rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P10578/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=40165, q=131 ncpus=2)
task:syz.5.1223      state:R  running task     stack:24840 pid:10578 ppid:6887   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:check_kcov_mode kernel/kcov.c:184 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x30/0x60 kernel/kcov.c:216
Code: 04 24 65 48 8b 0d 20 28 7e 7e 65 8b 15 21 28 7e 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c <8b> 91 f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48
RSP: 0018:ffffc9000b8b74f0 EFLAGS: 00000246
RAX: ffffffff81e7afae RBX: 0000000000000001 RCX: ffff888030a69e00
RDX: 0000000000000000 RSI: 0000000000027b04 RDI: 0000000000027b05
RBP: dffffc0000000000 R08: ffff88801a4166df R09: 1ffff11003482cdb
R10: dffffc0000000000 R11: ffffed1003482cdc R12: ffff88801a4166dc
R13: 1ffffffff2de332c R14: ffff88801a4166e0 R15: 0000000000000000
 __page_table_check_zero+0x17e/0x4b0 mm/page_table_check.c:153
 prep_new_page mm/page_alloc.c:1561 [inline]
 get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191
 __alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457
 __folio_alloc+0x10/0x20 mm/page_alloc.c:4489
 vma_alloc_folio+0x47a/0x8f0 mm/mempolicy.c:2242
 mfill_atomic_pte_copy+0x8e/0x430 mm/userfaultfd.c:153
 mfill_atomic_pte mm/userfaultfd.c:587 [inline]
 mfill_atomic mm/userfaultfd.c:727 [inline]
 mfill_atomic_copy+0x75f/0x1690 mm/userfaultfd.c:778
 userfaultfd_copy fs/userfaultfd.c:1782 [inline]
 userfaultfd_ioctl+0x1dbc/0x4f10 fs/userfaultfd.c:2119
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fec43d8f6c9
RSP: 002b:00007fec44b96038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fec43fe5fa0 RCX: 00007fec43d8f6c9
RDX: 0000200000000000 RSI: 00000000c028aa03 RDI: 0000000000000003
RBP: 00007fec43e11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fec43fe6038 R14: 00007fec43fe5fa0 R15: 00007ffeb3b75c58
 </TASK>
rcu: rcu_preempt kthread starved for 10529 jiffies! g40165 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:26728 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </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: 0 Comm: swapper/1 Not tainted syzkaller #0
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:148
Code: cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d c3 64 39 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56
RSP: 0018:ffffc90000187de0 EFLAGS: 000002c2
RAX: 6edeb1abbf170600 RBX: ffffffff816187ab RCX: 6edeb1abbf170600
RDX: 0000000000000001 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6b00
RBP: ffffc90000187f20 R08: ffff8880b8f36b2b R09: 1ffff110171e6d65
R10: dffffc0000000000 R11: ffffed10171e6d66 R12: ffffffff8e4a8d68
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff1100374c780
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3ca4e534f8 CR3: 000000002f449000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:753
 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
 cpuidle_idle_call kernel/sched/idle.c:170 [inline]
 do_idle+0x1eb/0x510 kernel/sched/idle.c:282
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
 start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323
 secondary_startup_64_no_verify+0x179/0x17b
 </TASK>