syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P10210/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=627653, q=3037 ncpus=2)
task:syz.9.19899     state:R  running task     stack:27480 pid:10210 tgid:10202 ppid:23668  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5504 [inline]
 __schedule+0x17d9/0x56c0 kernel/sched/core.c:7228
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7552
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
 irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:__rcu_read_unlock+0x0/0xe0 kernel/rcu/tree_plugin.h:431
Code: d9 80 e1 07 80 c1 03 38 c1 7c dc 48 89 df e8 97 8f 87 00 eb d2 0f 1f 44 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 49 bf 00 00 00 00 00 fc ff
RSP: 0018:ffffc9000818f2b8 EFLAGS: 00000286
RAX: 733fe50436105200 RBX: ffffc9000818f378 RCX: 0000000080000001
RDX: ffffc9000818f301 RSI: ffffffff8c292100 RDI: ffffffff8c2920c0
RBP: 1ffffffff21a6a01 R08: ffffc9000818f810 R09: 0000000000000000
R10: ffffc9000818f3b8 R11: fffff52001031e79 R12: ffffc90008188000
R13: ffffffff8176a21f R14: ffffc9000818f368 R15: ffffc9000818f820
 rcu_read_unlock include/linux/rcupdate.h:873 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1183 [inline]
 unwind_next_frame+0x1baf/0x2550 arch/x86/kernel/unwind_orc.c:709
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 save_stack+0x122/0x230 mm/page_owner.c:165
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc0d/0xd20 mm/page_alloc.c:2938
 __slab_free+0x274/0x2c0 mm/slub.c:5672
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_kmalloc+0x22/0xb0 mm/kasan/common.c:406
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5334 [inline]
 __kmalloc_noprof+0x358/0x750 mm/slub.c:5347
 _kmalloc_noprof include/linux/slab.h:973 [inline]
 _kzalloc_noprof include/linux/slab.h:1286 [inline]
 iter_file_splice_write+0x1ea/0x1240 fs/splice.c:678
 do_splice_from fs/splice.c:936 [inline]
 direct_splice_actor+0x101/0x160 fs/splice.c:1159
 splice_direct_to_actor+0x57b/0xcb0 fs/splice.c:1103
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x195/0x290 fs/splice.c:1228
 do_sendfile+0x52e/0x7c0 fs/read_write.c:1371
 __do_sys_sendfile64 fs/read_write.c:1432 [inline]
 __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1418
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2555f9ce59
RSP: 002b:00007f2556ed5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f2556216180 RCX: 00007f2555f9ce59
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000007
RBP: 00007f2556032e6f R08: 0000000000000000 R09: 0000000000000000
R10: 000000007fffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2556216218 R14: 00007f2556216180 R15: 00007f255633fa48
 </TASK>
rcu: rcu_preempt kthread starved for 257 jiffies! g627653 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:28408 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5504 [inline]
 __schedule+0x17d9/0x56c0 kernel/sched/core.c:7228
 __schedule_loop kernel/sched/core.c:7307 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7322
 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123
 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325
 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
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 19204 Comm: kworker/u8:27 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0x10b0/0x14b0 kernel/smp.c:892
Code: c0 75 73 41 8b 1e 89 de 83 e6 01 31 ff e8 28 1d 0c 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 07 e8 d4 18 0c 00 eb 37 f3 90 <41> 0f b6 04 1c 84 c0 75 10 41 f7 06 01 00 00 00 74 1e e8 b9 18 0c
RSP: 0018:ffffc90006a9f720 EFLAGS: 00000293
RAX: ffffffff81ba0887 RBX: dffffc0000000000 RCX: ffff888077290000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90006a9f860 R08: ffffffff903147f7 R09: 1ffffffff20628fe
R10: dffffc0000000000 R11: fffffbfff20628ff R12: 1ffff110170e8199
R13: ffff8880b863c2c8 R14: ffff8880b8740cc8 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff888125269000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd932016038 CR3: 000000000e746000 CR4: 00000000003526f0
DR0: 0000000000000004 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 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:2773 [inline]
 smp_text_poke_batch_finish+0x5fd/0x1110 arch/x86/kernel/alternative.c:2983
 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:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 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
 </TASK>