rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=92bc/1/0x4000000000000000 softirq=52181/52181 fqs=1 rcu: (detected by 0, t=10502 jiffies, g=39829, q=218 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 10597 Comm: syz.3.1340 Not tainted 6.16.0-rc2-next-20250618-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:check_preemption_disabled+0x3/0x120 lib/smp_processor_id.c:13 Code: e2 8b 48 c7 c6 c0 f5 e2 8b eb 1c 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 <41> 56 53 48 83 ec 10 65 48 8b 05 de 2d 34 07 48 89 44 24 08 65 8b RSP: 0018:ffffc90000a08c10 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000001 RCX: 6def26b4ac01fa00 RDX: ffff88802541da00 RSI: ffffffff8db7aaf9 RDI: ffffffff8be2f5e0 RBP: 00000000ffffffff R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff5200014117c R12: 0000000000000046 R13: ffff88802541da00 R14: ffff8880779b4300 R15: 0000000000000005 FS: 00007f23d33b66c0(0000) GS:ffff888125d3d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f23d3395d58 CR3: 000000007920e000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:473 [inline] lock_is_held_type+0xfe/0x190 kernel/locking/lockdep.c:5944 lock_is_held include/linux/lockdep.h:249 [inline] advance_sched+0xe7/0xc90 net/sched/sch_taprio.c:925 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x529/0xc60 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+0x10b/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:seqcount_lockdep_reader_access+0x17d/0x1c0 include/linux/seqlock.h:75 Code: ff 4d 85 ed 75 16 e8 22 2c 85 ff eb 15 e8 1b 2c 85 ff e8 06 be 2e 09 4d 85 ed 74 ea e8 0c 2c 85 ff fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 27 00 00 00 00 66 43 c7 44 27 09 00 00 43 c6 44 27 0b 00 RSP: 0018:ffffc9000e65fa20 EFLAGS: 00000283 RAX: ffffffff823b2b34 RBX: 0000000000000000 RCX: 0000000000080000 RDX: ffffc9000c3bb000 RSI: 00000000000031c3 RDI: 00000000000031c4 RBP: ffffc9000e65fae0 R08: ffffffff8fa16cf7 R09: 1ffffffff1f42d9e R10: dffffc0000000000 R11: fffffbfff1f42d9f R12: dffffc0000000000 R13: 0000000000000200 R14: ffffffff823b2607 R15: 1ffff92001ccbf44 take_dentry_name_snapshot+0x157/0x500 fs/dcache.c:367 vfs_rename+0x619/0xf00 fs/namei.c:5073 do_renameat2+0x6ce/0xa80 fs/namei.c:5278 __do_sys_rename fs/namei.c:5325 [inline] __se_sys_rename fs/namei.c:5323 [inline] __x64_sys_rename+0x82/0x90 fs/namei.c:5323 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: 0033:0x7f23d258e929 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f23d33b6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000052 RAX: ffffffffffffffda RBX: 00007f23d27b5fa0 RCX: 00007f23d258e929 RDX: 0000000000000000 RSI: 00002000000000c0 RDI: 0000200000000000 RBP: 00007f23d2610b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f23d27b5fa0 R15: 00007ffe8405ac58 rcu: rcu_preempt kthread starved for 10495 jiffies! g39829 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:27128 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5313 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6696 __schedule_loop kernel/sched/core.c:6774 [inline] schedule+0x165/0x360 kernel/sched/core.c:6789 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2060 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2262 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3f9/0x770 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: 0 UID: 0 PID: 198 Comm: kworker/u8:5 Not tainted 6.16.0-rc2-next-20250618-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:check_kcov_mode kernel/kcov.c:194 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x37/0x70 kernel/kcov.c:217 Code: 08 30 9e 92 65 8b 15 d8 d8 dd 10 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 3c 16 00 00 00 74 2c 8b 91 18 16 00 00 <83> fa 02 75 21 48 8b 91 20 16 00 00 48 8b 32 48 8d 7e 01 8b 89 1c RSP: 0018:ffffc90002fa7698 EFLAGS: 00000246 RAX: ffffffff81b4f210 RBX: ffff8880b863b180 RCX: ffff888020bbda00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90002fa7800 R08: ffffffff8fa16cf7 R09: 1ffffffff1f42d9e R10: dffffc0000000000 R11: fffffbfff1f42d9f R12: 1ffff110170e7f59 R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8880b873fac8 FS: 0000000000000000(0000) GS:ffff888125c3d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33d1eff8 CR3: 000000000df38000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: csd_lock_wait kernel/smp.c:340 [inline] smp_call_function_many_cond+0xf80/0x12d0 kernel/smp.c:885 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2691 [inline] smp_text_poke_batch_finish+0x5e0/0x1100 arch/x86/kernel/alternative.c:2901 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x128/0x250 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:850 process_one_work kernel/workqueue.c:3239 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3322 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3403 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245