rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P15425/1:b..l rcu: (detected by 0, t=10502 jiffies, g=75101, q=731 ncpus=2) task:modprobe state:R running task stack:24488 pid:15425 tgid:15425 ppid:6367 task_flags:0x400000 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5263 [inline] __schedule+0x1836/0x4ed0 kernel/sched/core.c:6871 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7198 irqentry_exit+0x5b5/0x640 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x16c/0x350 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 14 ff d7 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc9001a4ef7d8 EFLAGS: 00000206 RAX: e5f7cadb7c560b00 RBX: 0000000000000000 RCX: e5f7cadb7c560b00 RDX: 0000000000000001 RSI: ffffffff8d9761d1 RDI: ffffffff8bbf80e0 RBP: ffffffff81741ff5 R08: 0000000000000000 R09: ffffffff81741ff5 R10: ffffc9001a4ef998 R11: ffffffff81ada5d0 R12: 0000000000000002 R13: ffffffff8df3d9c0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 unpoison_slab_object mm/kasan/common.c:339 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:365 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4948 [inline] slab_alloc_node mm/slub.c:5258 [inline] kmem_cache_alloc_noprof+0x37d/0x700 mm/slub.c:5265 getname_flags+0xb8/0x540 fs/namei.c:146 getname include/linux/fs.h:2499 [inline] do_sys_openat2+0xbc/0x1c0 fs/open.c:1426 do_sys_open fs/open.c:1447 [inline] __do_sys_openat fs/open.c:1463 [inline] __se_sys_openat fs/open.c:1458 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1458 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb2d9eb80ba RSP: 002b:00007fff8ee0c5b8 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fff8ee0c630 RCX: 00007fb2d9eb80ba RDX: 0000000000080000 RSI: 00007fff8ee0c630 RDI: 00000000ffffff9c RBP: 00007fff8ee0c620 R08: 00007fff8ee0c827 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000018 R13: 00007fb2d9e8c000 R14: 00007fff8ee0c840 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10356 jiffies! g75101 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:26776 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5263 [inline] __schedule+0x1836/0x4ed0 kernel/sched/core.c:6871 __schedule_loop kernel/sched/core.c:6953 [inline] schedule+0x165/0x360 kernel/sched/core.c:6968 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 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 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: cc cc cc cc 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 33 00 0d 00 f3 0f 1e fa fb f4 48 f1 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8dc07d80 EFLAGS: 000002c6 RAX: 417cb11c29928700 RBX: ffffffff81978747 RCX: 417cb11c29928700 RDX: 0000000000000001 RSI: ffffffff8d78f926 RDI: ffffffff8bbf80e0 RBP: ffffffff8dc07ea8 R08: ffff8880b86336db R09: 1ffff110170c66db R10: dffffc0000000000 R11: ffffed10170c66dc R12: ffffffff8f7deb70 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1b92a60 FS: 0000000000000000(0000) GS:ffff888125eb9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff74f55ee80 CR3: 000000007e588000 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+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x1e7/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 rest_init+0x2de/0x300 init/main.c:757 start_kernel+0x3a7/0x410 init/main.c:1206 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147