rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...0: (3 ticks this GP) idle=391c/0/0x1 softirq=14929/14930 fqs=2003 rcu: hardirqs softirqs csw/system rcu: number: 0 0 0 rcu: cputime: 0 0 0 ==> 52500(ms) rcu: (detected by 0, t=10505 jiffies, g=8821, q=143 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.15.0-rc2-syzkaller-00257-gb5c6891b2c5b #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:121 [inline] RIP: 0010:lock_is_held_type+0x2d/0x150 kernel/locking/lockdep.c:5931 Code: fa 41 57 41 56 41 55 41 bd ff ff ff ff 41 54 55 53 48 83 ec 08 8b 0d 46 11 14 05 85 c9 0f 84 dd 00 00 00 65 8b 05 0b b8 34 08 <85> c0 0f 85 ce 00 00 00 65 4c 8b 25 8b 7a 34 08 41 8b 94 24 ec 0a RSP: 0018:ffffc90000a08d50 EFLAGS: 00000002 RAX: 0000000000000000 RBX: ffff88807608c340 RCX: 0000000000000001 RDX: ffff88801dae2440 RSI: 00000000ffffffff RDI: ffff88807608c300 RBP: ffff88803567f400 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001 R13: 00000000ffffffff R14: ffff88807608c340 R15: ffffffff8982a1f0 FS: 0000000000000000(0000) GS:ffff888124ab0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000078574000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_is_held include/linux/lockdep.h:249 [inline] advance_sched+0x721/0xc80 net/sched/sch_taprio.c:929 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x1ff/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x108/0x3f0 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:81 Code: 45 5d 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 93 5c 17 00 fb f4 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197df8 EFLAGS: 000002c6 RAX: 000000000006f90b RBX: 0000000000000001 RCX: ffffffff8b729439 RDX: 0000000000000000 RSI: ffffffff8dbef927 RDI: ffffffff8bf464c0 RBP: ffffed1003b5c488 R08: 0000000000000001 R09: ffffed10170a65bd R10: ffff8880b8532deb R11: 0000000000000000 R12: 0000000000000001 R13: ffff88801dae2440 R14: ffffffff90866710 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:748 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x391/0x510 kernel/sched/idle.c:325 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:423 start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x148 rcu: rcu_preempt kthread starved for 490 jiffies! g8821 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:28712 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2046 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2248 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 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: 5493 Comm: dhcpcd Not tainted 6.15.0-rc2-syzkaller-00257-gb5c6891b2c5b #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0x4a5/0x1290 kernel/smp.c:885 Code: 89 ee e8 5e 12 0c 00 85 ed 74 48 48 8b 44 24 20 49 89 c4 83 e0 07 49 c1 ec 03 48 89 c5 4d 01 f4 83 c5 03 e8 fd 16 0c 00 f3 90 <41> 0f b6 04 24 40 38 c5 7c 08 84 c0 0f 85 de 0b 00 00 8b 43 08 31 RSP: 0018:ffffc90003ebf8b8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b853f740 RCX: ffffffff81af2699 RDX: ffff88802e42c880 RSI: ffffffff81af2673 RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffed10170a7ee9 R13: 0000000000000001 R14: dffffc0000000000 R15: ffff8880b843b040 FS: 00007f8a2de55740(0000) GS:ffff8881249b0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8a2e001580 CR3: 000000002a412000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1275 [inline] flush_tlb_mm_range+0x322/0x1780 arch/x86/mm/tlb.c:1365 dup_mmap kernel/fork.c:765 [inline] dup_mm kernel/fork.c:1734 [inline] copy_mm kernel/fork.c:1786 [inline] copy_process+0x7961/0x91a0 kernel/fork.c:2429 kernel_clone+0xfc/0x960 kernel/fork.c:2844 __do_sys_clone+0xce/0x120 kernel/fork.c:2987 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8a2df05a12 Code: 41 5d 41 5e 41 5f c3 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 76 10 48 8b 15 e7 43 0f 00 f7 d8 64 89 02 48 83 RSP: 002b:00007fffe26f61c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000558010850d01 RCX: 00007f8a2df05a12 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007fffe2716738 R08: 0000000000000000 R09: 0000558010850d40 R10: 00007f8a2de55a10 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000558010850d74