rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=278c/1/0x4000000000000000 softirq=38004/38018 fqs=1 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9388/1:b..l P8458/1:b..l rcu: (detected by 0, t=10502 jiffies, g=30169, q=549 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 9399 Comm: syz.2.1062 Not tainted 6.15.0-rc1-syzkaller #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 e0 4f 90 9a 48 8d 3c c9 48 81 c7 e8 4f 90 9a 48 89 7c 24 10 e8 40 22 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 62 21 fd RSP: 0018:ffffc90000a08be0 EFLAGS: 00000046 RAX: 0000000000000046 RBX: ffffffff9a942840 RCX: 0000000000000001 RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffffc90000a08ac0 RBP: ffffc90000a08cf8 R08: 0000000000000003 R09: fffff52000141158 R10: dffffc0000000000 R11: fffff52000141158 R12: ffff88805a2fe340 R13: 0000000000000000 R14: dffffc0000000000 R15: ffffffff9368a020 FS: 0000000000000000(0000) GS:ffff888125096000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000003c80 CR3: 00000000790c6000 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:rcu_read_lock_sched include/linux/rcupdate.h:933 [inline] RIP: 0010:pfn_valid+0x117/0x450 include/linux/mmzone.h:2116 Code: 57 ff 4c 8d 35 00 00 00 00 48 c7 c7 60 df d3 8e 31 f6 31 d2 b9 02 00 00 00 45 31 c0 45 31 c9 41 56 e8 3d 82 65 ff 48 83 c4 08 f4 1c f7 09 89 c5 31 ff 89 c6 e8 59 ed 89 ff 85 ed 74 1a e8 00 RSP: 0018:ffffc90012c77410 EFLAGS: 00000292 RAX: 056d07e81e481a00 RBX: 0000000000000180 RCX: 056d07e81e481a00 RDX: 0000000000000000 RSI: ffffffff8e4fd4cc RDI: ffffffff8ca1b620 RBP: ffff88823ffef400 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: 0000000000061277 R14: ffffffff82396bd6 R15: ffff88813fffa580 page_table_check_clear+0x21/0x6f0 mm/page_table_check.c:70 ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline] get_and_clear_full_ptes include/linux/pgtable.h:714 [inline] zap_present_folio_ptes mm/memory.c:1501 [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+0x33cf/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 __do_sys_exit_group kernel/exit.c:1113 [inline] __se_sys_exit_group kernel/exit.c:1111 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1111 x64_sys_call+0x26c3/0x26d0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb6d5f8d169 Code: Unable to access opcode bytes at 0x7fb6d5f8d13f. RSP: 002b:00007fff6d362778 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb6d5f8d169 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fff6d3627dc R08: 000000046d36286f R09: 00000000000927c0 R10: 0000000000000001 R11: 0000000000000246 R12: 00000000000000c0 R13: 00000000000927c0 R14: 0000000000041018 R15: 00007fff6d362830 task:syz-executor state:R running task stack:21064 pid:8458 tgid:8458 ppid:8437 task_flags:0x400140 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 preempt_schedule_irq+0xfe/0x1c0 kernel/sched/core.c:7090 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lookup_page_ext mm/page_ext.c:254 [inline] RIP: 0010:page_ext_lookup+0xef/0x150 mm/page_ext.c:520 Code: 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 f6 3a f4 ff 4c 8b 33 e8 de 2b 6e ff 89 c3 31 ff 89 c6 e8 03 16 8a ff 85 db <74> 52 e8 ba 11 8a ff 44 89 f3 83 e3 01 31 ff 48 89 de e8 8a 16 8a RSP: 0018:ffffc9000ac67410 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000080000000 RDX: ffff8880275f0000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: dffffc0000000000 R08: ffffffff8239435d R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: 00000000000365d0 R14: ffff88801bd00000 R15: 00000000000365d0 page_ext_iter_begin include/linux/page_ext.h:132 [inline] __page_table_check_zero+0x16c/0x510 mm/page_table_check.c:139 page_table_check_free include/linux/page_table_check.h:41 [inline] free_pages_prepare mm/page_alloc.c:1263 [inline] free_unref_folios+0xe22/0x17f0 mm/page_alloc.c:2737 folios_put_refs+0x70a/0x800 mm/swap.c:992 folio_batch_release include/linux/pagevec.h:101 [inline] shmem_undo_range+0x595/0x1820 mm/shmem.c:1125 shmem_truncate_range mm/shmem.c:1237 [inline] shmem_evict_inode+0x29d/0xa80 mm/shmem.c:1365 evict+0x4fb/0x9b0 fs/inode.c:810 __dentry_kill+0x20d/0x630 fs/dcache.c:660 dput+0x19f/0x2b0 fs/dcache.c:902 __fput+0x60b/0x9f0 fs/file_table.c:473 task_work_run+0x253/0x310 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [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+0x13f/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f53df58bdca RSP: 002b:00007ffcb537a1a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f53df58bdca RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007ffcb537a1fc R08: 0000000000000000 R09: 00007ffcb5379f07 R10: 0000000000000000 R11: 0000000000000293 R12: 000000000000002e R13: 00000000000927c0 R14: 0000000000040fc1 R15: 00007ffcb537a250 task:syz.7.1059 state:R running task stack:24936 pid:9388 tgid:9388 ppid:6744 task_flags:0x40004c flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 preempt_schedule_irq+0xfe/0x1c0 kernel/sched/core.c:7090 irqentry_exit+0x5e/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+0x0/0x110 kernel/rcu/tree_plugin.h:431 Code: ab 44 89 f9 80 e1 07 80 c1 03 38 c1 7c aa 4c 89 ff e8 14 fc 83 00 eb a0 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 55 41 57 41 56 41 55 41 54 53 49 bc 00 00 00 00 00 fc RSP: 0018:ffffc9000b84f2c0 EFLAGS: 00000286 RAX: 005d268c49d7e100 RBX: ffffc9000b84f400 RCX: 0000000000000002 RDX: dffffc0000000000 RSI: ffffffff8e4fd4cc RDI: ffffffff8ca1b620 RBP: dffffc0000000001 R08: ffffc9000b84f3f0 R09: ffffc9000b84f450 R10: dffffc0000000000 R11: fffff52001709e8c R12: ffffc9000b84f410 R13: dffffc0000000000 R14: ffffc9000b84f400 R15: ffffffff816dfbc8 rcu_read_unlock include/linux/rcupdate.h:873 [inline] class_rcu_destructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0x1aa4/0x23b0 arch/x86/kernel/unwind_orc.c:680 __unwind_start+0x59a/0x740 arch/x86/kernel/unwind_orc.c:758 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe7/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x11a/0x1d0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2389 [inline] slab_free mm/slub.c:4646 [inline] kmem_cache_free+0x197/0x410 mm/slub.c:4748 anon_vma_chain_free mm/rmap.c:147 [inline] unlink_anon_vmas+0x297/0x5f0 mm/rmap.c:421 free_pgtables+0x44e/0x6f0 mm/memory.c:391 exit_mmap+0x5a9/0xde0 mm/mmap.c:1295 __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 __do_sys_exit_group kernel/exit.c:1113 [inline] __se_sys_exit_group kernel/exit.c:1111 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1111 x64_sys_call+0x26c3/0x26d0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f67c438d169 RSP: 002b:00007ffdc1614e38 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f67c438d169 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ffdc1614e9c R08: 00000004c1614f2f R09: 00000000000927c0 R10: 00000000000023c4 R11: 0000000000000246 R12: 000000000000008b R13: 00000000000927c0 R14: 0000000000040e4f R15: 00007ffdc1614ef0 rcu: rcu_preempt kthread starved for 10500 jiffies! g30169 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:26952 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: 63 Comm: kworker/u8:4 Not tainted 6.15.0-rc1-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:rep_nop arch/x86/include/asm/vdso/processor.h:13 [inline] RIP: 0010:cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline] RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0x1baa/0x2d40 kernel/smp.c:885 Code: b6 04 03 84 c0 75 7e 45 8b 65 00 44 89 e6 83 e6 01 31 ff e8 c8 e2 0b 00 41 83 e4 01 4c 8b 64 24 68 75 07 e8 78 de 0b 00 eb 41 90 48 b8 00 00 00 00 00 fc ff df 0f b6 04 03 84 c0 75 11 41 f7 RSP: 0018:ffffc90001557640 EFLAGS: 00000293 RAX: ffffffff81b776cd RBX: 1ffff110170e7e91 RCX: ffff88801cf4bc00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90001557840 R08: ffffffff81b77698 R09: 1ffffffff20bfbee R10: dffffc0000000000 R11: fffffbfff20bfbef R12: ffff8880b863ad08 R13: ffff8880b873f488 R14: ffff8880b863ad00 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888124f96000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007febf1d78ab8 CR3: 000000000eb38000 CR4: 0000000000350ef0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2455 [inline] text_poke_bp_batch+0x354/0xb30 arch/x86/kernel/alternative.c:2665 text_poke_flush arch/x86/kernel/alternative.c:2856 [inline] text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2863 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x136/0x260 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xc0/0x250 mm/kfence/core.c:850 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xac5/0x18e0 kernel/workqueue.c:3319 worker_thread+0x870/0xd50 kernel/workqueue.c:3400 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