rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P25214/1:b..l rcu: (detected by 0, t=10502 jiffies, g=120521, q=461 ncpus=2) task:syz.3.5073 state:R running task stack:26344 pid:25214 tgid:25210 ppid:17349 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0xfe4/0x5e10 kernel/sched/core.c:6867 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7194 irqentry_exit+0x17b/0x670 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_release+0x20/0x2e0 kernel/locking/lockdep.c:5876 Code: 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 54 55 53 48 89 fb 48 83 ec 18 65 48 8b 2d 3d 4d 01 12 48 89 6c 24 10 <48> 89 f5 0f 1f 44 00 00 65 8b 05 55 4d 01 12 83 f8 07 0f 87 3c 02 RSP: 0018:ffffc90005146ec8 EFLAGS: 00000292 RAX: 0000000000080000 RBX: ffffffff8e5e32e0 RCX: ffffc9000cdba000 RDX: 0000000000080000 RSI: ffffffff827c65e2 RDI: ffffffff8e5e32e0 RBP: d9ae76d45b87ea00 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 00000000000050dc R13: dffffc0000000000 R14: 0000000000000001 R15: 0000000000000001 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] __update_page_owner_handle+0x3c7/0x550 mm/page_owner.c:270 __set_page_owner+0x11f/0x540 mm/page_owner.c:342 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1e1/0x250 mm/page_alloc.c:1884 prep_new_page mm/page_alloc.c:1892 [inline] get_page_from_freelist+0xe3d/0x2e10 mm/page_alloc.c:3945 __alloc_frozen_pages_noprof+0x26c/0x2410 mm/page_alloc.c:5240 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2486 folio_alloc_mpol_noprof+0x36/0x340 mm/mempolicy.c:2505 shmem_alloc_folio+0x135/0x160 mm/shmem.c:1913 shmem_alloc_and_add_folio+0x371/0xd40 mm/shmem.c:1955 shmem_get_folio_gfp+0x6ab/0x1900 mm/shmem.c:2579 shmem_fault+0x1f9/0xa20 mm/shmem.c:2780 __do_fault+0x10d/0x550 mm/memory.c:5323 do_read_fault mm/memory.c:5758 [inline] do_fault+0xaf9/0x1990 mm/memory.c:5892 do_pte_missing mm/memory.c:4404 [inline] handle_pte_fault mm/memory.c:6276 [inline] __handle_mm_fault+0x1807/0x2b50 mm/memory.c:6414 handle_mm_fault+0x36d/0xa20 mm/memory.c:6583 faultin_page mm/gup.c:1126 [inline] __get_user_pages+0xf9c/0x34d0 mm/gup.c:1428 populate_vma_page_range+0x267/0x3f0 mm/gup.c:1860 __mm_populate+0x107/0x3a0 mm/gup.c:1963 mm_populate include/linux/mm.h:3705 [inline] vm_mmap_pgoff+0x37f/0x470 mm/util.c:586 ksys_mmap_pgoff+0x7d/0x5b0 mm/mmap.c:604 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline] __se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline] __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f89ff19aeb9 RSP: 002b:00007f89fffbf028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f89ff416090 RCX: 00007f89ff19aeb9 RDX: 0000000000000003 RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007f89ff208c1f R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f89ff416128 R14: 00007f89ff416090 R15: 00007ffcc2e38808 rcu: rcu_preempt kthread starved for 10076 jiffies! g120521 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:28168 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0xfe4/0x5e10 kernel/sched/core.c:6867 __schedule_loop kernel/sched/core.c:6949 [inline] schedule+0xdd/0x390 kernel/sched/core.c:6964 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0xb00 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x21e/0x320 kernel/rcu/tree.c:2285 kthread+0x3b3/0x730 kernel/kthread.c:463 ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: 56 78 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 03 ae 14 00 fb f4 fc 31 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff8e207e00 EFLAGS: 00000246 RAX: 000000000435f44b RBX: ffffffff8e297ac0 RCX: ffffffff8b76d4b5 RDX: 0000000000000000 RSI: ffffffff8dc45ba3 RDI: ffffffff8bfa3620 RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed101708673d R10: ffff8880b84339eb R11: 0000000000000000 R12: fffffbfff1c52f58 R13: 0000000000000000 R14: ffffffff90b749d0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881245d9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c28ccff CR3: 0000000028003000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x9/0x10 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x35b/0x4b0 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 rest_init+0x251/0x260 init/main.c:757 start_kernel+0x47a/0x480 init/main.c:1206 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x122/0x130 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x148