rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=b134/1/0x4000000000000000 softirq=38137/38147 fqs=5 rcu: (detected by 1, t=10502 jiffies, g=28781, q=751 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5841 Comm: syz-executor Not tainted 6.15.0-next-20250530-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:debug_spin_unlock kernel/locking/spinlock_debug.c:101 [inline] RIP: 0010:do_raw_spin_unlock+0x61/0x240 kernel/locking/spinlock_debug.c:141 Code: 4e ad de 0f 85 f3 00 00 00 48 89 df be 04 00 00 00 e8 03 08 85 00 48 89 d8 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 74 01 00 00 <83> 3b 00 0f 84 ea 00 00 00 4c 8d 73 10 4d 89 f5 49 c1 ed 03 43 80 RSP: 0018:ffffc90000007c48 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffffffff99d05f48 RCX: ffffffff819edd4d RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff99d05f48 RBP: ffffc90000007d08 R08: ffffffff99d05f4b R09: 1ffffffff33a0be9 R10: dffffc0000000000 R11: fffffbfff33a0bea R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffffff99d05f4c R15: 1ffff92000000f90 FS: 000055556d0d4500(0000) GS:ffff888125c53000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fff6f855ba8 CR3: 0000000033cc0000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:150 [inline] _raw_spin_unlock_irqrestore+0x78/0x110 kernel/locking/spinlock.c:194 debug_hrtimer_deactivate kernel/time/hrtimer.c:450 [inline] debug_deactivate+0x1d/0x200 kernel/time/hrtimer.c:490 __run_hrtimer kernel/time/hrtimer.c:1729 [inline] __hrtimer_run_queues+0x2b0/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xa8/0x110 kernel/locking/spinlock.c:194 Code: 74 05 e8 4b 7f 5f f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 73 6a 28 f6 65 8b 05 5c 63 34 07 85 c0 74 40 48 c7 04 24 0e 36 RSP: 0018:ffffc900044579c0 EFLAGS: 00000206 RAX: 089e3b75bf3fe500 RBX: 0000000000000a02 RCX: 089e3b75bf3fe500 RDX: 0000000000000006 RSI: ffffffff8d98278e RDI: 0000000000000001 RBP: ffffc90004457a50 R08: ffffffff8fa127f7 R09: 1ffffffff1f424fe R10: dffffc0000000000 R11: fffffbfff1f424ff R12: dffffc0000000000 R13: ffff888078f24118 R14: ffffffff99c6acf8 R15: 1ffff9200088af38 debug_object_activate+0x2e2/0x420 lib/debugobjects.c:836 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline] __call_rcu_common kernel/rcu/tree.c:3075 [inline] call_rcu+0x95/0x990 kernel/rcu/tree.c:3210 __destroy_inode+0x2da/0x670 fs/inode.c:371 destroy_inode fs/inode.c:394 [inline] evict+0x797/0x9c0 fs/inode.c:834 d_delete_notify include/linux/fsnotify.h:402 [inline] vfs_rmdir+0x3ec/0x520 fs/namei.c:4474 do_rmdir+0x2ac/0x630 fs/namei.c:4516 __do_sys_unlinkat fs/namei.c:4690 [inline] __se_sys_unlinkat fs/namei.c:4684 [inline] __x64_sys_unlinkat+0xc2/0xf0 fs/namei.c:4684 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fab7278df47 Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 07 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff6f856358 EFLAGS: 00000207 ORIG_RAX: 0000000000000107 RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 00007fab7278df47 RDX: 0000000000000200 RSI: 00007fff6f8574a0 RDI: 00000000ffffff9c RBP: 00007fab7281089d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000207 R12: 00007fff6f8574a0 R13: 00007fab7281089d R14: 000000000003604c R15: 00007fff6f8574e0 rcu: rcu_preempt kthread starved for 10492 jiffies! g28781 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:27192 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0x165/0x360 kernel/sched/core.c:6878 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 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: 5840 Comm: syz-executor Not tainted 6.15.0-next-20250530-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0xf69/0x12d0 kernel/smp.c:885 Code: 00 45 8b 2f 44 89 ee 83 e6 01 31 ff e8 60 78 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 0b 74 0b 00 eb 37 f3 90 <43> 0f b6 04 2c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 f0 73 0b RSP: 0018:ffffc900043b7560 EFLAGS: 00000293 RAX: ffffffff81b4ebc0 RBX: ffff8880b873cb40 RCX: ffff88802a241e00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900043b76c0 R08: ffffffff8fa127f7 R09: 1ffffffff1f424fe R10: dffffc0000000000 R11: fffffbfff1f424ff R12: 1ffff110170c86b5 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b86435a8 FS: 000055556e4fd500(0000) GS:ffff888125d53000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2b1fb7e000 CR3: 000000007c7a0000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x6b1/0x12c0 arch/x86/mm/tlb.c:1451 dup_mmap+0x15a0/0x1ac0 mm/mmap.c:1877 dup_mm kernel/fork.c:1477 [inline] copy_mm+0x13c/0x4b0 kernel/fork.c:1529 copy_process+0x1706/0x3c00 kernel/fork.c:2169 kernel_clone+0x21e/0x870 kernel/fork.c:2599 __do_sys_clone kernel/fork.c:2742 [inline] __se_sys_clone kernel/fork.c:2726 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2726 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f817d3851d3 Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 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 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffc935ef0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f817d3851d3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 000055556e4fd7d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 0000000000035fbf R15: 00007ffc935ef260