rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=36b4/1/0x4000000000000000 softirq=214067/214071 fqs=2 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P27392/1:b..l rcu: (detected by 0, t=10502 jiffies, g=191793, q=354 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 27387 Comm: syz.7.4952 Not tainted 6.16.0-rc5-next-20250711-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:__this_cpu_preempt_check+0xe/0x20 lib/smp_processor_id.c:66 Code: 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 89 fe 48 c7 c7 c0 47 e3 8b bd fe ff ff cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 RSP: 0018:ffffc90000a08b70 EFLAGS: 00000046 RAX: 4d4df099ab2b819a RBX: 0000000000000002 RCX: 2bd34f9158a9bf00 RDX: 0000000000000002 RSI: ffffffff8dba77be RDI: ffffffff8be347c0 RBP: ffff88802477c740 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff5200014116c R12: 0000000000000002 R13: 0000000000000002 R14: ffffffff99cfc110 R15: ffff88802477bc00 FS: 0000000000000000(0000) GS:ffff888125cc6000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0619bb7bac CR3: 00000000352ea000 CR4: 00000000003526f0 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:473 [inline] lock_release+0x27a/0x3e0 kernel/locking/lockdep.c:5894 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline] _raw_spin_unlock_irqrestore+0x70/0x110 kernel/locking/spinlock.c:194 debug_object_activate+0x2e2/0x420 lib/debugobjects.c:836 debug_hrtimer_activate kernel/time/hrtimer.c:445 [inline] debug_activate kernel/time/hrtimer.c:484 [inline] enqueue_hrtimer+0x30/0x3a0 kernel/time/hrtimer.c:1088 __run_hrtimer kernel/time/hrtimer.c:1778 [inline] __hrtimer_run_queues+0x656/0xc60 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+0x108/0x410 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:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:210 Code: 89 fb e8 23 00 00 00 48 8b 3d 04 5d fe 0b 48 89 de 5b e9 23 e5 59 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 08 a0 a5 92 65 8b 15 88 e8 RSP: 0018:ffffc90004457068 EFLAGS: 00000202 RAX: ffffffff822f9912 RBX: ffff88801b580000 RCX: 0000000000000000 RDX: ffff88802477bc00 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff822fa2fa R10: dffffc0000000000 R11: ffffed100b02aba2 R12: 000000000004d392 R13: dffffc0000000000 R14: ffff88813fffa530 R15: 0000000000001000 lookup_page_ext mm/page_ext.c:254 [inline] page_ext_lookup+0xfb/0x180 mm/page_ext.c:509 page_ext_iter_begin include/linux/page_ext.h:132 [inline] __page_table_check_zero+0x18f/0x530 mm/page_table_check.c:139 page_table_check_free include/linux/page_table_check.h:43 [inline] free_pages_prepare mm/page_alloc.c:1396 [inline] free_unref_folios+0xdd1/0x1520 mm/page_alloc.c:2952 folios_put_refs+0x559/0x640 mm/swap.c:992 folio_batch_release include/linux/pagevec.h:101 [inline] shmem_undo_range+0x49e/0x14b0 mm/shmem.c:1125 shmem_truncate_range mm/shmem.c:1237 [inline] shmem_evict_inode+0x272/0xa70 mm/shmem.c:1365 evict+0x504/0x9c0 fs/inode.c:810 __dentry_kill+0x209/0x660 fs/dcache.c:669 dput+0x19f/0x2b0 fs/dcache.c:911 __fput+0x68e/0xa70 fs/file_table.c:476 task_work_run+0x1d4/0x260 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x6b5/0x2300 kernel/exit.c:959 do_group_exit+0x21c/0x2d0 kernel/exit.c:1100 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:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:208 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fca82b8e929 Code: Unable to access opcode bytes at 0x7fca82b8e8ff. RSP: 002b:00007fca809d5038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: 0000000000000000 RBX: 00007fca82db6080 RCX: 00007fca82b8e929 RDX: 000000000000006e RSI: 000020000057eff8 RDI: 0000000000000003 RBP: 00007fca82c10b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fca82db6080 R15: 00007ffe7fba3548 task:syz.0.4953 state:R running task stack:25128 pid:27392 tgid:27388 ppid:22031 task_flags:0x400040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5314 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6697 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7020 irqentry_exit+0x6f/0x90 kernel/entry/common.c:196 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707 RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline] RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:124 [inline] RIP: 0010:lock_release+0x78/0x3e0 kernel/locking/lockdep.c:5884 Code: 0d f6 05 99 e6 ef 0d 01 0f 84 ad 02 00 00 83 3d 8d 37 06 0e 00 0f 84 44 02 00 00 65 8b 05 50 2b 08 11 85 c0 0f 85 35 02 00 00 <65> 4c 8b 3c 25 08 a0 a5 92 41 83 bf ec 0a 00 00 00 0f 85 1e 02 00 RSP: 0018:ffffc9000455f850 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffc9000455f901 RCX: b2d045f4bcf5d500 RDX: ffffffff90426901 RSI: ffffffff8be347a0 RDI: ffffffff8be34760 RBP: dffffc0000000000 R08: ffffc9000455f9e7 R09: 0000000000000000 R10: ffffc9000455f9d8 R11: fffff520008abf3d R12: ffffc9000455fef0 R13: ffffffff81729ea5 R14: ffffffff8e13c5a0 R15: ffffffff81729ea5 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+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2417 [inline] slab_free mm/slub.c:4680 [inline] kmem_cache_free+0x18f/0x400 mm/slub.c:4782 file_free fs/file_table.c:71 [inline] __fput+0x6c2/0xa70 fs/file_table.c:481 fput_close_sync+0x119/0x200 fs/file_table.c:573 __do_sys_close fs/open.c:1587 [inline] __se_sys_close fs/open.c:1572 [inline] __x64_sys_close+0x7f/0x110 fs/open.c:1572 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: 0033:0x7feb6098d58a RSP: 002b:00007feb5e7f5e00 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 0000000000000458 RCX: 00007feb6098d58a RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000001e RBP: 000000000000000c R08: 00000000ffffffff R09: 0000000000000000 R10: 0000000000000022 R11: 0000000000000293 R12: 000000000000001e R13: 00007feb5e7f5ef0 R14: 00007feb5e7f5eb0 R15: ffffffffffffffff rcu: rcu_preempt kthread starved for 10498 jiffies! g191793 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:5314 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6697 __schedule_loop kernel/sched/core.c:6775 [inline] schedule+0x165/0x360 kernel/sched/core.c:6790 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2062 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2264 kthread+0x711/0x8a0 kernel/kthread.c:463 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: 27393 Comm: syz.0.4953 Not tainted 6.16.0-rc5-next-20250711-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+0xd33/0x12d0 kernel/smp.c:869 Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 a6 6a 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 51 66 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 35 66 RSP: 0018:ffffc900038ff560 EFLAGS: 00000293 RAX: ffffffff81b4515b RBX: 1ffff110170e7f69 RCX: ffff888060269e00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900038ff6e0 R08: ffffffff8fa3bb37 R09: 1ffffffff1f47766 R10: dffffc0000000000 R11: fffffbfff1f47767 R12: ffff8880b873fb48 R13: dffffc0000000000 R14: ffff8880b863b200 R15: 0000000000000001 FS: 00007feb5e7d56c0(0000) GS:ffff888125bc6000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f98fdf743e0 CR3: 000000003d638000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1036 __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 vms_clear_ptes+0x42c/0x540 mm/vma.c:1235 vms_complete_munmap_vmas+0x206/0x8a0 mm/vma.c:1277 do_vmi_align_munmap+0x358/0x420 mm/vma.c:1536 do_vmi_munmap+0x253/0x2e0 mm/vma.c:1584 __vm_munmap+0x23b/0x3d0 mm/vma.c:3157 __do_sys_munmap mm/mmap.c:1083 [inline] __se_sys_munmap mm/mmap.c:1080 [inline] __x64_sys_munmap+0x60/0x70 mm/mmap.c:1080 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: 0033:0x7feb6098e9b7 Code: 00 00 00 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 0b 00 00 00 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:00007feb5e7d4e18 EFLAGS: 00000246 ORIG_RAX: 000000000000000b RAX: ffffffffffffffda RBX: 0000000000080000 RCX: 00007feb6098e9b7 RDX: 0000000000000000 RSI: 0000000008400000 RDI: 00007feb56200000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000591 R10: 0000200000000b82 R11: 0000000000000246 R12: 000000000000001f R13: 00007feb5e7d4ef0 R14: 00007feb5e7d4eb0 R15: 00007feb56200000