rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P20984/1:b..l rcu: (detected by 0, t=10523 jiffies, g=121149, q=232 ncpus=2) task:modprobe state:R running task stack:24872 pid:20984 tgid:20984 ppid:16854 task_flags:0x400000 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 preempt_schedule_notrace+0x5f/0xd0 kernel/sched/core.c:7506 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x8e/0xc0 kernel/rcu/tree.c:753 rcu_read_lock_held_common kernel/rcu/update.c:109 [inline] rcu_read_lock_held+0x1e/0x50 kernel/rcu/update.c:349 __d_lookup_rcu+0x2f5/0x500 fs/dcache.c:2497 lookup_fast+0x90/0x600 fs/namei.c:1854 walk_component fs/namei.c:2278 [inline] link_path_walk+0x7d4/0x1cc0 fs/namei.c:2656 path_openat+0x1c9/0x4280 fs/namei.c:4855 do_file_open+0x20e/0x430 fs/namei.c:4888 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368 do_sys_open fs/open.c:1374 [inline] __do_sys_openat fs/open.c:1390 [inline] __se_sys_openat fs/open.c:1385 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1385 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdf78bd70ba RSP: 002b:00007fff7552b408 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fff7552b480 RCX: 00007fdf78bd70ba RDX: 0000000000080000 RSI: 00007fff7552b480 RDI: 00000000ffffff9c RBP: 00007fff7552b470 R08: 00007fff7552b677 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 000000000000001b R13: 00007fdf78bab050 R14: 00007fff7552b690 R15: 0000000000000000 rcu: rcu_preempt kthread timer wakeup didn't happen for 10522 jiffies! g121149 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=60607 rcu: rcu_preempt kthread starved for 10523 jiffies! g121149 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:28680 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7326 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 20970 Comm: syz.4.3410 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:__netif_schedule+0x54/0x70 net/core/dev.c:3406 Code: 2f 48 8b 83 08 02 00 00 48 85 c0 74 0b e8 94 e1 9a f8 5b e9 ce 72 31 02 e8 89 e1 9a f8 48 89 df e8 b1 fc ff ff e8 7c e1 9a f8 <5b> c3 cc cc cc cc e8 91 54 0b f9 eb ca 66 66 2e 0f 1f 84 00 00 00 RSP: 0000:ffffc90000a08dd8 EFLAGS: 00000046 RAX: 0000000080010003 RBX: ffff8880316ac000 RCX: ffffffff896e9b86 RDX: ffff88802880a540 RSI: ffffffff896e9ea4 RDI: ffff88802880a540 RBP: ffff888054852000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 18bd6cbeeb85999f R14: ffff88803c8fb800 R15: ffff88803c8fb800 FS: 00007f1c1719e6c0(0000) GS:ffff8881241e0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555720664e8 CR3: 000000003e195000 CR4: 00000000003526f0 Call Trace: advance_sched+0x740/0xd20 net/sched/sch_taprio.c:993 __run_hrtimer kernel/time/hrtimer.c:2032 [inline] __hrtimer_run_queues+0x462/0x9c0 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872 Code: 05 bb ef 4e 12 83 f8 07 0f 87 da 00 00 00 48 0f a3 05 06 a2 16 0f 0f 82 ac 02 00 00 8b 35 ce d5 16 0f 85 f6 0f 85 c7 00 00 00 <48> 8b 44 24 30 65 48 2b 05 5d ef 4e 12 0f 85 ec 02 00 00 48 83 c4 RSP: 0000:ffffc90004ab73d8 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8e137c0e RDI: ffffffff8c3e9b80 RBP: ffffffff8e9e6000 R08: 000000002c4e968d R09: 000000000000001e R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock_sched include/linux/rcupdate.h:938 [inline] pfn_valid include/linux/mmzone.h:2270 [inline] page_table_check_set+0x6b/0x920 mm/page_table_check.c:105 __page_table_check_ptes_set+0x27a/0x4e0 mm/page_table_check.c:212 page_table_check_ptes_set include/linux/page_table_check.h:83 [inline] set_ptes include/linux/pgtable.h:447 [inline] __copy_present_ptes mm/memory.c:1118 [inline] copy_present_ptes mm/memory.c:1197 [inline] copy_pte_range mm/memory.c:1320 [inline] copy_pmd_range mm/memory.c:1408 [inline] copy_pud_range mm/memory.c:1445 [inline] copy_p4d_range mm/memory.c:1469 [inline] copy_page_range+0x2197/0x5b20 mm/memory.c:1555 dup_mmap+0xd44/0x21b0 mm/mmap.c:1840 dup_mm kernel/fork.c:1538 [inline] copy_mm kernel/fork.c:1590 [inline] copy_process+0x4588/0x8030 kernel/fork.c:2288 kernel_clone+0x176/0x9d0 kernel/fork.c:2747 __do_sys_clone+0xd9/0x120 kernel/fork.c:2888 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1c1639ce59 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:00007f1c1719dfd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007f1c16616180 RCX: 00007f1c1639ce59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f1c16432e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1c16616218 R14: 00007f1c16616180 R15: 00007ffebc3f5c98