rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5818/1:b..l P10964/1:b..l rcu: (detected by 0, t=10502 jiffies, g=37793, q=60 ncpus=2) task:syz-executor state:R running task stack:28312 pid:10964 tgid:10964 ppid:5821 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_notrace+0x62/0xe0 kernel/sched/core.c:7140 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x8e/0xc0 kernel/rcu/tree.c:752 rcu_read_unlock include/linux/rcupdate.h:895 [inline] class_rcu_destructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xa3b/0x20b0 arch/x86/kernel/unwind_orc.c:495 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:165 __set_page_owner+0x91/0x560 mm/page_owner.c:341 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1af/0x220 mm/page_alloc.c:1857 prep_new_page mm/page_alloc.c:1865 [inline] get_page_from_freelist+0xd0b/0x31a0 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x25f/0x2430 mm/page_alloc.c:5210 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2486 folio_alloc_mpol_noprof+0x36/0x2f0 mm/mempolicy.c:2505 vma_alloc_folio_noprof+0xed/0x1e0 mm/mempolicy.c:2540 folio_prealloc mm/memory.c:1193 [inline] wp_page_copy mm/memory.c:3719 [inline] do_wp_page+0x202f/0x5010 mm/memory.c:4180 handle_pte_fault mm/memory.c:6289 [inline] __handle_mm_fault+0x1bd2/0x2bb0 mm/memory.c:6411 handle_mm_fault+0x3fe/0xad0 mm/memory.c:6580 do_user_addr_fault+0x60c/0x1370 arch/x86/mm/fault.c:1336 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: 0033:0x7f05452649a2 RSP: 002b:00007ffd91f25630 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 00007f054541566e RSI: 0000000000000040 RDI: 00007ffd91f25780 RBP: 00007ffd91f25780 R08: 0000000000000557 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000102 R13: 00000000000927c0 R14: 0000000000068258 R15: 00007ffd91f258e0 task:syz-executor state:R running task stack:23736 pid:5818 tgid:5818 ppid:5809 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_release+0x183/0x2d0 kernel/locking/lockdep.c:5893 Code: 0f c1 05 f8 00 19 12 83 f8 01 0f 85 03 01 00 00 9c 58 f6 c4 02 0f 85 ee 00 00 00 41 f7 c5 00 02 00 00 74 01 fb 48 8b 44 24 10 <65> 48 2b 05 8d b9 18 12 0f 85 32 01 00 00 48 83 c4 18 5b 41 5c 41 RSP: 0018:ffffc90002ea7410 EFLAGS: 00000206 RAX: 67ac7d9b5c3dee00 RBX: ffffffff8e3c96a0 RCX: ffffc90002ea741c RDX: 0000000000000003 RSI: ffffffff8daa7ee5 RDI: ffffffff8bf2b400 RBP: 0000000000000001 R08: ffffffff912fbf06 R09: 0000000009ecfde3 R10: 0000000000000002 R11: 0000000000012887 R12: ffffffff816cb9a4 R13: 0000000000000206 R14: ffff88807aae0000 R15: 0000000000000004 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] class_rcu_destructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0x3f9/0x20b0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_noprof+0x25e/0x770 mm/slub.c:5270 anon_vma_chain_alloc mm/rmap.c:141 [inline] anon_vma_clone+0xd8/0x5c0 mm/rmap.c:287 anon_vma_fork+0x7a/0x620 mm/rmap.c:350 dup_mmap+0x12d3/0x20e0 mm/mmap.c:1790 dup_mm kernel/fork.c:1529 [inline] copy_mm kernel/fork.c:1581 [inline] copy_process+0x3b9f/0x7430 kernel/fork.c:2221 kernel_clone+0xfc/0x910 kernel/fork.c:2651 __do_sys_clone+0xce/0x120 kernel/fork.c:2792 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f71fa985e93 RSP: 002b:00007ffd9f0fafa8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f71fa985e93 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 00005555888147d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 0000000000067c60 R15: 00007ffd9f0fb140 rcu: rcu_preempt kthread starved for 10523 jiffies! g37793 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:27720 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6960 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+0x983/0xb10 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 10/25/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: d6 5f 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 13 59 12 00 fb f4 cc 35 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: 0000000001cef9e7 RBX: 0000000000000000 RCX: ffffffff8b7806d9 RDX: 0000000000000000 RSI: ffffffff8dacdf79 RDI: ffffffff8bf2b400 RBP: fffffbfff1c12f68 R08: 0000000000000001 R09: ffffed101708673d R10: ffff8880b84339eb R11: ffffffff8e098670 R12: 0000000000000000 R13: ffffffff8e097b40 R14: ffffffff9088b6d0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881248f5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1eec5440e8 CR3: 0000000075f25000 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:191 [inline] do_idle+0x38d/0x510 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 rest_init+0x16b/0x2b0 init/main.c:757 start_kernel+0x3ef/0x4d0 init/main.c:1206 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