX: ffffffff8e5c4cc0 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e5c4cc0
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 000000000001229f R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:841 [inline]
class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
unwind_next_frame+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
kmalloc_noprof include/linux/slab.h:905 [inline]
slab_free_hook mm/slub.c:2333 [inline]
slab_free mm/slub.c:4643 [inline]
kmem_cache_free+0x142/0x4d0 mm/slub.c:4745
exit_mmap+0x511/0xb90 mm/mmap.c:1309
__mmput+0x12a/0x410 kernel/fork.c:1121
mmput+0x62/0x70 kernel/fork.c:1144
exit_mm kernel/exit.c:581 [inline]
do_exit+0x7bc/0x2bd0 kernel/exit.c:943
do_group_exit+0xd3/0x2a0 kernel/exit.c:1104
__do_sys_exit_group kernel/exit.c:1115 [inline]
__se_sys_exit_group kernel/exit.c:1113 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1113
x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9cb7f8e929
Code: Unable to access opcode bytes at 0x7f9cb7f8e8ff.
RSP: 002b:00007ffd91593918 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9cb7f8e929
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffd9159397c R08: 0000000291593a0f R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 00000000000000e0
R13: 00000000000927c0 R14: 000000000006845c R15: 00007ffd915939d0
rcu: rcu_preempt kthread starved for 10490 jiffies! g33749 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:27928 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5396 [inline]
__schedule+0x116a/0x5de0 kernel/sched/core.c:6785
__schedule_loop kernel/sched/core.c:6863 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6878
schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054
rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256
kthread+0x3c5/0x780 kernel/kthread.c:464
ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
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: 3500 Comm: kworker/u8:6 Not tainted 6.15.0-syzkaller-13659-g5b032cac6225 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:write_comp_data+0x11/0x90 kernel/kcov.c:246
Code: cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 49 89 d2 49 89 f8 49 89 f1 65 48 8b 15 07 b0 10 12 <65> 8b 05 18 b0 10 12 a9 00 01 ff 00 74 1d f6 c4 01 74 67 a9 00 00
RSP: 0018:ffffc9000c237898 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffff8880b85417e0 RCX: ffffffff81affaed
RDX: ffff8880332b8000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000
R13: 0000000000000003 R14: ffffed10170a82fd R15: ffff8880b843cf40
FS: 0000000000000000(0000) GS:ffff888124754000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5957db3f98 CR3: 000000000e382000 CR4: 00000000003526f0
DR0: 0000000000000007 DR1: 0000000000004e6a DR2: 0000000000000007
DR3: 00000000000002d5 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
csd_lock_wait kernel/smp.c:340 [inline]
smp_call_function_many_cond+0xd9d/0x1510 kernel/smp.c:885
on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052
on_each_cpu include/linux/smp.h:71 [inline]
smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2660 [inline]
smp_text_poke_batch_finish+0x27b/0xdb0 arch/x86/kernel/alternative.c:2870
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
jump_label_update+0x376/0x550 kernel/jump_label.c:919
static_key_enable_cpuslocked+0x1b7/0x270 kernel/jump_label.c:210
static_key_enable+0x1a/0x20 kernel/jump_label.c:223
toggle_allocation_gate mm/kfence/core.c:850 [inline]
toggle_allocation_gate+0xfa/0x280 mm/kfence/core.c:842
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
process_scheduled_works kernel/workqueue.c:3321 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402
kthread+0x3c5/0x780 kernel/kthread.c:464
ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245