rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6620/3:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=15669, q=178 ncpus=2)
task:syz.0.143       state:R  running task     stack:27080 pid:6620  tgid:6617  ppid:5838   task_flags:0x40054c flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x23/0x80 kernel/kcov.c:217
Code: 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 08 40 f6 91 65 8b 35 d8 d1 37 10 81 e6 00 00 ff 00 ba 00 01 00 00 <23> 91 0c 0b 00 00 89 d7 09 f7 74 11 85 f6 75 39 85 d2 74 35 83 b9
RSP: 0018:ffffc90003dbf330 EFLAGS: 00000246
RAX: ffffffff82245aeb RBX: 0000000000000009 RCX: ffff88802f40bb80
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffff9400027da39 R12: 000000000004fb47
R13: dffffc0000000000 R14: ffff88813fffa740 R15: 0000000000001000
 __nr_to_section include/linux/mmzone.h:1944 [inline]
 __pfn_to_section include/linux/mmzone.h:2079 [inline]
 lookup_page_ext mm/page_ext.c:251 [inline]
 page_ext_lookup+0xab/0x180 mm/page_ext.c:509
 page_ext_iter_begin include/linux/page_ext.h:132 [inline]
 page_table_check_clear+0x278/0x700 mm/page_table_check.c:78
 ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline]
 get_and_clear_full_ptes include/linux/pgtable.h:725 [inline]
 zap_present_folio_ptes mm/memory.c:1499 [inline]
 zap_present_ptes mm/memory.c:1581 [inline]
 do_zap_pte_range mm/memory.c:1682 [inline]
 zap_pte_range mm/memory.c:1726 [inline]
 zap_pmd_range mm/memory.c:1818 [inline]
 zap_pud_range mm/memory.c:1847 [inline]
 zap_p4d_range mm/memory.c:1868 [inline]
 unmap_page_range+0x2ec0/0x3c10 mm/memory.c:1889
 unmap_single_vma mm/memory.c:1932 [inline]
 unmap_vmas+0x399/0x580 mm/memory.c:1976
 exit_mmap+0x248/0xb50 mm/mmap.c:1280
 __mmput+0xcb/0x3d0 kernel/fork.c:1129
 exit_mm+0x1da/0x2c0 kernel/exit.c:582
 do_exit+0x648/0x2300 kernel/exit.c:949
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
 get_signal+0x125e/0x1310 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc74e96eec9
RSP: 002b:00007fc74cbce0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fc74ebc5fa8 RCX: 00007fc74e96eec9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fc74ebc5fa8
RBP: 00007fc74ebc5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc74ebc6038 R14: 00007ffe88e5e290 R15: 00007ffe88e5e378
 </TASK>
rcu: rcu_preempt kthread starved for 10406 jiffies! g15669 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:26952 pid:18    tgid:18    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7058
 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+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x436/0x7d0 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: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: 13 b3 03 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 13 26 11 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8d607d80 EFLAGS: 000002c6
RAX: 967ca15220566f00 RBX: ffffffff81955f48 RCX: 967ca15220566f00
RDX: 0000000000000001 RSI: ffffffff8d03ad79 RDI: ffffffff8b621680
RBP: ffffffff8d607eb8 R08: ffff8880b883341b R09: 1ffff11017106683
R10: dffffc0000000000 R11: ffffed1017106684 R12: ffffffff8f1d6330
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1ae0620
FS:  0000000000000000(0000) GS:ffff8881268bc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31b05ff8 CR3: 0000000029834000 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:757
 default_idle_call+0x74/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:190 [inline]
 do_idle+0x1e8/0x510 kernel/sched/idle.c:330
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
 rest_init+0x2de/0x300 init/main.c:744
 start_kernel+0x3a9/0x410 init/main.c:1097
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:307
 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:288
 common_startup_64+0x13e/0x147
 </TASK>