rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9645/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=34665, q=267 ncpus=2)
task:syz.4.1017      state:R  running task     stack:25960 pid:9645  tgid:9638  ppid:5827   task_flags:0x400040 flags:0x00080003
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5254 [inline]
 __schedule+0x17c4/0x4d60 kernel/sched/core.c:6862
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7189
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:rcu_is_watching+0x0/0xb0 kernel/rcu/tree.c:747
Code: c7 c7 e0 01 f4 8d e8 9f 67 1f 03 eb cc 66 66 66 66 2e 0f 1f 84 00 00 00 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 53 65 ff 05 50 4c cd 10 e8 ab b8 af 09 89
RSP: 0018:ffffc90003cbece8 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffffffff901a3401 RCX: 06f697939a09b900
RDX: ffffc90003cbee01 RSI: ffffffff8173d0d5 RDI: ffffffff8df3b360
RBP: dffffc0000000000 R08: ffffc90003cbf148 R09: 0000000000000000
R10: ffffc90003cbee78 R11: fffff52000797dd1 R12: ffffc90003cbf158
R13: ffffffff8173d0d5 R14: ffffffff8df3b360 R15: ffffffff8173d0d5
 trace_lock_release include/trace/events/lock.h:69 [inline]
 lock_release+0x4b/0x3e0 kernel/locking/lockdep.c:5879
 rcu_lock_release include/linux/rcupdate.h:341 [inline]
 rcu_read_unlock include/linux/rcupdate.h:897 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680
 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
 __set_page_owner+0x8d/0x4c0 mm/page_owner.c:341
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3920
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5214
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2479
 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2498
 shmem_alloc_folio mm/shmem.c:1900 [inline]
 shmem_alloc_and_add_folio+0x423/0xf40 mm/shmem.c:1942
 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2565
 shmem_fault+0x179/0x390 mm/shmem.c:2766
 __do_fault+0x138/0x390 mm/memory.c:5325
 do_read_fault mm/memory.c:5760 [inline]
 do_fault mm/memory.c:5894 [inline]
 do_pte_missing mm/memory.c:4406 [inline]
 handle_pte_fault mm/memory.c:6239 [inline]
 __handle_mm_fault+0x35dc/0x5440 mm/memory.c:6381
 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6550
 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:3549 [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: 0033:0x7fe2b698f6c9
RSP: 002b:00007fe2b78be038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fe2b6be6090 RCX: 00007fe2b698f6c9
RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007fe2b6a11f91 R08: ffffffffffffffff R09: 00000000c931e000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe2b6be6128 R14: 00007fe2b6be6090 R15: 00007fff8aaaba78
 </TASK>
rcu: rcu_preempt kthread starved for 10331 jiffies! g34665 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:26408 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5254 [inline]
 __schedule+0x17c4/0x4d60 kernel/sched/core.c:6862
 __schedule_loop kernel/sched/core.c:6944 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6959
 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+0x52d/0xa70 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:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: 83 eb 02 00 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 a3 89 11 00 f3 0f 1e fa fb f4 <e9> 58 eb 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8dc07d80 EFLAGS: 000002c6
RAX: 7289b745bcb88d00 RBX: ffffffff81972167 RCX: 7289b745bcb88d00
RDX: 0000000000000001 RSI: ffffffff8d783b86 RDI: ffffffff8bbf28c0
RBP: ffffffff8dc07ea8 R08: ffff8880b863321b R09: 1ffff110170c6643
R10: dffffc0000000000 R11: ffffed10170c6644 R12: ffffffff8f7d7570
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1b92660
FS:  0000000000000000(0000) GS:ffff888125eda000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f68d935b6c6 CR3: 000000007c8fa000 CR4: 00000000003526f0
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
 rest_init+0x2de/0x300 init/main.c:758
 start_kernel+0x3ac/0x410 init/main.c:1208
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x147
 </TASK>