rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P17719/1:b..l
	(detected by 1, t=10502 jiffies, g=113497, q=56 ncpus=2)
task:syz.6.4073      state:R  running task     stack:23120 pid:17719 ppid:15515  flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6875
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:212
Code: 2e 0f 1f 84 00 00 00 00 00 90 53 48 89 fb e8 17 00 00 00 48 8b 3d 00 df 9e 0c 48 89 de 5b e9 77 62 50 00 00 00 cc cc 00 00 cc <48> 8b 04 24 65 48 8b 0d 14 41 80 7e 65 8b 15 15 41 80 7e 81 e2 00
RSP: 0018:ffffc900033a72f0 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffffff81dd9aae RCX: cdb5a38c656f7400
RDX: ffff888030443c00 RSI: ffffffff8adf5dc0 RDI: ffffffff8adf5d80
RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff2162048
R10: dffffc0000000000 R11: fffffbfff2162049 R12: 00fff00000000000
R13: dffffc0000000000 R14: ffffea0001090800 R15: ffffea0001090800
 rcu_read_lock include/linux/rcupdate.h:792 [inline]
 page_ext_get+0x60/0x2a0 mm/page_ext.c:157
 __page_table_check_zero+0x134/0x4b0 mm/page_table_check.c:146
 prep_new_page mm/page_alloc.c:2567 [inline]
 get_page_from_freelist+0x206b/0x2180 mm/page_alloc.c:4358
 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5658
 __folio_alloc+0xe/0x30 mm/page_alloc.c:5690
 vma_alloc_folio+0x499/0x900 mm/mempolicy.c:2243
 shmem_alloc_folio mm/shmem.c:1589 [inline]
 shmem_alloc_and_acct_folio+0x463/0xbd0 mm/shmem.c:1613
 shmem_get_folio_gfp+0x1439/0x35e0 mm/shmem.c:1941
 shmem_get_folio mm/shmem.c:2072 [inline]
 shmem_write_begin+0xee/0x3f0 mm/shmem.c:2556
 generic_perform_write+0x2fa/0x5c0 mm/filemap.c:3862
 __generic_file_write_iter+0x148/0x2a0 mm/filemap.c:3960
 generic_file_write_iter+0xab/0x2e0 mm/filemap.c:3989
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x482/0x9a0 fs/read_write.c:584
 ksys_write+0x14d/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe38f15e84e
RSP: 002b:00007fe390158da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fe3901596c0 RCX: 00007fe38f15e84e
RDX: 0000000004000000 RSI: 00007fe384ff7000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007fe390158ee0 R14: 00007fe390158ea0 R15: 00007fe384ff7000
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10539 jiffies! g113497 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=59906
rcu: rcu_preempt kthread starved for 10545 jiffies! g113497 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27888 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 schedule+0xb9/0x180 kernel/sched/core.c:6639
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x303/0x1350 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 17723 Comm: syz.1.4075 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: 00 00 00 66 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 ae 45 2a f7 48 89 df e8 36 0d 2b f7 e8 21 5e 4e f7 fb bf 01 00 00 00 <e8> b6 88 1e f7 65 8b 05 27 3a c8 75 85 c0 74 02 5b c3 e8 34 4e c6
RSP: 0018:ffffc90003327b98 EFLAGS: 00000282
RAX: 248040582a902300 RBX: ffff88806283dc80 RCX: 248040582a902300
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: 0000000000000001
RBP: 0000000000000000 R08: ffff88806283dc83 R09: 1ffff1100c507b90
R10: dffffc0000000000 R11: ffffed100c507b91 R12: 0000000000000021
R13: ffff88806283e118 R14: dffffc0000000000 R15: 000000001c000004
FS:  00007f9885f436c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 000000002859d000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 get_signal+0x114a/0x1340 kernel/signal.c:2883
 arch_do_signal_or_restart+0xc4/0x1310 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9884f9e017
Code: 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 <0f> 05 48 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89
RSP: 002b:00007f9885f430e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007f9885225fa8 RCX: 00007f9884f9e019
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f9885225fa8
RBP: 00007f9885225fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9885226038 R14: 00007ffef9f0e000 R15: 00007ffef9f0e0e8
 </TASK>