syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9020/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=35609, q=643 ncpus=2)
task:syz-executor.5  state:R  running task     stack:23800 pid:9020  tgid:9019  ppid:8007   flags:0x00000002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0x17e8/0x4a20 kernel/sched/core.c:6745
 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7067
 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:rcu_read_lock include/linux/rcupdate.h:782 [inline]
RIP: 0010:__fget_files+0x4d/0x470 fs/file.c:1035
Code: 8d 05 00 00 00 00 48 c7 c7 a0 3f 33 8e 31 f6 31 d2 b9 02 00 00 00 45 31 c0 45 31 c9 48 89 04 24 50 e8 47 2f 5d ff 48 83 c4 08 <e8> 8e a7 70 09 89 c3 31 ff 89 c6 e8 03 f4 80 ff 85 db 74 10 e8 7a
RSP: 0018:ffffc9000372fe38 EFLAGS: 00000282
RAX: 6c00d75af4edf300 RBX: ffff88802dced2c0 RCX: 0000000000000001
RDX: dffffc0000000000 RSI: ffffffff8bcacce0 RDI: ffffffff8c1feb40
RBP: 0000000000000002 R08: ffffffff92fa7587 R09: 1ffffffff25f4eb0
R10: dffffc0000000000 R11: fffffbfff25f4eb1 R12: dffffc0000000000
R13: 0000000000000005 R14: ffff88802dced2c0 R15: 0000000000000005
 __fget_light fs/file.c:1151 [inline]
 __fdget+0x16c/0x1e0 fs/file.c:1159
 fdget include/linux/file.h:66 [inline]
 __do_sys_tee fs/splice.c:2018 [inline]
 __se_sys_tee fs/splice.c:2006 [inline]
 __x64_sys_tee+0xc0/0x1b0 fs/splice.c:2006
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa449e7d0a9
RSP: 002b:00007fa44acb70c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000114
RAX: ffffffffffffffda RBX: 00007fa449fb3f80 RCX: 00007fa449e7d0a9
RDX: 0000000000000003 RSI: 0000000000000004 RDI: 0000000000000005
RBP: 00007fa449eec074 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fa449fb3f80 R15: 00007ffe5a829ee8
 </TASK>
rcu: rcu_preempt kthread starved for 10528 jiffies! g35609 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:26448 pid:17    tgid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0x17e8/0x4a20 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6837
 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2581
 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2000
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2202
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 1052 Comm: kworker/u8:6 Not tainted 6.10.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:311 [inline]
RIP: 0010:smp_call_function_many_cond+0x1865/0x29d0 kernel/smp.c:855
Code: 89 e6 83 e6 01 31 ff e8 f9 09 0c 00 41 83 e4 01 49 bc 00 00 00 00 00 fc ff df 75 07 e8 a4 05 0c 00 eb 38 f3 90 42 0f b6 04 23 <84> c0 75 11 41 f7 45 00 01 00 00 00 74 1e e8 88 05 0c 00 eb e4 44
RSP: 0018:ffffc900042b7700 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 1ffff11017288c01 RCX: ffff888021eabc00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900042b78e0 R08: ffffffff818a1fd7 R09: 1ffffffff25f4eb0
R10: dffffc0000000000 R11: fffffbfff25f4eb1 R12: dffffc0000000000
R13: ffff8880b9446008 R14: ffff8880b953f8c0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33524000 CR3: 000000000e132000 CR4: 0000000000350ef0
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1023
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:2069 [inline]
 text_poke_bp_batch+0x352/0xb30 arch/x86/kernel/alternative.c:2279
 text_poke_flush arch/x86/kernel/alternative.c:2470 [inline]
 text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2477
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 static_key_disable_cpuslocked+0xce/0x1c0 kernel/jump_label.c:235
 static_key_disable+0x1a/0x20 kernel/jump_label.c:243
 toggle_allocation_gate+0x1b8/0x250 mm/kfence/core.c:831
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xa2e/0x1830 kernel/workqueue.c:3312
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3393
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>