rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=6814/1/0x4000000000000000 softirq=69567/69568 fqs=0 rcu: (detected by 0, t=10502 jiffies, g=69161, q=114 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 13261 Comm: syz.7.1747 Not tainted 6.16.0-rc1-next-20250613-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:advance_sched+0x178/0xc90 net/sched/sch_taprio.c:927 Code: db 74 29 49 8d 7c 24 c0 be ff ff ff ff e8 70 63 e0 01 89 c3 31 ff 89 c6 e8 75 ed 37 f8 85 db 0f 84 ab 06 00 00 e8 28 e9 37 f8 05 e8 21 e9 37 f8 4d 8d 74 24 f0 4c 89 f1 48 c1 e9 03 48 b8 00 RSP: 0018:ffffc90000a08c70 EFLAGS: 00000006 RAX: ffffffff89887e68 RBX: 0000000000000001 RCX: ffff88806b581e00 RDX: 0000000000010000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff5200014117c R12: ffff88807a5a7340 R13: ffff88807a5a7000 R14: dffffc0000000000 R15: ffff888034d33800 FS: 00007fb9ebb0f6c0(0000) GS:ffff888125d41000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0ee9a23d58 CR3: 000000003ee0a000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __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:trace_lock_acquire include/trace/events/lock.h:24 [inline] RIP: 0010:lock_acquire+0x58/0x360 kernel/locking/lockdep.c:5834 Code: 8b 05 dc bd ff 10 48 89 44 24 58 0f 1f 44 00 00 65 8b 05 df bd ff 10 83 f8 08 0f 83 b8 01 00 00 89 c0 48 0f a3 05 88 25 03 0e <73> 16 e8 51 f3 08 00 84 c0 75 0d f6 05 c6 15 ed 0d 01 0f 84 d7 01 RSP: 0018:ffffc90004cfebf8 EFLAGS: 00000297 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e13ee20 RBP: ffffffff81729af5 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc90004cfedb8 R11: ffffffff81acfbf0 R12: 0000000000000002 R13: ffffffff8e13ee20 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:156 __set_page_owner+0x8d/0x4a0 mm/page_owner.c:329 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704 prep_new_page mm/page_alloc.c:1712 [inline] get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3669 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2438 shmem_alloc_folio mm/shmem.c:1847 [inline] shmem_alloc_and_add_folio+0x447/0xf60 mm/shmem.c:1886 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2532 shmem_fault+0x179/0x390 mm/shmem.c:2733 __do_fault+0x135/0x390 mm/memory.c:5187 do_read_fault mm/memory.c:5608 [inline] do_fault mm/memory.c:5742 [inline] do_pte_missing mm/memory.c:4269 [inline] handle_pte_fault mm/memory.c:6087 [inline] __handle_mm_fault+0x37ed/0x5620 mm/memory.c:6230 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6399 faultin_page mm/gup.c:1186 [inline] __get_user_pages+0x1aef/0x30b0 mm/gup.c:1488 populate_vma_page_range+0x29f/0x3a0 mm/gup.c:1922 __mm_populate+0x24c/0x380 mm/gup.c:2025 mm_populate include/linux/mm.h:3354 [inline] vm_mmap_pgoff+0x3f0/0x4c0 mm/util.c:584 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: 0033:0x7fb9ead8e929 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:00007fb9ebb0f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007fb9eafb5fa0 RCX: 00007fb9ead8e929 RDX: b635773f06ebbeef RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007fb9eae10b39 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fb9eafb5fa0 R15: 00007ffdb1799a58 rcu: rcu_preempt kthread starved for 10502 jiffies! g69161 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: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:2060 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2262 kthread+0x711/0x8a0 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: 13263 Comm: syz.5.1746 Not tainted 6.16.0-rc1-next-20250613-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 e0 7d 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 8b 79 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 70 79 0b RSP: 0018:ffffc900046ff360 EFLAGS: 00000293 RAX: ffffffff81b4ee20 RBX: ffff8880b863cb40 RCX: ffff88806ea03c00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900046ff4c0 R08: ffffffff8fa157f7 R09: 1ffffffff1f42afe R10: dffffc0000000000 R11: fffffbfff1f42aff R12: 1ffff110170e828d R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8880b8741468 FS: 0000000000000000(0000) GS:ffff888125c41000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c44e079 CR3: 000000000df38000 CR4: 00000000003526f0 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 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline] tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497 free_ldt_pgtables+0x17b/0x320 arch/x86/kernel/ldt.c:411 arch_exit_mmap arch/x86/include/asm/mmu_context.h:234 [inline] exit_mmap+0x17c/0xb50 mm/mmap.c:1270 __mmput+0x118/0x420 kernel/fork.c:1120 exit_mm+0x1da/0x2c0 kernel/exit.c:581 do_exit+0x648/0x22e0 kernel/exit.c:952 do_group_exit+0x21c/0x2d0 kernel/exit.c:1105 get_signal+0x1286/0x1340 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x75/0x110 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+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6d0798e929 Code: Unable to access opcode bytes at 0x7f6d0798e8ff. RSP: 002b:00007f6d088d40e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000001 RBX: 00007f6d07bb5fa8 RCX: 00007f6d0798e929 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f6d07bb5fac RBP: 00007f6d07bb5fa0 R08: 7fffffffffffffff R09: 0000000000000000 R10: 000000000000001c R11: 0000000000000246 R12: 00007f6d07bb5fac R13: 0000000000000000 R14: 00007ffc938b5710 R15: 00007ffc938b57f8