rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10254/1:b..l rcu: (detected by 1, t=10506 jiffies, g=33533, q=432 ncpus=2) task:sed state:R running task stack:22184 pid:10254 tgid:10254 ppid:10251 task_flags:0x400000 flags:0x00080801 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7190 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x16c/0x340 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 d4 38 e0 10 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc900033d6c18 EFLAGS: 00000206 RAX: 52e4629659f34a00 RBX: 0000000000000000 RCX: 52e4629659f34a00 RDX: 00000000b5c0162b RSI: ffffffff8d979277 RDI: ffffffff8bc08360 RBP: ffffffff81743f85 R08: ffffffff81743f85 R09: ffffffff8df41a20 R10: ffffc900033d6dd8 R11: ffffffff81ada120 R12: 0000000000000002 R13: ffffffff8df41a20 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+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:165 __set_page_owner+0x8d/0x4c0 mm/page_owner.c:341 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x234/0x290 mm/page_alloc.c:1846 prep_new_page mm/page_alloc.c:1854 [inline] get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486 alloc_frozen_pages_noprof mm/mempolicy.c:2557 [inline] alloc_pages_noprof+0xa9/0x190 mm/mempolicy.c:2577 pagetable_alloc_noprof include/linux/mm.h:3190 [inline] __pte_alloc_one_noprof include/asm-generic/pgalloc.h:76 [inline] pte_alloc_one+0x23/0x370 arch/x86/mm/pgtable.c:18 __do_fault+0xd1/0x390 mm/memory.c:5315 do_cow_fault mm/memory.c:5785 [inline] do_fault mm/memory.c:5891 [inline] do_pte_missing+0x554/0x3330 mm/memory.c:4401 handle_pte_fault mm/memory.c:6273 [inline] __handle_mm_fault mm/memory.c:6411 [inline] handle_mm_fault+0x1b26/0x32b0 mm/memory.c:6580 do_user_addr_fault+0x764/0x1380 arch/x86/mm/fault.c:1387 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0010:rep_stos_alternative+0x40/0x80 arch/x86/lib/clear_page_64.S:99 Code: c9 75 f6 e9 92 59 04 00 48 89 07 48 83 c7 08 83 e9 08 74 ef 83 f9 08 73 ef eb de 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 <48> 89 07 48 89 47 08 48 89 47 10 48 89 47 18 48 89 47 20 48 89 47 RSP: 0018:ffffc900033d7a48 EFLAGS: 00050206 RAX: 0000000000000000 RBX: 0000560b09fac010 RCX: 0000000000000ff8 RDX: 0000000000000000 RSI: ffffffff8d979277 RDI: 0000560b09fac008 RBP: dffffc0000000000 R08: ffffffff820f72d0 R09: ffff8880271fe540 R10: dffffc0000000000 R11: ffffed10063e33d1 R12: 0000560b09fac008 R13: 0000000000000008 R14: 0000000000000ff8 R15: ffff88804ecd7118 __clear_user arch/x86/include/asm/uaccess_64.h:188 [inline] clear_user arch/x86/include/asm/uaccess_64.h:205 [inline] padzero fs/binfmt_elf.c:133 [inline] elf_load+0x4d2/0x6c0 fs/binfmt_elf.c:435 load_elf_binary+0x1079/0x2740 fs/binfmt_elf.c:1188 search_binary_handler fs/exec.c:1669 [inline] exec_binprm fs/exec.c:1701 [inline] bprm_execve+0x92e/0x1400 fs/exec.c:1753 do_execveat_common+0x510/0x6a0 fs/exec.c:1859 do_execve fs/exec.c:1933 [inline] __do_sys_execve fs/exec.c:2009 [inline] __se_sys_execve fs/exec.c:2004 [inline] __x64_sys_execve+0x94/0xb0 fs/exec.c:2004 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fef6ccb1107 RSP: 002b:00007fff872f2b78 EFLAGS: 00000246 ORIG_RAX: 000000000000003b RAX: ffffffffffffffda RBX: 00005626748e7078 RCX: 00007fef6ccb1107 RDX: 00005626748e70a0 RSI: 00005626748e7078 RDI: 00005626748e7130 RBP: 00005626748e7130 R08: 00007fff872f8ea6 R09: 0000000000000000 R10: 0000000000000008 R11: 0000000000000246 R12: 00005626748e70a0 R13: 00007fef6ce76e8b R14: 00005626748e70a0 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 2269 jiffies! g33533 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:26152 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5197 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:bpf_prog_07d8dd54622f5a97+0x39/0x5f Code: e5 f3 0f 1e fa 48 81 ec 10 00 00 00 48 c7 45 f0 ff ff 00 00 48 c7 45 f8 00 00 00 00 48 b8 00 00 00 00 ff ff ff 80 4c 8b 55 f0 <4d> 85 d2 74 1b 49 83 ea 01 4d 85 d2 75 0c 49 c7 c2 f0 ff ff ff e8 RSP: 0018:ffffc90003107680 EFLAGS: 00000002 RAX: 80ffffff00000000 RBX: 1ffff1100f89130a RCX: ffff88807c488000 RDX: 0000000000000000 RSI: ffffc90004a18060 RDI: ffffc90003107720 RBP: ffffc90003107690 R08: ffffffff81cdd72c R09: ffffffff8df41a20 R10: 00000000000048c7 R11: ffffffff8168e910 R12: ffffc90004a18048 R13: dffffc0000000000 R14: ffff88807c489850 R15: ffffc90004a18060 FS: 00007f41fc00a880(0000) GS:ffff888125e35000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f26cede20b8 CR3: 000000007c948000 CR4: 00000000003526f0 Call Trace: bpf_dispatcher_nop_func include/linux/bpf.h:1378 [inline] __bpf_prog_run include/linux/filter.h:723 [inline] bpf_prog_run include/linux/filter.h:730 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline] bpf_trace_run4+0x28e/0x4b0 kernel/trace/bpf_trace.c:2118 __bpf_trace_sched_switch+0x17a/0x1e0 include/trace/events/sched.h:220 __traceiter_sched_switch+0x9d/0xd0 include/trace/events/sched.h:220 __do_trace_sched_switch include/trace/events/sched.h:220 [inline] trace_sched_switch include/trace/events/sched.h:220 [inline] __schedule+0x256b/0x5000 kernel/sched/core.c:6860 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7047 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7071 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0xfd/0x110 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] unlock_task_sighand include/linux/sched/signal.h:756 [inline] do_send_sig_info kernel/signal.c:1270 [inline] group_send_sig_info+0x233/0x260 kernel/signal.c:1419 kill_pid_info_type+0xf8/0x1f0 kernel/signal.c:1459 kill_pid_info kernel/signal.c:1473 [inline] kill_proc_info+0xd9/0x180 kernel/signal.c:1480 kill_something_info kernel/signal.c:1577 [inline] __do_sys_kill kernel/signal.c:3953 [inline] __se_sys_kill+0xc4/0x450 kernel/signal.c:3947 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f41fb85f357 Code: 48 83 c4 08 c3 66 0f 1f 44 00 00 48 8b 15 99 1a 19 00 64 89 02 b8 ff ff ff ff eb e4 0f 1f 80 00 00 00 00 b8 3e 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 71 1a 19 00 f7 d8 64 89 01 48 RSP: 002b:00007ffdb1598088 EFLAGS: 00000297 ORIG_RAX: 000000000000003e RAX: ffffffffffffffda RBX: 00007ffdb1598090 RCX: 00007f41fb85f357 RDX: 000055c3d0687100 RSI: 000000000000000f RDI: 000000000000184c RBP: 0000000000000000 R08: 0000000000000010 R09: 000055c3d067c8e0 R10: 0000000000000044 R11: 0000000000000297 R12: 0000000000000000 R13: 000055c3a4ce3100 R14: 0000000000000000 R15: 0000000000000000