syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5869/1:b..l P6805/3:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=16405, q=292 ncpus=2)
task:syz.4.212       state:R  running task     stack:25640 pid:6805  tgid:6802  ppid:5835   task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5257 [inline]
 __schedule+0x14bc/0x5030 kernel/sched/core.c:6864
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7048
 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7072
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 filemap_map_pages+0x192d/0x1ff0 mm/filemap.c:3931
 do_fault_around mm/memory.c:5713 [inline]
 do_read_fault mm/memory.c:5746 [inline]
 do_fault mm/memory.c:5889 [inline]
 do_pte_missing+0x20b3/0x3380 mm/memory.c:4401
 handle_pte_fault mm/memory.c:6273 [inline]
 __handle_mm_fault mm/memory.c:6411 [inline]
 handle_mm_fault+0x1b48/0x32c0 mm/memory.c:6580
 faultin_page mm/gup.c:1126 [inline]
 __get_user_pages+0x1650/0x29f0 mm/gup.c:1428
 populate_vma_page_range+0x29f/0x3a0 mm/gup.c:1860
 __mm_populate+0x24c/0x380 mm/gup.c:1963
 mm_populate include/linux/mm.h:3695 [inline]
 vm_mmap_pgoff+0x387/0x4d0 mm/util.c:586
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8859d8f749
RSP: 002b:00007f8857ff6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f8859fe5fa0 RCX: 00007f8859d8f749
RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007f8859e13f91 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8859fe6038 R14: 00007f8859fe5fa0 R15: 00007ffccaa82108
 </TASK>
task:kworker/1:3     state:R  running task     stack:23880 pid:5869  tgid:5869  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: events cleanup_vm_area_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5257 [inline]
 __schedule+0x14bc/0x5030 kernel/sched/core.c:6864
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7191
 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:debug_lockdep_rcu_enabled+0x16/0x40 kernel/rcu/update.c:320
Code: cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 31 c0 83 3d 67 ec 21 04 00 74 1e 83 3d 7a 1b 22 04 00 <74> 15 65 48 8b 0c 25 08 80 76 92 31 c0 83 b9 2c 0b 00 00 00 0f 94
RSP: 0018:ffffc9000427f5f0 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffffff818c189a RCX: 885a2108d4fd4400
RDX: 0000000000000000 RSI: ffffffff8d977664 RDI: ffffffff8bbf7760
RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff81745035
R10: ffffc9000427f718 R11: ffffffff81adcc30 R12: 1ffff9200084fed9
R13: ffffc9000427f700 R14: ffffc9000427f6c8 R15: ffffffff81745035
 rcu_read_lock include/linux/rcupdate.h:868 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0xcb/0x2390 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf5/0x1f0 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:1395 [inline]
 __free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943
 vfree+0x25a/0x400 mm/vmalloc.c:3466
 cleanup_vm_area_work+0xa2/0x100 mm/vmalloc.c:3763
 process_one_work+0x93a/0x15e0 kernel/workqueue.c:3261
 process_scheduled_works kernel/workqueue.c:3344 [inline]
 worker_thread+0x9f5/0xee0 kernel/workqueue.c:3425
 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: rcu_preempt kthread starved for 10567 jiffies! g16405 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:27272 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5257 [inline]
 __schedule+0x14bc/0x5030 kernel/sched/core.c:6864
 __schedule_loop kernel/sched/core.c:6946 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6961
 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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 33 40 0c 00 f3 0f 1e fa fb f4 <e9> c8 f2 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6
RAX: 3321c94f3f670e00 RBX: ffffffff8197a977 RCX: 3321c94f3f670e00
RDX: 0000000000000001 RSI: ffffffff8d790e8f RDI: ffffffff8bbf7760
RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db
R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8f7df370
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff110039dcb70
FS:  0000000000000000(0000) GS:ffff888125fb8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000513e8000 CR4: 00000000003526f0
DR0: 0000000000000008 DR1: 0000000000000002 DR2: 0000000000000404
DR3: ffffffffefffff14 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:767
 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:190 [inline]
 do_idle+0x1e7/0x510 kernel/sched/idle.c:330
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
 common_startup_64+0x13e/0x147
 </TASK>