rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P19402/1:b..l rcu: (detected by 0, t=10502 jiffies, g=92917, q=457 ncpus=2) task:syz.1.5614 state:R running task stack:24552 pid:19402 tgid:19401 ppid:18274 task_flags:0x400040 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5392 [inline] __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6781 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7104 irqentry_exit+0x6f/0x90 kernel/entry/common.c:307 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:orc_ip arch/x86/kernel/unwind_orc.c:80 [inline] RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:102 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:227 [inline] RIP: 0010:unwind_next_frame+0x1315/0x2390 arch/x86/kernel/unwind_orc.c:494 Code: 83 e0 fe 4c 8d 3c 45 00 00 00 00 49 01 ef 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 84 c0 75 27 49 63 07 <4c> 01 f8 49 8d 4f 04 4c 39 e0 48 0f 46 e9 49 8d 47 fc 48 0f 47 d8 RSP: 0018:ffffc90003a2ecb8 EFLAGS: 00000246 RAX: fffffffff24e7704 RBX: ffffffff8fbaba34 RCX: dffffc0000000000 RDX: ffffffff8fbaba34 RSI: ffffffff90399164 RDI: ffffffff8be19020 RBP: ffffffff8fbaba34 R08: 0000000000000001 R09: ffffffff81724865 R10: ffffc90003a2edd8 R11: ffffffff81ac9840 R12: ffffffff820968f4 R13: ffffffff8fbaba34 R14: ffffc90003a2ed88 R15: ffffffff8fbaba34 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf7/0x1f0 mm/page_owner.c:156 __set_page_owner+0x8d/0x4a0 mm/page_owner.c:329 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1710 prep_new_page mm/page_alloc.c:1718 [inline] get_page_from_freelist+0x21d1/0x22b0 mm/page_alloc.c:3680 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4970 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2301 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2320 shmem_alloc_folio mm/shmem.c:1850 [inline] shmem_alloc_and_add_folio+0x447/0xf60 mm/shmem.c:1889 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2529 shmem_fault+0x179/0x390 mm/shmem.c:2730 __do_fault+0x138/0x390 mm/memory.c:5098 do_read_fault mm/memory.c:5518 [inline] do_fault mm/memory.c:5652 [inline] do_pte_missing mm/memory.c:4160 [inline] handle_pte_fault mm/memory.c:5997 [inline] __handle_mm_fault+0x37c5/0x55e0 mm/memory.c:6140 handle_mm_fault+0x2d5/0x7f0 mm/memory.c:6309 faultin_page mm/gup.c:1193 [inline] __get_user_pages+0x1a78/0x30c0 mm/gup.c:1491 populate_vma_page_range+0x26b/0x340 mm/gup.c:1929 __mm_populate+0x24c/0x380 mm/gup.c:2032 mm_populate include/linux/mm.h:3487 [inline] vm_mmap_pgoff+0x3f0/0x4c0 mm/util.c:584 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fce8238e969 RSP: 002b:00007fce801f6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007fce825b5fa0 RCX: 00007fce8238e969 RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007fce82410ab1 R08: ffffffffffffffff R09: 00000000a2bb1000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fce825b5fa0 R15: 00007ffe248ea968 rcu: rcu_preempt kthread starved for 10494 jiffies! g92917 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:27320 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5392 [inline] __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6781 __schedule_loop kernel/sched/core.c:6859 [inline] schedule+0x165/0x360 kernel/sched/core.c:6874 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 5819 Comm: syz-executor Not tainted 6.15.0-syzkaller-07774-g90b83efa6701 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0xe69/0x11c0 kernel/smp.c:885 Code: 00 45 8b 2f 44 89 ee 83 e6 01 31 ff e8 a0 77 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 4b 73 0b 00 eb 37 f3 90 <43> 0f b6 04 2c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 30 73 0b RSP: 0018:ffffc9000491f5c0 EFLAGS: 00000293 RAX: ffffffff81b486d0 RBX: ffff8880b863ca80 RCX: ffff88806d0a1e00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000491f720 R08: ffffffff8f9f87b7 R09: 1ffffffff1f3f0f6 R10: dffffc0000000000 R11: fffffbfff1f3f0f7 R12: 1ffff110170e8241 R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8880b8741208 FS: 0000555587e8f500(0000) GS:ffff888125c98000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f269b0e56c0 CR3: 0000000063478000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x6b1/0x12c0 arch/x86/mm/tlb.c:1451 dup_mmap kernel/fork.c:766 [inline] dup_mm kernel/fork.c:1737 [inline] copy_mm+0x18e2/0x2160 kernel/fork.c:1789 copy_process+0x1706/0x3c00 kernel/fork.c:2429 kernel_clone+0x224/0x7f0 kernel/fork.c:2859 __do_sys_clone kernel/fork.c:3002 [inline] __se_sys_clone kernel/fork.c:2986 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2986 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f269a3851d3 Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffc0e3998c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f269a3851d3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 0000555587e8f7d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 0000000000081b1e R15: 00007ffc0e399a60