rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P28127/1:b..l rcu: (detected by 1, t=10502 jiffies, g=394693, q=207 ncpus=2) task:syz.2.3532 state:R running task stack:25488 pid:28127 tgid:28126 ppid:27003 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x1800/0x4a60 kernel/sched/core.c:6529 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:6851 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x264/0x550 kernel/locking/lockdep.c:5763 Code: 2b 00 74 08 4c 89 f7 e8 5a 06 8b 00 f6 44 24 61 02 0f 85 85 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc90003b57140 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff9200076ae34 RCX: 6c0b3cc183c82d00 RDX: dffffc0000000000 RSI: ffffffff8c0ae6e0 RDI: ffffffff8c608f40 RBP: ffffc90003b57298 R08: ffffffff941e4847 R09: 1ffffffff283c908 R10: dffffc0000000000 R11: fffffbfff283c909 R12: 1ffff9200076ae30 R13: dffffc0000000000 R14: ffffc90003b571a0 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:326 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] page_ext_get+0x3d/0x2a0 mm/page_ext.c:525 __page_table_check_zero+0xb1/0x350 mm/page_table_check.c:148 page_table_check_alloc include/linux/page_table_check.h:33 [inline] post_alloc_hook+0x206/0x230 mm/page_alloc.c:1501 prep_new_page mm/page_alloc.c:1508 [inline] get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3446 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4702 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2263 folio_alloc_mpol_noprof+0x36/0x50 mm/mempolicy.c:2281 shmem_alloc_folio mm/shmem.c:1722 [inline] shmem_alloc_and_add_folio+0x2cf/0x14f0 mm/shmem.c:1782 shmem_get_folio_gfp+0x8dc/0x2370 mm/shmem.c:2188 shmem_get_folio mm/shmem.c:2293 [inline] shmem_write_begin+0x170/0x4d0 mm/shmem.c:2898 generic_perform_write+0x39b/0x840 mm/filemap.c:4019 shmem_file_write_iter+0xfc/0x120 mm/shmem.c:3074 new_sync_write fs/read_write.c:497 [inline] vfs_write+0xa74/0xc90 fs/read_write.c:590 ksys_write+0x1a0/0x2c0 fs/read_write.c:643 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcac4d7c9df RSP: 002b:00007fcac4bf7df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00000000013bd7ef RCX: 00007fcac4d7c9df RDX: 00000000013bd7ef RSI: 00007fcaba200000 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000005535 R10: 000000002000ac02 R11: 0000000000000293 R12: 0000000000000003 R13: 00007fcac4bf7ef0 R14: 00007fcac4bf7eb0 R15: 00007fcaba200000 rcu: rcu_preempt kthread starved for 10501 jiffies! g394693 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:25744 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x1800/0x4a60 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6621 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2581 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2034 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2236 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline] NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:111