rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=2dfc/1/0x4000000000000000 softirq=117517/117518 fqs=3 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8789/1:b..l rcu: (detected by 1, t=10505 jiffies, g=127009, q=520 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 18576 Comm: syz.2.2761 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:hlock_class kernel/locking/lockdep.c:234 [inline] RIP: 0010:check_wait_context kernel/locking/lockdep.c:4870 [inline] RIP: 0010:__lock_acquire+0x37e/0x2e50 kernel/locking/lockdep.c:5204 Code: 49 09 cc 49 09 d4 4c 8d 34 c5 00 00 00 00 4d 01 ee 4c 89 6c 24 28 4d 89 64 c5 20 41 81 e4 ff 1f 00 00 4c 0f a3 25 12 02 d4 12 <73> 10 49 69 c4 c8 00 00 00 48 8d 80 10 f5 17 94 eb 3a 83 3d d9 91 RSP: 0018:ffffc90000007b68 EFLAGS: 00000047 RAX: 0000000000000014 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000044000 RSI: 0000000000004000 RDI: ffff88803403ddc0 RBP: 0000000000000000 R08: 0300000000000000 R09: 0000000000080000 R10: 0000000000000000 R11: ffffffff9aa4b660 R12: 0000000000000000 R13: ffff88803403e970 R14: ffff88803403ea10 R15: 0000000000000004 FS: 00007f9d2cabe6c0(0000) GS:ffff888124f0c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f023c5eb7c0 CR3: 0000000057a2a000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5908 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline] _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166 debug_object_deactivate+0x9a/0x250 lib/debugobjects.c:936 debug_hrtimer_deactivate kernel/time/hrtimer.c:491 [inline] __run_hrtimer kernel/time/hrtimer.c:2034 [inline] __hrtimer_run_queues+0x239/0xa10 kernel/time/hrtimer.c:2123 hrtimer_interrupt+0x448/0x910 kernel/time/hrtimer.c:2242 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:is_bpf_text_address+0x5/0x2b0 kernel/bpf/core.c:746 Code: 00 00 31 ff 4c 89 ea e8 b9 92 53 ff 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 55 <41> 57 41 56 41 55 41 54 53 48 83 ec 10 49 89 fe e8 56 80 ef ff e8 RSP: 0018:ffffc90005f9f248 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00007f9d2bb9e0d9 RCX: 0000000000000046 RDX: 00000000ec056780 RSI: ffffffff8e4d9480 RDI: 00007f9d2bb9e0d9 RBP: 0000000000000001 R08: 4300000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8eb5c6a0 R12: ffff88803403ddc0 R13: ffffffff822a6194 R14: 0000000000000001 R15: 1ffff92000bf3e5e kernel_text_address+0xa5/0xe0 kernel/extable.c:125 __kernel_text_address+0xd/0x30 kernel/extable.c:79 unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:385 arch_stack_walk+0xfb/0x150 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] kmem_cache_alloc_noprof+0x2b5/0x600 mm/slub.c:5010 anon_vma_chain_alloc mm/rmap.c:142 [inline] anon_vma_fork+0x158/0x540 mm/rmap.c:394 dup_mmap+0x954/0x1dc0 mm/mmap.c:1781 dup_mm kernel/fork.c:1549 [inline] copy_mm+0x11a/0x480 kernel/fork.c:1601 copy_process+0x1e75/0x43e0 kernel/fork.c:2313 kernel_clone+0x2d7/0x940 kernel/fork.c:2772 __do_sys_clone kernel/fork.c:2914 [inline] __se_sys_clone kernel/fork.c:2898 [inline] __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2898 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x510 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9d2bb9e0d9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f9d2cabdfd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007f9d2be25fa0 RCX: 00007f9d2bb9e0d9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000002280600 RBP: 00007f9d2bc35024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f9d2be26038 R14: 00007f9d2be25fa0 R15: 00007fff781eedd8 task:syz-executor state:R running task stack:22160 pid:8789 tgid:8789 ppid:8779 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x1b2a/0x59a0 kernel/sched/core.c:7232 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7411 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:190 spin_unlock include/linux/spinlock.h:390 [inline] copy_pte_range mm/memory.c:1429 [inline] copy_pmd_range+0x516a/0x5c00 mm/memory.c:1490 copy_pud_range mm/memory.c:1527 [inline] copy_p4d_range mm/memory.c:1551 [inline] copy_page_range+0xc82/0x1290 mm/memory.c:1637 dup_mmap+0xf17/0x1dc0 mm/mmap.c:1819 dup_mm kernel/fork.c:1549 [inline] copy_mm+0x11a/0x480 kernel/fork.c:1601 copy_process+0x1e75/0x43e0 kernel/fork.c:2313 kernel_clone+0x2d7/0x940 kernel/fork.c:2772 __do_sys_clone kernel/fork.c:2914 [inline] __se_sys_clone kernel/fork.c:2898 [inline] __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2898 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x510 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8ecc5c6b52 RSP: 002b:00007fffa4d59c10 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007fffa4d59c10 RCX: 00007f8ecc5c6b52 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007fffa4d59d9c R08: 0000000000000000 R09: 0000000000000001 R10: 000055558ca497d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 00000000000f4ca3 R15: 00007fffa4d59df0 rcu: rcu_preempt kthread starved for 10490 jiffies! g127009 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->cpu=1 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:27496 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x1b2a/0x59a0 kernel/sched/core.c:7232 __schedule_loop kernel/sched/core.c:7309 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7324 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64 Code: 0c 77 02 e9 03 07 03 00 cc cc cc 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 e3 4e 0e 00 fb f4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffc900001a7e40 EFLAGS: 00000246 RAX: 0000000000d2642d RBX: ffffffff819b739c RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8e253559 RDI: ffffffff8c4c7680 RBP: ffffc900001a7f10 R08: ffff8880b8733b9b R09: 1ffff110170e6773 R10: dffffc0000000000 R11: ffffed10170e6774 R12: 0000000000000000 R13: 1ffff11003c5cbb8 R14: 1ffff92000034fd0 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff88812500c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb4c0587240 CR3: 0000000077112000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: arch_safe_halt arch/x86/kernel/process.c:767 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:768 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x1cc/0x540 kernel/sched/idle.c:355 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:454 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x157