rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=463c/1/0x4000000000000000 softirq=104036/104041 fqs=0 rcu: (detected by 0, t=10505 jiffies, g=82133, q=1146 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 18156 Comm: syz.0.2859 Not tainted 6.16.0-rc5-syzkaller-00266-g3f31a806a62e #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:rb_next+0x0/0x130 lib/rbtree.c:493 Code: 4c 24 08 48 89 14 24 e8 7e b1 9e f6 48 8b 4c 24 08 48 8b 14 24 e9 6c fc ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 b8 00 00 00 00 00 fc ff df 41 54 48 89 fa 55 48 c1 RSP: 0018:ffffc90000a08dd8 EFLAGS: 00000046 RAX: 0000000080010002 RBX: ffff8880337d2340 RCX: ffffffff8b847d70 RDX: ffff8880227b4880 RSI: ffffffff8b847e00 RDI: ffff8880337d2340 RBP: ffff8880b8527d50 R08: 0000000000000006 R09: ffff8880b8528a60 R10: ffff8880337d2340 R11: 0000000000000001 R12: ffff8880b8527d58 R13: 0000000000000000 R14: ffff8880b8527c80 R15: 0000000000000000 FS: 00007fd6db7506c0(0000) GS:ffff888124813000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000562fd9a01be0 CR3: 00000000738b7000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000040020 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: rb_erase_cached include/linux/rbtree.h:124 [inline] timerqueue_del+0xd8/0x150 lib/timerqueue.c:57 __remove_hrtimer+0x99/0x290 kernel/time/hrtimer.c:1121 __run_hrtimer kernel/time/hrtimer.c:1741 [inline] __hrtimer_run_queues+0x4f9/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:finish_task_switch.isra.0+0x22a/0xc10 kernel/sched/core.c:5265 Code: fb 09 00 00 44 8b 05 09 cb 1f 0f 45 85 c0 0f 85 be 01 00 00 4c 89 e7 e8 a4 f6 ff ff e8 df d5 39 00 fb 65 48 8b 1d be e2 46 12 <48> 8d bb 18 16 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 RSP: 0018:ffffc9000427f6f8 EFLAGS: 00000206 RAX: 0000000000009565 RBX: ffff8880227b4880 RCX: ffffffff81c3c22f RDX: 0000000000000000 RSI: ffffffff8de32e47 RDI: ffffffff8c158f60 RBP: ffffc9000427f740 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff90a98657 R11: 0000000000000001 R12: ffff8880b853a2c0 R13: ffff88801e2da440 R14: 0000000000000001 R15: ffff8880b853b130 context_switch kernel/sched/core.c:5400 [inline] __schedule+0x1172/0x5de0 kernel/sched/core.c:6786 __schedule_loop kernel/sched/core.c:6864 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6879 schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:95 [inline] __wait_for_common+0x2ff/0x4e0 kernel/sched/completion.c:116 rdmsr_safe_on_cpu+0x1dc/0x210 arch/x86/lib/msr-smp.c:181 msr_read+0x19d/0x250 arch/x86/kernel/msr.c:66 vfs_read+0x1e1/0xc60 fs/read_write.c:570 ksys_read+0x12a/0x250 fs/read_write.c:715 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd6da98e929 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:00007fd6db750038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007fd6dabb5fa0 RCX: 00007fd6da98e929 RDX: 0000000000018ff8 RSI: 0000200000004c00 RDI: 0000000000000003 RBP: 00007fd6daa10b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fd6dabb5fa0 R15: 00007fff681076d8 rcu: rcu_preempt kthread starved for 10505 jiffies! g82133 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:27672 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6786 __schedule_loop kernel/sched/core.c:6864 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6879 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d7/0x6f0 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: 18166 Comm: syz.1.2861 Not tainted 6.16.0-rc5-syzkaller-00266-g3f31a806a62e #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+0xd7b/0x1510 kernel/smp.c:885 Code: e8 6a 19 0c 00 45 85 ed 74 46 48 8b 14 24 49 89 d6 49 89 d5 49 c1 ee 03 41 83 e5 07 4d 01 e6 41 83 c5 03 e8 07 1e 0c 00 f3 90 <41> 0f b6 06 41 38 c5 7c 08 84 c0 0f 85 6f 05 00 00 8b 43 08 31 ff RSP: 0018:ffffc900034773b0 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b853fe20 RCX: ffffffff81afd49d RDX: ffff88802c704880 RSI: ffffffff81afd479 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000 R13: 0000000000000003 R14: ffffed10170a7fc5 R15: ffff8880b843b580 FS: 0000000000000000(0000) GS:ffff888124713000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd290981ab8 CR3: 000000005800c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000040020 DR3: 0000000000000000 DR6: 00000000ffff0ff0 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:1361 [inline] flush_tlb_mm_range+0x4a0/0x1790 arch/x86/mm/tlb.c:1451 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:480 [inline] zap_pte_range mm/memory.c:1762 [inline] zap_pmd_range mm/memory.c:1827 [inline] zap_pud_range mm/memory.c:1856 [inline] zap_p4d_range mm/memory.c:1877 [inline] unmap_page_range+0x21af/0x4350 mm/memory.c:1898 unmap_single_vma.constprop.0+0x153/0x240 mm/memory.c:1941 unmap_vmas+0x218/0x470 mm/memory.c:1985 exit_mmap+0x1b9/0xb90 mm/mmap.c:1284 __mmput+0x12a/0x410 kernel/fork.c:1121 mmput+0x62/0x70 kernel/fork.c:1144 exit_mm kernel/exit.c:581 [inline] do_exit+0x7c4/0x2bd0 kernel/exit.c:952 do_group_exit+0xd3/0x2a0 kernel/exit.c:1105 get_signal+0x2673/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:111 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline] do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd65938e929 Code: Unable to access opcode bytes at 0x7fd65938e8ff. RSP: 002b:00007fd65a1a3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: 000000000000000b RBX: 00007fd6595b5fa0 RCX: 00007fd65938e929 RDX: 0000000000000318 RSI: 00002000000bd000 RDI: 0000000000000004 RBP: 00007fd659410b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fd6595b5fa0 R15: 00007ffd1bfd36e8