syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=0b2c/1/0x4000000000000000 softirq=37393/37396 fqs=1
rcu: 	(detected by 1, t=10502 jiffies, g=30781, q=552 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 8937 Comm: syz.3.653 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__lock_acquire+0xff/0x2cf0 kernel/locking/lockdep.c:5141
Code: 93 c6 40 20 ce 40 80 fe 01 0f 84 21 01 00 00 8b 9c 24 40 01 00 00 44 8b a4 24 30 01 00 00 89 d5 48 c7 c1 b0 73 48 93 48 29 c8 <48> c1 f8 03 48 be 29 5c 8f c2 f5 28 5c 8f 48 0f af f0 85 db 0f 85
RSP: 0018:ffffc90000007a38 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff934873b0
RDX: 0000000000000003 RSI: 0000000000000000 RDI: ffffffff99d94238
RBP: 0000000000000003 R08: 0000000000000001 R09: ffffffff99d94238
R10: ffff88803035f308 R11: ffffed100606be63 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
FS:  00007f156c1706c0(0000) GS:ffff888125c25000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000001ba98000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
 debug_object_deactivate+0x6d/0x360 lib/debugobjects.c:873
 debug_hrtimer_deactivate kernel/time/hrtimer.c:443 [inline]
 debug_deactivate+0x1d/0x1e0 kernel/time/hrtimer.c:483
 __run_hrtimer kernel/time/hrtimer.c:1745 [inline]
 __hrtimer_run_queues+0x2b0/0xc30 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
 __sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:free_vmap_area_rb_augment_cb_compute_max mm/vmalloc.c:1096 [inline]
RIP: 0010:free_vmap_area_rb_augment_cb_propagate mm/vmalloc.c:1096 [inline]
RIP: 0010:augment_tree_propagate_from mm/vmalloc.c:1425 [inline]
RIP: 0010:va_clip mm/vmalloc.c:1830 [inline]
RIP: 0010:va_alloc+0xd84/0xef0 mm/vmalloc.c:1858
Code: 00 4d 8b 36 4d 85 f6 74 2a e8 28 70 a9 ff 49 83 c6 28 4c 89 f0 48 c1 e8 03 80 3c 18 00 74 08 4c 89 f7 e8 8f 18 10 00 49 8b 06 <4c> 39 e8 4c 0f 47 e8 eb 05 e8 fe 6f a9 ff 49 89 ec 4d 8d 77 28 4c
RSP: 0018:ffffc90004c373b0 EFLAGS: 00000246
RAX: 0000000000028000 RBX: dffffc0000000000 RCX: 0000000000080000
RDX: ffffc9000dc59000 RSI: 000000000000045b RDI: 000000000000045c
RBP: ffff8880354d01b0 R08: ffff888020311e80 R09: 0000000000000004
R10: 0000000000000004 R11: 0000000000000002 R12: ffffc900162fe000
R13: 000000000055d000 R14: ffff88802f91e4b0 R15: ffff8880354d01b0
 __alloc_vmap_area mm/vmalloc.c:1894 [inline]
 alloc_vmap_area+0x99f/0x14e0 mm/vmalloc.c:2112
 __get_vm_area_node+0x1f8/0x300 mm/vmalloc.c:3257
 __vmalloc_node_range_noprof+0x371/0x16a0 mm/vmalloc.c:4049
 vmalloc_user_noprof+0xad/0xf0 mm/vmalloc.c:4243
 vb2_vmalloc_alloc+0xef/0x360 drivers/media/common/videobuf2/videobuf2-vmalloc.c:47
 __vb2_buf_mem_alloc drivers/media/common/videobuf2/videobuf2-core.c:242 [inline]
 __vb2_queue_alloc+0x9c2/0x15a0 drivers/media/common/videobuf2/videobuf2-core.c:523
 vb2_core_reqbufs+0xc31/0x1420 drivers/media/common/videobuf2/videobuf2-core.c:958
 v4l2_m2m_reqbufs drivers/media/v4l2-core/v4l2-mem2mem.c:576 [inline]
 v4l2_m2m_ioctl_reqbufs+0x10d/0x200 drivers/media/v4l2-core/v4l2-mem2mem.c:1359
 __video_do_ioctl+0xa59/0xc10 drivers/media/v4l2-core/v4l2-ioctl.c:3131
 video_usercopy+0x82a/0x13f0 drivers/media/v4l2-core/v4l2-ioctl.c:3473
 v4l2_ioctl+0x18d/0x1e0 drivers/media/v4l2-core/v4l2-dev.c:366
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f156b38f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f156c170038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f156b5e6090 RCX: 00007f156b38f749
RDX: 00002000000001c0 RSI: 00000000c0145608 RDI: 0000000000000005
RBP: 00007f156b413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f156b5e6128 R14: 00007f156b5e6090 R15: 00007ffc223d55b8
 </TASK>
rcu: rcu_preempt kthread starved for 10495 jiffies! g30781 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:27168 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5258 [inline]
 __schedule+0x150e/0x5070 kernel/sched/core.c:6866
 __schedule_loop kernel/sched/core.c:6948 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6963
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 13 Comm: kworker/u8:1 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xccf/0x12b0 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 aa a6 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 55 a2 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 39 a2
RSP: 0018:ffffc90000127660 EFLAGS: 00000293
RAX: ffffffff81b61627 RBX: 1ffff110170c85d1 RCX: ffff88801d2f0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900001277e0 R08: ffffffff8fa22f77 R09: 1ffffffff1f445ee
R10: dffffc0000000000 R11: fffffbfff1f445ef R12: ffff8880b8642e88
R13: dffffc0000000000 R14: ffff8880b873bd40 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125d25000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000558f8b412218 CR3: 000000000df38000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
 on_each_cpu include/linux/smp.h:71 [inline]
 smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2711 [inline]
 smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2921
 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+0xad/0x240 mm/kfence/core.c:874
 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
 process_scheduled_works kernel/workqueue.c:3362 [inline]
 worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>