rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=299c/1/0x4000000000000000 softirq=34401/34403 fqs=3 rcu: (detected by 0, t=10502 jiffies, g=27657, q=463 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 9022 Comm: syz.3.984 Not tainted 6.15.0-rc2-syzkaller-00278-gfc96b232f8e7 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:lookup_object lib/debugobjects.c:-1 [inline] RIP: 0010:lookup_object_or_alloc lib/debugobjects.c:662 [inline] RIP: 0010:debug_object_activate+0x195/0x5c0 lib/debugobjects.c:820 Code: e9 2f 83 e1 f8 48 8d 1c c9 48 81 c3 a0 0f 90 9a 48 8d 3c c9 48 81 c7 a8 0f 90 9a 48 89 7c 24 10 e8 b0 1f 27 07 48 89 44 24 08 <48> 89 d8 48 c1 e8 03 42 80 3c 30 00 74 08 48 89 df e8 15 bb 21 fd RSP: 0018:ffffc90000a08be0 EFLAGS: 00000046 RAX: 0000000000000046 RBX: ffffffff9a992a10 RCX: 0000000000000001 RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffffc90000a08ac0 RBP: ffffc90000a08cf8 R08: 0000000000000003 R09: fffff52000141158 R10: dffffc0000000000 R11: fffff52000141158 R12: ffff888029d85340 R13: 0000000000000000 R14: dffffc0000000000 R15: ffffffff93686020 FS: 0000000000000000(0000) GS:ffff88812509a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000003c80 CR3: 0000000043fd0000 CR4: 0000000000350ef0 Call Trace: debug_hrtimer_activate kernel/time/hrtimer.c:445 [inline] debug_activate kernel/time/hrtimer.c:484 [inline] enqueue_hrtimer+0x30/0x3c0 kernel/time/hrtimer.c:1088 __run_hrtimer kernel/time/hrtimer.c:1778 [inline] __hrtimer_run_queues+0x6d6/0xd40 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x112/0x420 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:_compound_head include/linux/page-flags.h:282 [inline] RIP: 0010:__folio_rmap_sanity_checks+0x108/0x710 include/linux/rmap.h:426 Code: 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 b9 5c 12 00 48 8b 1b 48 89 de 48 83 e6 01 31 ff e8 98 22 a8 ff <48> 89 d8 48 83 e0 01 0f 85 2e 03 00 00 0f 1f 44 00 00 e8 a1 1d a8 RSP: 0018:ffffc90003c0f160 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88801efa0000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00000000000136c4 R08: ffffffff821a9d08 R09: 1ffffd40003af308 R10: dffffc0000000000 R11: fffff940003af309 R12: ffffea0001d79840 R13: ffffea0001d79840 R14: 0000000000000001 R15: 0000000000000000 __folio_remove_rmap mm/rmap.c:1694 [inline] folio_remove_rmap_ptes+0x3d/0xa70 mm/rmap.c:1804 zap_present_folio_ptes mm/memory.c:1525 [inline] zap_present_ptes mm/memory.c:1586 [inline] do_zap_pte_range mm/memory.c:1687 [inline] zap_pte_range mm/memory.c:1731 [inline] zap_pmd_range mm/memory.c:1823 [inline] zap_pud_range mm/memory.c:1852 [inline] zap_p4d_range mm/memory.c:1873 [inline] unmap_page_range+0x21cf/0x44d0 mm/memory.c:1894 unmap_vmas+0x3ce/0x5f0 mm/memory.c:1984 exit_mmap+0x2bc/0xde0 mm/mmap.c:1284 __mmput+0x115/0x420 kernel/fork.c:1379 exit_mm+0x221/0x310 kernel/exit.c:589 do_exit+0x994/0x27f0 kernel/exit.c:940 do_group_exit+0x207/0x2c0 kernel/exit.c:1102 get_signal+0x1696/0x1730 kernel/signal.c:3034 arch_do_signal_or_restart+0x98/0x810 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x210 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbf2e38e169 Code: Unable to access opcode bytes at 0x7fbf2e38e13f. RSP: 002b:00007fbf2f1610e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fbf2e5b5fa8 RCX: 00007fbf2e38e169 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fbf2e5b5fa8 RBP: 00007fbf2e5b5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fbf2e5b5fac R13: 0000000000000000 R14: 00007fff6ae315e0 R15: 00007fff6ae316c8 rcu: rcu_preempt kthread starved for 10496 jiffies! g27657 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:26688 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x163/0x360 kernel/sched/core.c:6860 schedule_timeout+0x15b/0x2b0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2e1/0x1340 kernel/rcu/tree.c:2046 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2248 kthread+0x7b9/0x940 kernel/kthread.c:464 ret_from_fork+0x4d/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: 5836 Comm: syz-executor Not tainted 6.15.0-rc2-syzkaller-00278-gfc96b232f8e7 #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+0x1bb6/0x2d40 kernel/smp.c:885 Code: 89 e6 83 e6 01 31 ff e8 68 dc 0b 00 41 83 e4 01 4c 8b 64 24 68 75 07 e8 18 d8 0b 00 eb 41 f3 90 48 b8 00 00 00 00 00 fc ff df <0f> b6 04 03 84 c0 75 11 41 f7 45 00 01 00 00 00 74 1e e8 f3 d7 0b RSP: 0018:ffffc90003d0f4c0 EFLAGS: 00000293 RAX: dffffc0000000000 RBX: 1ffff110170e7e91 RCX: ffff88807afcbc00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90003d0f6c0 R08: ffffffff81b6e298 R09: 1ffffffff20bfcce R10: dffffc0000000000 R11: fffffbfff20bfccf R12: ffff8880b863ad08 R13: ffff8880b873f488 R14: ffff8880b863ad00 R15: 0000000000000001 FS: 000055558c93c500(0000) GS:ffff888124f9a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000007f9030 CR3: 000000005de8c000 CR4: 0000000000350ef0 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:1275 [inline] flush_tlb_mm_range+0xb8d/0x13f0 arch/x86/mm/tlb.c:1365 dup_mmap kernel/fork.c:765 [inline] dup_mm kernel/fork.c:1734 [inline] copy_mm+0x19de/0x22c0 kernel/fork.c:1786 copy_process+0x17de/0x3d10 kernel/fork.c:2429 kernel_clone+0x242/0x930 kernel/fork.c:2844 __do_sys_clone kernel/fork.c:2987 [inline] __se_sys_clone kernel/fork.c:2971 [inline] __x64_sys_clone+0x268/0x2e0 kernel/fork.c:2971 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f93721849d3 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:00007ffc6b91eed8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f93721849d3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 000055558c93c7d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 0000000000046271 R15: 00007ffc6b91f070