rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11330/1:b..l P11384/1:b..l rcu: (detected by 0, t=10502 jiffies, g=56737, q=408 ncpus=2) task:dhcpcd state:R running task stack:24824 pid:11384 tgid:11384 ppid:5495 task_flags:0x400040 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7090 irqentry_exit+0x6f/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__rcu_read_unlock+0xa/0xe0 kernel/rcu/tree_plugin.h:431 Code: 7c dc 48 89 df e8 76 18 7a 00 eb d2 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 55 <41> 54 53 49 bf 00 00 00 00 00 fc ff df 65 48 8b 3c 25 08 90 75 92 RSP: 0018:ffffc9000bd17280 EFLAGS: 00000282 RAX: eb1f38ec885f1a00 RBX: ffffffff81ab5cfd RCX: eb1f38ec885f1a00 RDX: 0000000000000001 RSI: ffffffff8d936f16 RDI: ffffffff8bc1d820 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff81ab5cfd R12: ffff88802f9f9e00 R13: 0000000000000000 R14: 00007fcdc90b52e7 R15: 1ffff920017a2e6e rcu_read_unlock include/linux/rcupdate.h:873 [inline] class_rcu_destructor include/linux/rcupdate.h:1155 [inline] is_module_text_address+0x190/0x1e0 kernel/module/main.c:3745 kernel_text_address+0x94/0xe0 kernel/extable.c:119 __kernel_text_address+0xd/0x40 kernel/extable.c:79 unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0xfc/0x150 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:548 slab_free_hook mm/slub.c:2341 [inline] slab_free mm/slub.c:4642 [inline] kmem_cache_free+0x2ee/0x3f0 mm/slub.c:4744 anon_vma_free mm/rmap.c:137 [inline] __put_anon_vma+0x12b/0x2d0 mm/rmap.c:2756 put_anon_vma include/linux/rmap.h:117 [inline] unlink_anon_vmas+0x503/0x670 mm/rmap.c:444 free_pgtables+0x45d/0x710 mm/memory.c:391 vms_clear_ptes+0x424/0x540 mm/vma.c:1189 vms_complete_munmap_vmas+0x206/0x8a0 mm/vma.c:1233 do_vmi_align_munmap+0x358/0x420 mm/vma.c:1492 do_vmi_munmap+0x253/0x2e0 mm/vma.c:1540 __vm_munmap+0x23b/0x3d0 mm/vma.c:3013 __do_sys_munmap mm/mmap.c:1084 [inline] __se_sys_munmap mm/mmap.c:1081 [inline] __x64_sys_munmap+0x60/0x70 mm/mmap.c:1081 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcdc90b52e7 RSP: 002b:00007ffdb67a08e8 EFLAGS: 00000202 ORIG_RAX: 000000000000000b RAX: ffffffffffffffda RBX: 0000558cfde71a10 RCX: 00007fcdc90b52e7 RDX: 0000000000000001 RSI: 0000000000029910 RDI: 00007fcdc8e77000 RBP: 00007ffdb67a09f0 R08: 00000000000004f0 R09: 0000000000000002 R10: 00007ffdb67a0820 R11: 0000000000000202 R12: 00007ffdb67a0928 R13: 00007fcdc90c8000 R14: 0000558cfde71a10 R15: 0000000000000000 task:syz.3.1643 state:R running task stack:25048 pid:11330 tgid:11326 ppid:5848 task_flags:0x40044c flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6947 preempt_schedule+0xae/0xc0 kernel/sched/core.c:6971 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1761 [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+0x3756/0x4210 mm/memory.c:1894 unmap_vmas+0x25d/0x3c0 mm/memory.c:1984 exit_mmap+0x245/0xba0 mm/mmap.c:1284 __mmput+0x118/0x420 kernel/fork.c:1379 exit_mm+0x1da/0x2c0 kernel/exit.c:589 do_exit+0x859/0x2550 kernel/exit.c:940 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102 get_signal+0x125e/0x1310 kernel/signal.c:3034 arch_do_signal_or_restart+0x95/0x780 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+0x8b/0x120 kernel/entry/common.c:218 do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8fe1d8e969 RSP: 002b:00007f8fe2c1a038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: 0000000000010106 RBX: 00007f8fe1fb6080 RCX: 00007f8fe1d8e969 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000004 RBP: 00007f8fe1e10ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f8fe1fb6080 R15: 00007f8fe20dfa28 rcu: rcu_preempt kthread starved for 9792 jiffies! g56737 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:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2046 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2248 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/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: 0 Comm: swapper/0 Not tainted 6.15.0-rc6-syzkaller-00047-ge9565e23cd89 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81 Code: c3 d4 02 00 cc cc cc 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 a3 cf 11 00 f3 0f 1e fa fb f4 98 d4 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8dc07d80 EFLAGS: 000002c6 RAX: 2eff9b21d8e39f00 RBX: ffffffff81977128 RCX: 2eff9b21d8e39f00 RDX: 0000000000000001 RSI: ffffffff8d74c01e RDI: ffffffff8bc1d820 RBP: ffffffff8dc07ec0 R08: ffff8880b8832b5b R09: 1ffff1101710656b R10: dffffc0000000000 R11: ffffed101710656c R12: ffffffff8f7efb70 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1b92a48 FS: 0000000000000000(0000) GS:ffff8881260c7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc6965180e2 CR3: 0000000031b40000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:748 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x1e8/0x510 kernel/sched/idle.c:325 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:423 rest_init+0x2de/0x300 init/main.c:743 start_kernel+0x470/0x4f0 init/main.c:1099 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:513 x86_64_start_kernel+0x66/0x70 arch/x86/kernel/head64.c:494 common_startup_64+0x13e/0x147