rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7393/1:b..l rcu: (detected by 1, t=10502 jiffies, g=14885, q=1080 ncpus=2) task:syz.1.289 state:R running task stack:26440 pid:7393 tgid:7387 ppid:5805 task_flags:0x400040 flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6929 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7256 irqentry_exit+0x36/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:unwind_next_frame+0xfe7/0x20a0 arch/x86/kernel/unwind_orc.c:664 Code: 85 80 0c 00 00 49 89 6d 40 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e 56 10 00 00 <41> 39 5d 00 0f 84 10 06 00 00 bd 01 00 00 00 e9 de f3 ff ff 48 b8 RSP: 0018:ffffc9001c4eecd0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffc9001c4f0000 RDX: 1ffff9200389dda8 RSI: ffffc9001c4ef470 RDI: ffffc9001c4eed80 RBP: 1ffff9200389de93 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 00000000000122c7 R12: ffffc9001c4eed90 R13: ffffc9001c4eed40 R14: ffffc9001c4ef498 R15: ffffc9001c4eed74 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x160/0x1f0 mm/page_owner.c:156 __set_page_owner+0x91/0x550 mm/page_owner.c:329 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5183 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 folio_alloc_mpol_noprof+0x36/0x2f0 mm/mempolicy.c:2435 vma_alloc_folio_noprof+0xed/0x1e0 mm/mempolicy.c:2470 folio_prealloc mm/memory.c:1189 [inline] wp_page_copy mm/memory.c:3679 [inline] do_wp_page+0x11d8/0x52b0 mm/memory.c:4140 handle_pte_fault mm/memory.c:6193 [inline] __handle_mm_fault+0x1ae3/0x2aa0 mm/memory.c:6318 handle_mm_fault+0x589/0xd10 mm/memory.c:6487 do_user_addr_fault+0x7a6/0x1370 arch/x86/mm/fault.c:1387 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x64/0xc0 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0010:__put_user_nocheck_4+0x3/0x10 arch/x86/lib/putuser.S:104 Code: d9 0f 01 cb 89 01 31 c9 0f 01 ca c3 cc cc cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 01 cb <89> 01 31 c9 0f 01 ca e9 d1 82 03 00 90 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc9001c4ef9e8 EFLAGS: 00050246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00002000000f1030 RDX: 0000000000080000 RSI: ffffffff892df3a3 RDI: 0000000000000005 RBP: ffffc9001c4efd88 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000000 R13: 00002000000f1000 R14: ffffc9001c4efdcc R15: 0000000000000002 ____sys_recvmsg+0x2ee/0x6b0 net/socket.c:2863 ___sys_recvmsg+0x114/0x1a0 net/socket.c:2892 do_recvmmsg+0x2fe/0x750 net/socket.c:2987 __sys_recvmmsg net/socket.c:3061 [inline] __do_sys_recvmmsg net/socket.c:3084 [inline] __se_sys_recvmmsg net/socket.c:3077 [inline] __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3077 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f44af58eec9 RSP: 002b:00007f44b03a8038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f44af7e6090 RCX: 00007f44af58eec9 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000006 RBP: 00007f44af611f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f44af7e6128 R14: 00007f44af7e6090 R15: 00007ffe23d1c7e8 rcu: rcu_preempt kthread starved for 9132 jiffies! g14885 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:28360 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7026 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: f7 74 02 c3 cc cc cc cc 0f 1f 00 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 43 05 24 00 fb f4 3c 0a 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff8e007df8 EFLAGS: 000002c6 RAX: 0000000000aadf31 RBX: 0000000000000000 RCX: ffffffff8b6622a9 RDX: 0000000000000000 RSI: ffffffff8db032ec RDI: ffffffff8bf1e3c0 RBP: fffffbfff1c12f40 R08: 0000000000000001 R09: ffffed1017086655 R10: ffff8880b84332ab R11: 0000000000000001 R12: 0000000000000000 R13: ffffffff8e097a00 R14: ffffffff90832dd0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881249d9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000556409021be0 CR3: 000000005c884000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x38d/0x500 kernel/sched/idle.c:330 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428 rest_init+0x16b/0x2b0 init/main.c:757 start_kernel+0x3f6/0x4e0 init/main.c:1111 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x148 vkms_vblank_simulate: vblank timer overrun