Hello! I am seeing the following lockdep splat in next-20210514. It happens at shutdown time in all rcutorture scenarios that enable lockdep. It happens consistently on 2-hour runs, and I am trying it on shorter runs. If it reproduces nicely, I will try bisection. In the meantime, does this ring a bell for anyone? Thanx, Paul ===================================================== WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected 5.13.0-rc1-next-20210514 #1587 Not tainted ----------------------------------------------------- torture_shutdow/112 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: ffffffffaad7ac20 (fs_reclaim){+.+.}-{0:0}, at: fs_reclaim_acquire+0x7f/0xd0 and this task is already holding: ffffa37a02ab4098 (&n->list_lock){-.-.}-{2:2}, at: free_debug_processing+0x3a/0x230 which would create a new lock dependency: (&n->list_lock){-.-.}-{2:2} -> (fs_reclaim){+.+.}-{0:0} but this new dependency connects a HARDIRQ-irq-safe lock: (&n->list_lock){-.-.}-{2:2} ... which became HARDIRQ-irq-safe at: lock_acquire+0xb5/0x3a0 _raw_spin_lock+0x27/0x40 deactivate_slab.isra.90+0x3c2/0x5d0 flush_cpu_slab+0x31/0x50 flush_smp_call_function_queue+0x132/0x1d0 __sysvec_call_function_single+0x3e/0x190 sysvec_call_function_single+0x61/0x80 asm_sysvec_call_function_single+0x12/0x20 default_idle+0xb/0x10 default_idle_call+0x66/0x1e0 do_idle+0x204/0x2a0 cpu_startup_entry+0x14/0x20 secondary_startup_64_no_verify+0xc2/0xcb to a HARDIRQ-irq-unsafe lock: (fs_reclaim){+.+.}-{0:0} ... which became HARDIRQ-irq-unsafe at: ... lock_acquire+0xb5/0x3a0 fs_reclaim_acquire+0x9f/0xd0 kmem_cache_alloc_node_trace+0x2f/0x230 alloc_worker+0x18/0x50 init_rescuer.part.33+0xf/0x90 workqueue_init+0x1fb/0x2db kernel_init_freeable+0x10c/0x26f kernel_init+0x5/0xfe ret_from_fork+0x22/0x30 other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); local_irq_disable(); lock(&n->list_lock); lock(fs_reclaim); <Interrupt> lock(&n->list_lock); *** DEADLOCK *** 1 lock held by torture_shutdow/112: #0: ffffa37a02ab4098 (&n->list_lock){-.-.}-{2:2}, at: free_debug_processing+0x3a/0x230 the dependencies between HARDIRQ-irq-safe lock and the holding lock: -> (&n->list_lock){-.-.}-{2:2} { IN-HARDIRQ-W at: lock_acquire+0xb5/0x3a0 _raw_spin_lock+0x27/0x40 deactivate_slab.isra.90+0x3c2/0x5d0 flush_cpu_slab+0x31/0x50 flush_smp_call_function_queue+0x132/0x1d0 __sysvec_call_function_single+0x3e/0x190 sysvec_call_function_single+0x61/0x80 asm_sysvec_call_function_single+0x12/0x20 default_idle+0xb/0x10 default_idle_call+0x66/0x1e0 do_idle+0x204/0x2a0 cpu_startup_entry+0x14/0x20 secondary_startup_64_no_verify+0xc2/0xcb IN-SOFTIRQ-W at: lock_acquire+0xb5/0x3a0 _raw_spin_lock_irqsave+0x30/0x50 __slab_free+0xc8/0x4a0 kmem_cache_free+0x2a8/0x310 rcu_do_batch+0x18e/0x4d0 rcu_core+0x2c7/0x470 __do_softirq+0xca/0x409 irq_exit_rcu+0xa9/0xb0 sysvec_apic_timer_interrupt+0x66/0x80 asm_sysvec_apic_timer_interrupt+0x12/0x20 default_idle+0xb/0x10 default_idle_call+0x66/0x1e0 do_idle+0x204/0x2a0 cpu_startup_entry+0x14/0x20 start_kernel+0x6ab/0x6d2 secondary_startup_64_no_verify+0xc2/0xcb INITIAL USE at: lock_acquire+0xb5/0x3a0 _raw_spin_lock+0x27/0x40 get_partial_node.isra.92.part.93+0x47/0x300 ___slab_alloc+0x2a1/0x6e0 kmem_cache_alloc_node+0x1bc/0x230 __kmem_cache_create+0x1b3/0x430 create_boot_cache+0x70/0x93 kmem_cache_init+0xd9/0x15f start_kernel+0x3e6/0x6d2 secondary_startup_64_no_verify+0xc2/0xcb } ... key at: [<ffffffffabfa6370>] __key.50785+0x0/0x10 ... acquired at: lock_acquire+0xb5/0x3a0 fs_reclaim_acquire+0x9f/0xd0 __alloc_pages+0xed/0x330 stack_depot_save+0x3a1/0x470 save_stack_depot_trace.constprop.100+0x3b/0x60 set_track+0x27/0x80 free_debug_processing+0x169/0x230 __slab_free+0x262/0x4a0 kmem_cache_free+0x2a8/0x310 rcu_torture_cleanup.cold.34+0x186/0x41d torture_shutdown+0x101/0x1f0 kthread+0x122/0x140 ret_from_fork+0x22/0x30 the dependencies between the lock to be acquired and HARDIRQ-irq-unsafe lock: -> (fs_reclaim){+.+.}-{0:0} { HARDIRQ-ON-W at: lock_acquire+0xb5/0x3a0 fs_reclaim_acquire+0x9f/0xd0 kmem_cache_alloc_node_trace+0x2f/0x230 alloc_worker+0x18/0x50 init_rescuer.part.33+0xf/0x90 workqueue_init+0x1fb/0x2db kernel_init_freeable+0x10c/0x26f kernel_init+0x5/0xfe ret_from_fork+0x22/0x30 SOFTIRQ-ON-W at: lock_acquire+0xb5/0x3a0 fs_reclaim_acquire+0x9f/0xd0 kmem_cache_alloc_node_trace+0x2f/0x230 alloc_worker+0x18/0x50 init_rescuer.part.33+0xf/0x90 workqueue_init+0x1fb/0x2db kernel_init_freeable+0x10c/0x26f kernel_init+0x5/0xfe ret_from_fork+0x22/0x30 INITIAL USE at: lock_acquire+0xb5/0x3a0 fs_reclaim_acquire+0x9f/0xd0 kmem_cache_alloc_node_trace+0x2f/0x230 alloc_worker+0x18/0x50 init_rescuer.part.33+0xf/0x90 workqueue_init+0x1fb/0x2db kernel_init_freeable+0x10c/0x26f kernel_init+0x5/0xfe ret_from_fork+0x22/0x30 } ... key at: [<ffffffffaad7ac20>] __fs_reclaim_map+0x0/0x28 ... acquired at: lock_acquire+0xb5/0x3a0 fs_reclaim_acquire+0x9f/0xd0 __alloc_pages+0xed/0x330 stack_depot_save+0x3a1/0x470 save_stack_depot_trace.constprop.100+0x3b/0x60 set_track+0x27/0x80 free_debug_processing+0x169/0x230 __slab_free+0x262/0x4a0 kmem_cache_free+0x2a8/0x310 rcu_torture_cleanup.cold.34+0x186/0x41d torture_shutdown+0x101/0x1f0 kthread+0x122/0x140 ret_from_fork+0x22/0x30 stack backtrace: CPU: 0 PID: 112 Comm: torture_shutdow Not tainted 5.13.0-rc1-next-20210514 #1587 Hardware name: Red Hat KVM/RHEL-AV, BIOS 1.13.0-2.module_el8.4.0+547+a85d02ba 04/01/2014 Call Trace: dump_stack_lvl+0x6a/0x88 check_irq_usage.cold.80+0x2cd/0x2d2 ? trace_event_raw_event_lock+0xf0/0xf0 ? check_path.constprop.61+0x24/0x40 ? check_noncircular+0x7e/0x110 ? __lock_acquire+0x13a0/0x23c0 __lock_acquire+0x13a0/0x23c0 lock_acquire+0xb5/0x3a0 ? fs_reclaim_acquire+0x7f/0xd0 ? __lock_acquire+0xa8e/0x23c0 ? get_stack_info_noinstr+0x12/0xe0 ? unwind_next_frame+0x4a3/0x6a0 fs_reclaim_acquire+0x9f/0xd0 ? fs_reclaim_acquire+0x7f/0xd0 __alloc_pages+0xed/0x330 stack_depot_save+0x3a1/0x470 ? rcu_torture_cleanup.cold.34+0x186/0x41d save_stack_depot_trace.constprop.100+0x3b/0x60 ? kmem_cache_free+0x2a8/0x310 ? rcu_torture_cleanup.cold.34+0x186/0x41d ? torture_shutdown+0x101/0x1f0 ? kthread+0x122/0x140 ? ret_from_fork+0x22/0x30 set_track+0x27/0x80 free_debug_processing+0x169/0x230 ? rcu_torture_cleanup.cold.34+0x186/0x41d ? rcu_torture_cleanup.cold.34+0x186/0x41d __slab_free+0x262/0x4a0 ? vprintk_emit+0x89/0x270 ? torture_onoff+0x260/0x260 ? rcu_torture_cleanup.cold.34+0x186/0x41d kmem_cache_free+0x2a8/0x310 ? torture_onoff+0x260/0x260 rcu_torture_cleanup.cold.34+0x186/0x41d ? wait_woken+0x80/0x80 ? torture_onoff+0x260/0x260 torture_shutdown+0x101/0x1f0 kthread+0x122/0x140 ? kthread_park+0x80/0x80 ret_from_fork+0x22/0x30