rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=24ac/1/0x4000000000000000 softirq=25625/25629 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P2996/1:b..l P7073/1:b..l rcu: (detected by 1, t=10505 jiffies, g=19893, q=820 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 7072 Comm: syz.1.291 Not tainted 6.16.0-rc5-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:__lock_acquire+0xaf6/0xd20 kernel/locking/lockdep.c:-1 Code: 4c 89 bb e0 0a 00 00 8b 83 e8 0a 00 00 ff c0 89 83 e8 0a 00 00 83 f8 30 0f 83 64 01 00 00 3b 05 98 6b 06 12 0f 87 c9 01 00 00 <41> bf 01 00 00 00 e9 a7 01 00 00 48 89 fb e8 e7 8f 03 00 48 c7 c7 RSP: 0018:ffffc90000007ab0 EFLAGS: 00000087 RAX: 0000000000000005 RBX: ffff88807b2f8000 RCX: 76cccc55d6b76800 RDX: 0000000000000000 RSI: ffff88807b2f8b90 RDI: ffff88807b2f8000 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff84c0c66b R10: ffffc90000007ca0 R11: fffff52000000f96 R12: 00000000b2b20f67 R13: ffff88807b2f8af0 R14: ffff88807b2f8b90 R15: a26fb770857742d4 FS: 00007f606a6936c0(0000) GS:ffff888125c51000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f606a692f98 CR3: 000000002999e000 CR4: 00000000003526f0 DR0: 0000000000000005 DR1: 0000000000000047 DR2: 0000000000000007 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162 debug_object_activate+0xbb/0x420 lib/debugobjects.c:818 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+0x10b/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:lock_is_held_type+0x137/0x190 kernel/locking/lockdep.c:5948 Code: 01 75 44 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 4c 41 f7 c4 00 02 00 00 74 01 fb 65 48 8b 05 29 f3 34 07 <48> 3b 44 24 08 75 43 89 d8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffffc900046af3f8 EFLAGS: 00000206 RAX: 76cccc55d6b76800 RBX: 0000000000000001 RCX: 76cccc55d6b76800 RDX: ffff88807b2f8000 RSI: ffffffff8db707c4 RDI: ffffffff8be1c200 RBP: 00000000ffffffff R08: ffff88807b2f8000 R09: 0000000000000002 R10: 0000000000000003 R11: 0000000000000002 R12: 0000000000000246 R13: ffff88807b2f8000 R14: ffffffff8e13ee60 R15: 0000000000000001 xa_head include/linux/xarray.h:1210 [inline] xas_start+0x295/0x770 lib/xarray.c:191 xas_load+0x2c/0x5b0 lib/xarray.c:239 xas_find+0x157/0x990 lib/xarray.c:1406 next_uptodate_folio+0x32/0x5d0 mm/filemap.c:3562 filemap_map_pages+0x21f/0x1740 mm/filemap.c:3714 do_fault_around mm/memory.c:5548 [inline] do_read_fault mm/memory.c:5581 [inline] do_fault mm/memory.c:5724 [inline] do_pte_missing mm/memory.c:4251 [inline] handle_pte_fault mm/memory.c:6069 [inline] __handle_mm_fault+0x368a/0x5620 mm/memory.c:6212 handle_mm_fault+0x2d5/0x7f0 mm/memory.c:6381 faultin_page mm/gup.c:1186 [inline] __get_user_pages+0x1af4/0x30b0 mm/gup.c:1488 populate_vma_page_range+0x26b/0x340 mm/gup.c:1926 __mm_populate+0x24c/0x380 mm/gup.c:2029 mm_populate include/linux/mm.h:3348 [inline] vm_mmap_pgoff+0x3f0/0x4c0 mm/util.c:584 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: 0033:0x7f606978e929 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 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:00007f606a693038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f60699b6080 RCX: 00007f606978e929 RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007f6069810b39 R08: 0000000000000004 R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f60699b6080 R15: 00007fffb36acac8 task:syz.3.292 state:R running task stack:25464 pid:7073 tgid:7069 ppid:5842 task_flags:0x400140 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5401 [inline] __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6790 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6970 preempt_schedule+0xae/0xc0 kernel/sched/core.c:6994 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] follow_page_pte+0x1dd/0x14b0 mm/gup.c:940 follow_pmd_mask mm/gup.c:971 [inline] follow_pud_mask mm/gup.c:1023 [inline] follow_p4d_mask mm/gup.c:1040 [inline] follow_page_mask mm/gup.c:1083 [inline] __get_user_pages+0xbad/0x30b0 mm/gup.c:1486 __get_user_pages_locked mm/gup.c:1754 [inline] faultin_page_range+0x257/0x890 mm/gup.c:1978 madvise_populate mm/madvise.c:974 [inline] madvise_do_behavior+0x232/0x2e70 mm/madvise.c:1731 do_madvise+0x174/0x220 mm/madvise.c:1826 __do_sys_madvise mm/madvise.c:1835 [inline] __se_sys_madvise mm/madvise.c:1833 [inline] __x64_sys_madvise+0xa7/0xc0 mm/madvise.c:1833 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: 0033:0x7f231638e929 RSP: 002b:00007f2317289038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007f23165b6080 RCX: 00007f231638e929 RDX: 0000000000000016 RSI: 0000000000c00000 RDI: 0000200000000000 RBP: 00007f2316410b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f23165b6080 R15: 00007ffe205fbde8 task:kworker/u8:10 state:R running task stack:23360 pid:2996 tgid:2996 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: iou_exit io_ring_exit_work Call Trace: context_switch kernel/sched/core.c:5401 [inline] __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6790 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7113 irqentry_exit+0x6f/0x90 kernel/entry/common.c:307 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5875 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 ab c1 fe 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc9000be971f8 EFLAGS: 00000206 RAX: ccfa5d4cbdf5b300 RBX: 0000000000000000 RCX: ccfa5d4cbdf5b300 RDX: 0000000000000000 RSI: ffffffff8db707c4 RDI: ffffffff8be1c200 RBP: ffffffff81729af5 R08: 0000000000000000 R09: ffffffff81729af5 R10: ffffc9000be973b8 R11: ffffffff81acf220 R12: 0000000000000002 R13: ffffffff8e13ee60 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548 __call_rcu_common kernel/rcu/tree.c:3094 [inline] call_rcu+0x157/0x9c0 kernel/rcu/tree.c:3214 slab_free_hook mm/slub.c:2345 [inline] slab_free mm/slub.c:4643 [inline] kmem_cache_free+0x309/0x400 mm/slub.c:4745 __io_req_caches_free+0x8f/0x140 io_uring/io_uring.c:2710 io_req_caches_free+0x21/0x30 io_uring/io_uring.c:2722 io_ring_exit_work+0x415/0x930 io_uring/io_uring.c:2920 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread starved for 10505 jiffies! g19893 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:27320 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5401 [inline] __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6790 __schedule_loop kernel/sched/core.c:6868 [inline] schedule+0x165/0x360 kernel/sched/core.c:6883 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/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: 1 UID: 0 PID: 1093 Comm: kworker/u8:5 Not tainted 6.16.0-rc5-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0xf69/0x12d0 kernel/smp.c:885 Code: 00 45 8b 2f 44 89 ee 83 e6 01 31 ff e8 c0 78 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 6b 74 0b 00 eb 37 f3 90 <43> 0f b6 04 2c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 50 74 0b RSP: 0018:ffffc9000401f6a0 EFLAGS: 00000293 RAX: ffffffff81b4b090 RBX: ffff8880b873b040 RCX: ffff888026915a00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000401f800 R08: ffffffff8fa0bbf7 R09: 1ffffffff1f4177e R10: dffffc0000000000 R11: fffffbfff1f4177f R12: 1ffff110170c835d R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8641ae8 FS: 0000000000000000(0000) GS:ffff888125d51000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c2e19d3 CR3: 000000000df38000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2691 [inline] smp_text_poke_batch_finish+0x5e0/0x1100 arch/x86/kernel/alternative.c:2901 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x128/0x250 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:850 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245