rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5996/1:b..l P6157/1:b..l P5843/1:b..l rcu: (detected by 0, t=10502 jiffies, g=25317, q=1497 ncpus=2) task:udevd state:R running task stack:24936 pid:5843 tgid:5843 ppid:5217 task_flags:0x40014c flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288 irqentry_exit+0x36/0x90 kernel/entry/common.c:197 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:406 [inline] RIP: 0010:unwind_next_frame+0x15f1/0x20a0 arch/x86/kernel/unwind_orc.c:648 Code: 0f 84 b5 ed ff ff 48 89 ef e8 0b e0 ff ff 49 8d 7d 40 48 89 fa 48 89 c5 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 <0f> 84 cb f9 ff ff e8 f4 ee b6 00 e9 c1 f9 ff ff 48 b8 00 00 00 00 RSP: 0018:ffffc900039e7440 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffc900039e8000 RDX: 1ffff9200073ce9e RSI: ffffc900039e7d88 RDI: ffffc900039e74f0 RBP: ffff888022f062c8 R08: 0000000000000001 R09: 0000000000000000 R10: ffffc900039e74b0 R11: 0000000000010b2d R12: ffffc900039e7500 R13: ffffc900039e74b0 R14: ffffc900039e7db8 R15: ffffc900039e74e4 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x160/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x84/0x1a0 mm/page_owner.c:308 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] free_unref_folios+0xa61/0x16b0 mm/page_alloc.c:2952 folios_put_refs+0x56f/0x740 mm/swap.c:997 free_pages_and_swap_cache+0x245/0x4a0 mm/swap_state.c:264 __tlb_batch_free_encoded_pages+0xf9/0x290 mm/mmu_gather.c:136 tlb_batch_pages_flush mm/mmu_gather.c:149 [inline] tlb_flush_mmu_free mm/mmu_gather.c:397 [inline] tlb_flush_mmu mm/mmu_gather.c:404 [inline] tlb_finish_mmu+0x168/0x7c0 mm/mmu_gather.c:497 exit_mmap+0x403/0xb90 mm/mmap.c:1293 __mmput+0x12a/0x410 kernel/fork.c:1130 mmput+0x62/0x70 kernel/fork.c:1152 exit_mm kernel/exit.c:582 [inline] do_exit+0x7c7/0x2bf0 kernel/exit.c:949 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102 __do_sys_exit_group kernel/exit.c:1113 [inline] __se_sys_exit_group kernel/exit.c:1111 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111 x64_sys_call+0x14fa/0x1720 arch/x86/include/generated/asm/syscalls_64.h:232 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: 0033:0x7fccdf0f16c5 RSP: 002b:00007ffeb0d4ba08 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000557136e6bb60 RCX: 00007fccdf0f16c5 RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000 RBP: 0000557136c1b2c0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffeb0d4ba50 R14: 0000000000000000 R15: 0000000000000000 task:udevd state:R running task stack:26408 pid:6157 tgid:6157 ppid:5217 task_flags:0x40014c flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 preempt_schedule_notrace+0x62/0xe0 kernel/sched/core.c:7238 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x8e/0xc0 kernel/rcu/tree.c:752 trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0x201/0x2f0 kernel/locking/lockdep.c:5879 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0x3f9/0x20a0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:548 __call_rcu_common.constprop.0+0xa5/0xa10 kernel/rcu/tree.c:3123 slab_free_hook mm/slub.c:2381 [inline] slab_free mm/slub.c:4680 [inline] kmem_cache_free+0x16d/0x4d0 mm/slub.c:4782 exit_mmap+0x511/0xb90 mm/mmap.c:1305 __mmput+0x12a/0x410 kernel/fork.c:1130 mmput+0x62/0x70 kernel/fork.c:1152 exit_mm kernel/exit.c:582 [inline] do_exit+0x7c7/0x2bf0 kernel/exit.c:949 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102 __do_sys_exit_group kernel/exit.c:1113 [inline] __se_sys_exit_group kernel/exit.c:1111 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111 x64_sys_call+0x14fa/0x1720 arch/x86/include/generated/asm/syscalls_64.h:232 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: 0033:0x7fccdf0f16c5 RSP: 002b:00007ffeb0d4ba08 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000557136e8ca40 RCX: 00007fccdf0f16c5 RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000 RBP: 0000557136c1b2c0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffeb0d4ba50 R14: 0000000000000000 R15: 0000000000000000 task:udevd state:R running task stack:26896 pid:5996 tgid:5996 ppid:5217 task_flags:0x40014c flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288 irqentry_exit+0x36/0x90 kernel/entry/common.c:197 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:its_return_thunk+0x0/0x10 arch/x86/lib/retpoline.S:412 Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 e9 db 7e 95 f5 cc RSP: 0018:ffffc9000485f6a8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 00000000000518d2 RCX: ffffffff822d8f31 RDX: ffff888035b18000 RSI: ffffffff822d8f3f RDI: 0000000000000006 RBP: 0000000000000000 R08: 0000000000000006 R09: 0000000000001000 R10: 0000000000000000 R11: 0000000000000001 R12: 000000000000000a R13: 0000000000001000 R14: 0000000000000000 R15: ffffea0001463480 __nr_to_section include/linux/mmzone.h:1941 [inline] __pfn_to_section include/linux/mmzone.h:2079 [inline] lookup_page_ext+0x6f/0x1d0 mm/page_ext.c:251 page_ext_get+0x58/0x1a0 mm/page_ext.c:528 __reset_page_owner+0x2b/0x1a0 mm/page_owner.c:294 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] free_unref_folios+0xa61/0x16b0 mm/page_alloc.c:2952 folios_put_refs+0x56f/0x740 mm/swap.c:997 free_pages_and_swap_cache+0x245/0x4a0 mm/swap_state.c:264 __tlb_batch_free_encoded_pages+0xf9/0x290 mm/mmu_gather.c:136 tlb_batch_pages_flush mm/mmu_gather.c:149 [inline] tlb_flush_mmu_free mm/mmu_gather.c:397 [inline] tlb_flush_mmu mm/mmu_gather.c:404 [inline] tlb_finish_mmu+0x168/0x7c0 mm/mmu_gather.c:497 exit_mmap+0x403/0xb90 mm/mmap.c:1293 __mmput+0x12a/0x410 kernel/fork.c:1130 mmput+0x62/0x70 kernel/fork.c:1152 exit_mm kernel/exit.c:582 [inline] do_exit+0x7c7/0x2bf0 kernel/exit.c:949 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102 __do_sys_exit_group kernel/exit.c:1113 [inline] __se_sys_exit_group kernel/exit.c:1111 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111 x64_sys_call+0x14fa/0x1720 arch/x86/include/generated/asm/syscalls_64.h:232 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: 0033:0x7fccdf0f16c5 RSP: 002b:00007ffeb0d4ba08 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000557136e6c4a0 RCX: 00007fccdf0f16c5 RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000 RBP: 0000557136c1b2c0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffeb0d4ba50 R14: 0000000000000000 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 9969 jiffies! g25317 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 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:28000 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7058 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.17.0-rc2-syzkaller-00028-gbe48bcf004f9 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: 5c 62 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 d3 72 16 00 fb f4 4c 09 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197df8 EFLAGS: 000002c2 RAX: 0000000000b3fc2c RBX: 0000000000000001 RCX: ffffffff8b939c29 RDX: ffffed10170a6656 RSI: ffffffff8c162880 RDI: ffffffff819133c1 RBP: ffffed1003c5d488 R08: 0000000000000000 R09: ffffed10170a6655 R10: ffff8880b85332ab R11: 0000000000000001 R12: 0000000000000001 R13: ffff88801e2ea440 R14: ffffffff90ab3f90 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881247bc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005652e5669000 CR3: 0000000072505000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:757 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x391/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428 start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x148 sched: DL replenish lagged too much