rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P16298/1:b..l rcu: (detected by 1, t=10503 jiffies, g=75609, q=219 ncpus=2) task:syz.3.3071 state:R running task stack:26392 pid:16298 tgid:16293 ppid:5815 task_flags:0x400040 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7090 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5870 Code: a0 0b 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 f2 d6 ec 0e 0f 82 74 02 00 00 8b 35 8a 06 ed 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 c9 9f 0b 12 0f 85 c7 02 00 00 48 83 c4 RSP: 0018:ffffc90003c9ec20 EFLAGS: 00000206 RAX: 0000000000000046 RBX: ffffffff8e3bf5c0 RCX: 0000000096984cfb RDX: 0000000000000000 RSI: ffffffff8dbb963f RDI: ffffffff8bf47720 RBP: 0000000000000002 R08: cdb2f65bb9cae6f2 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479 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+0x181/0x1b0 mm/page_alloc.c:1718 prep_new_page mm/page_alloc.c:1726 [inline] get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3688 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4970 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301 folio_alloc_mpol_noprof+0x36/0x2f0 mm/mempolicy.c:2320 vma_alloc_folio_noprof+0xed/0x1e0 mm/mempolicy.c:2355 folio_prealloc mm/memory.c:1054 [inline] wp_page_copy mm/memory.c:3478 [inline] do_wp_page+0x1282/0x58e0 mm/memory.c:3939 handle_pte_fault mm/memory.c:6013 [inline] __handle_mm_fault+0x1ada/0x2a40 mm/memory.c:6140 handle_mm_fault+0x3fe/0xad0 mm/memory.c:6309 do_user_addr_fault+0x7a6/0x1370 arch/x86/mm/fault.c:1388 handle_page_fault arch/x86/mm/fault.c:1480 [inline] exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1538 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 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 c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90003c9f9f8 EFLAGS: 00050246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00002000001e9030 RDX: 0000000000080000 RSI: ffffffff893d1b13 RDI: 0000000000000005 RBP: ffffc90003c9fd98 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000000 R13: 00002000001e9000 R14: ffffc90003c9fddc R15: 0000000000000002 ____sys_recvmsg+0x2ee/0x6b0 net/socket.c:2799 ___sys_recvmsg+0x114/0x1a0 net/socket.c:2828 do_recvmmsg+0x2fe/0x740 net/socket.c:2923 __sys_recvmmsg net/socket.c:2997 [inline] __do_sys_recvmmsg net/socket.c:3020 [inline] __se_sys_recvmmsg net/socket.c:3013 [inline] __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3013 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f52d798e969 RSP: 002b:00007f52d8874038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f52d7bb6080 RCX: 00007f52d798e969 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000007 RBP: 00007f52d7a10ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f52d7bb6080 R15: 00007ffce41dc7f8 rcu: rcu_preempt kthread starved for 5192 jiffies! g75609 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:27704 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2046 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2248 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 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 6.15.0-rc3-syzkaller-00094-g02ddfb981de8 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:81 Code: c5 62 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 b3 ea 1d 00 fb f4 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff8e007e10 EFLAGS: 000002c6 RAX: 0000000002e44be9 RBX: 0000000000000000 RCX: ffffffff8b6c0419 RDX: 0000000000000000 RSI: ffffffff8dbdebe6 RDI: ffffffff8bf47720 RBP: fffffbfff1c12ee8 R08: 0000000000000001 R09: ffffed10170865bd R10: ffff8880b8432deb R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff8e097740 R14: ffffffff9084e710 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881249e5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fff324c23a8 CR3: 0000000074e44000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:748 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x391/0x510 kernel/sched/idle.c:325 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:423 rest_init+0x16b/0x2b0 init/main.c:743 start_kernel+0x3e9/0x4d0 init/main.c:1099 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:513 x86_64_start_kernel+0xb0/0xc0 arch/x86/kernel/head64.c:494 common_startup_64+0x13e/0x148 IPVS: dh: UDP 224.0.0.2:0 - no destination available IPVS: dh: UDP 224.0.0.2:0 - no destination available IPVS: dh: UDP 224.0.0.2:0 - no destination available IPVS: dh: UDP 224.0.0.2:0 - no destination available IPVS: dh: UDP 224.0.0.2:0 - no destination available IPVS: dh: UDP 224.0.0.2:0 - no destination available IPVS: dh: UDP 224.0.0.2:0 - no destination available IPVS: dh: UDP 224.0.0.2:0 - no destination available