rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=fc94/1/0x4000000000000000 softirq=76850/76857 fqs=1
rcu: 	(detected by 1, t=10506 jiffies, g=74473, q=258 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 16582 Comm: syz.4.3511 Not tainted 6.15.0-rc7-next-20250523-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:debug_spin_lock_after kernel/locking/spinlock_debug.c:94 [inline]
RIP: 0010:do_raw_spin_lock+0x155/0x290 kernel/locking/spinlock_debug.c:118
Code: 0f b1 0b 0f 85 dd 00 00 00 65 8b 1d 39 da fd 10 48 b9 00 00 00 00 00 fc ff df 41 0f b6 04 0f 49 89 cf 84 c0 0f 85 0b 01 00 00 <41> 89 5d 00 43 80 3c 3e 00 74 08 4c 89 e7 e8 98 e7 84 00 48 8b 44
RSP: 0018:ffffc90000007be0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000007c20
RBP: ffffc90000007c90 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000000f84 R12: ffff8880b8627ad0
R13: ffff8880b8627ac8 R14: 1ffff110170c4f5a R15: dffffc0000000000
FS:  00007ff8e49836c0(0000) GS:ffff888125c56000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff14c7eed58 CR3: 00000000775d4000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:120 [inline]
 _raw_spin_lock_irq+0xae/0xf0 kernel/locking/spinlock.c:170
 __run_hrtimer kernel/time/hrtimer.c:1765 [inline]
 __hrtimer_run_queues+0x602/0xc60 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:rcu_preempt_read_enter kernel/rcu/tree_plugin.h:391 [inline]
RIP: 0010:__rcu_read_lock+0x1c/0x60 kernel/rcu/tree_plugin.h:414
Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 53 65 48 8b 1c 25 08 a0 9c 92 48 81 c3 44 04 00 00 48 89 d8 48 c1 e8 03 <48> b9 00 00 00 00 00 fc ff df 0f b6 04 08 84 c0 75 18 ff 03 8b 03
RSP: 0018:ffffc9000cf8f028 EFLAGS: 00000a03
RAX: 1ffff110068fa808 RBX: ffff8880347d4044 RCX: b6e44575f0e69e00
RDX: dffffc0000000000 RSI: ffffffff822078f2 RDI: ffffc9000cf8f108
RBP: dffffc0000000000 R08: ffffc9000cf8f1d0 R09: 0000000000000003
R10: ffffc9000cf8f158 R11: ffffffff81ace0c0 R12: 1ffff920019f1e21
R13: ffffc9000cf8f140 R14: ffffc9000cf8f108 R15: ffffc9000cf8f7f8
 rcu_read_lock include/linux/rcupdate.h:839 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0x9e/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+0xf7/0x1f0 mm/page_owner.c:156
 __set_page_owner+0x8d/0x4a0 mm/page_owner.c:329
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2438
 shmem_alloc_folio mm/shmem.c:1851 [inline]
 shmem_alloc_and_add_folio+0x447/0xf60 mm/shmem.c:1890
 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2532
 shmem_get_folio mm/shmem.c:2638 [inline]
 shmem_write_begin+0xf7/0x2b0 mm/shmem.c:3288
 generic_perform_write+0x2c4/0x910 mm/filemap.c:4103
 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3463
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x548/0xa90 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff8e3b8d41f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48
RSP: 002b:00007ff8e4982df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007ff8e3b8d41f
RDX: 0000000001000000 RSI: 00007ff8d9400000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000000559d
R10: 000020000000e0c2 R11: 0000000000000293 R12: 0000000000000003
R13: 00007ff8e4982ef0 R14: 00007ff8e4982eb0 R15: 00007ff8d9400000
 </TASK>
rcu: rcu_preempt kthread starved for 10500 jiffies! g74473 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:27320 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6878
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 16578 Comm: syz.2.3509 Not tainted 6.15.0-rc7-next-20250523-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline]
RIP: 0010:smp_call_function_many_cond+0xe80/0x11c0 kernel/smp.c:885
Code: 00 00 00 00 00 fc ff df 75 07 e8 fb 73 0b 00 eb 37 f3 90 43 0f b6 04 2c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 e0 73 0b 00 <eb> e5 44 89 f9 80 e1 07 80 c1 03 38 c1 7c e3 4c 89 ff e8 39 dd 6e
RSP: 0018:ffffc9000d0ff580 EFLAGS: 00000246
RAX: ffffffff81b4cf50 RBX: ffff8880b873cb00 RCX: 0000000000080000
RDX: ffffc9000fe75000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc9000d0ff6e0 R08: ffffffff8fa12ef7 R09: 1ffffffff1f425de
R10: dffffc0000000000 R11: fffffbfff1f425df R12: 1ffff110170c86ad
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8643568
FS:  00007fa1a18606c0(0000) GS:ffff888125d56000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3291eff8 CR3: 0000000033aca000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
 flush_tlb_mm_range+0x6b1/0x12c0 arch/x86/mm/tlb.c:1451
 tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
 tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:480 [inline]
 tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403
 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:496
 vms_clear_ptes+0x42c/0x540 mm/vma.c:1231
 vms_complete_munmap_vmas+0x206/0x8a0 mm/vma.c:1273
 do_vmi_align_munmap+0x358/0x420 mm/vma.c:1532
 do_vmi_munmap+0x253/0x2e0 mm/vma.c:1580
 __vm_munmap+0x23b/0x3d0 mm/vma.c:3100
 __do_sys_munmap mm/mmap.c:1084 [inline]
 __se_sys_munmap mm/mmap.c:1081 [inline]
 __x64_sys_munmap+0x60/0x70 mm/mmap.c:1081
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa1a098e9f7
Code: 00 00 00 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 0b 00 00 00 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:00007fa1a185fe18 EFLAGS: 00000246 ORIG_RAX: 000000000000000b
RAX: ffffffffffffffda RBX: 00000000013bd7ef RCX: 00007fa1a098e9f7
RDX: 0000000000000000 RSI: 0000000008400000 RDI: 00007fa196200000
RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000054ff
R10: 00000000000003c8 R11: 0000000000000246 R12: 0000000000000003
R13: 00007fa1a185fef0 R14: 00007fa1a185feb0 R15: 00007fa196200000
 </TASK>