rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=675c/1/0x4000000000000000 softirq=43925/43925 fqs=5 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8910/1:b..l rcu: (detected by 0, t=10502 jiffies, g=43569, q=705 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 36 Comm: kworker/u8:2 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:lock_is_held_type+0xa/0x140 kernel/locking/lockdep.c:5934 Code: c6 96 c6 17 8e 67 48 0f b9 3a eb c7 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 8b 0d 7a f4 69 05 ff ff ff ff 85 c9 0f 84 ed 00 00 00 65 8b 15 d2 05 ab 08 85 d2 RSP: 0018:ffffc90000a08de0 EFLAGS: 00000046 RAX: ffff88807a250300 RBX: ffff88807a250300 RCX: 0000000000000001 RDX: ffff8880216d0000 RSI: 00000000ffffffff RDI: ffff88807a2502c0 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff88807a250300 R13: ffffffff89c68750 R14: ffff8880b8528640 R15: ffff8880b8528690 FS: 0000000000000000(0000) GS:ffff888123eee000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0541857d58 CR3: 000000005c640000 CR4: 00000000003526f0 DR0: 0000000000000009 DR1: 0000000000000000 DR2: 0000000000001000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: lock_is_held include/linux/lockdep.h:249 [inline] advance_sched+0x838/0xd20 net/sched/sch_taprio.c:933 __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:crng_make_state+0x2ab/0x6c0 drivers/char/random.c:383 Code: fc 4d 85 ed 0f 85 e2 01 00 00 e8 e0 6a 63 fc 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 6e 65 63 fc 48 85 db 0f 85 6c 02 00 00 c0 6a 63 fc 48 83 c4 20 5b 5d 41 5c 41 5d 41 5e 41 5f c3 cc cc RSP: 0018:ffffc90000ac79f8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff85a66739 RDX: ffff8880216d0000 RSI: ffffffff85a66747 RDI: ffff8880216d0000 RBP: ffff8880b85371f0 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 05bf1c5e694ac1df R12: 0000000000000001 R13: 0000000000000200 R14: 0000000000000006 R15: 0000000000000011 _get_random_bytes+0x11c/0x220 drivers/char/random.c:396 eth_random_addr include/linux/etherdevice.h:239 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:826 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline] nsim_dev_trap_report_work+0x370/0xd20 drivers/net/netdevsim/dev.c:922 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486 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 task:syz.4.1100 state:R running task stack:23304 pid:8910 tgid:8910 ppid:5609 task_flags:0x40064c flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0xa00 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:unwind_next_frame+0x144b/0x2090 arch/x86/kernel/unwind_orc.c:532 Code: 12 00 0f 85 23 ef ff ff 4c 89 ef c6 05 9d 7b b1 12 01 e8 e8 e8 ff ff e9 0f ef ff ff 48 b8 00 00 00 00 00 fc ff df 48 8b 14 24 <48> c1 ea 03 80 3c 02 00 0f 85 a6 08 00 00 48 89 c8 4d 8b 7d 38 48 RSP: 0018:ffffc90006b5ef30 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffffff91d406aa RDX: ffffc90006b5efd8 RSI: 0000000000000001 RDI: ffffffff9145b460 RBP: ffffc90006b5efe8 R08: ffffffff91d406ae R09: 0000000000000007 R10: 0000000000000200 R11: 00000000000184f4 R12: ffffc90006b5eff0 R13: ffffc90006b5efa0 R14: 0000000000000003 R15: 0000000000000000 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x162/0x1e0 mm/page_owner.c:165 __reset_page_owner+0x84/0x190 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] free_unref_folios+0xa44/0x1710 mm/page_alloc.c:3011 folios_put_refs+0x585/0xaa0 mm/swap.c:1057 folio_batch_release include/linux/folio_batch.h:101 [inline] shmem_undo_range+0x5e5/0x1570 mm/shmem.c:1149 shmem_truncate_range mm/shmem.c:1277 [inline] shmem_evict_inode+0x3a5/0xbe0 mm/shmem.c:1407 evict+0x3c2/0xad0 fs/inode.c:825 iput_final fs/inode.c:2019 [inline] iput.part.0+0x989/0x1050 fs/inode.c:2068 iput+0x35/0x40 fs/inode.c:2034 dentry_unlink_inode+0x284/0x470 fs/dcache.c:479 dentry_kill+0x25d/0xc20 fs/dcache.c:826 finish_dput fs/dcache.c:1001 [inline] dput.part.0+0xd7/0x240 fs/dcache.c:1042 dput+0x1f/0x30 fs/dcache.c:1037 __fput+0x519/0xb50 fs/file_table.c:520 task_work_run+0x150/0x240 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x951/0x2ae0 kernel/exit.c:1004 do_group_exit+0xd5/0x2a0 kernel/exit.c:1147 get_signal+0x1ec7/0x21e0 kernel/signal.c:3038 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop kernel/entry/common.c:101 [inline] __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline] irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline] irqentry_exit+0x402/0xa00 kernel/entry/common.c:165 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595 RIP: 0033:0x7fe53719de61 RSP: 002b:fffffffffffffe70 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007fe537425fa0 RCX: 00007fe53719de59 RDX: 0000000000000000 RSI: fffffffffffffe70 RDI: 0000000000008000 RBP: 00007fe537233e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007fe537426038 R14: 00007fe537425fa0 R15: 00007ffc4b9063e8 rcu: rcu_preempt kthread starved for 10492 jiffies! g43569 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:26712 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: CPU: 0 UID: 0 PID: 8483 Comm: syz-executor Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026 RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x17/0x70 kernel/kcov.c:217 Code: 03 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 65 8b 05 05 50 59 12 48 8b 34 24 65 48 8b 15 e1 4f 59 12 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 e9 11 d1 RSP: 0018:ffffc900192e7610 EFLAGS: 00000202 RAX: 0000000000000002 RBX: 0000000000000001 RCX: ffffffff81fd3a8d RDX: ffff88807c038000 RSI: ffffffff81fd3a67 RDI: ffff88807c038000 RBP: ffff8880b8541240 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170a8249 R14: 0000000000000001 R15: ffff8880b843c880 FS: 000055558073f500(0000) GS:ffff888123dee000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30a1dff8 CR3: 000000007a3be000 CR4: 00000000003526f0 DR0: 0000000000000009 DR1: 0000000000000000 DR2: 0000000000001000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: native_pause arch/x86/include/asm/vdso/processor.h:13 [inline] cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline] csd_lock_wait kernel/smp.c:342 [inline] smp_call_function_many_cond+0x587/0x16c0 kernel/smp.c:892 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057 __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x45f/0x16f0 arch/x86/mm/tlb.c:1451 dup_mmap+0x1307/0x21b0 mm/mmap.c:1905 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: 0033:0x7f6b04fc68d2 Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffe25b4eec0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffe25b4eec0 RCX: 00007f6b04fc68d2 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffe25b4f04c R08: 0000000000000000 R09: 0000000000000001 R10: 000055558073f7d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 000000000003580b R15: 00007ffe25b4f0a0