Increase LOCKDEP_CIRCULAR_QUEUE_BITS to avoid this warning: ------------[ cut here ]------------ lockdep bfs error:-1 WARNING: CPU: 0 PID: 5169 at kernel/locking/lockdep.c:2059 print_bfs_bug+0x29/0x50 kernel/locking/lockdep.c:2059 Modules linked in: CPU: 0 UID: 0 PID: 5169 Comm: udevd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:print_bfs_bug+0x29/0x50 kernel/locking/lockdep.c:2059 Code: 90 55 53 89 fb e8 a7 d4 d9 02 89 c5 e8 00 a6 ff ff 85 ed 74 19 83 fb ff 74 1c 90 48 c7 c7 f9 ff d9 8c 89 de e8 c8 d9 e6 ff 90 <0f> 0b 90 90 5b 5d c3 cc cc cc cc cc 48 c7 c7 ed 42 eb 8c e8 df 10 RSP: 0018:ffffc90004067080 EFLAGS: 00010046 RAX: 5d2e00692dd19100 RBX: 00000000ffffffff RCX: ffff888037870000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffed101710487b R12: ffffffff955bc2b8 R13: ffffffff955bc408 R14: ffff888037870c50 R15: 0000000000000018 FS: 00007f820e280880(0000) GS:ffff888126dfc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f037c29bf98 CR3: 00000000363bc000 CR4: 00000000003526f0 Call Trace: check_irq_usage kernel/locking/lockdep.c:-1 [inline] check_prev_add kernel/locking/lockdep.c:3169 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0x1a4b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162 remove_entity_load_avg kernel/sched/fair.c:4788 [inline] migrate_task_rq_fair+0xab/0x610 kernel/sched/fair.c:8648 set_task_cpu+0x337/0x990 kernel/sched/core.c:3330 try_to_wake_up+0x5c9/0x12b0 kernel/sched/core.c:4290 swake_up_locked kernel/sched/swait.c:30 [inline] swake_up_one+0x70/0x140 kernel/sched/swait.c:53 rcu_report_unblock_qs_rnp kernel/rcu/tree.c:2414 [inline] rcu_preempt_deferred_qs_irqrestore+0xa11/0xce0 kernel/rcu/tree_plugin.h:571 rcu_read_unlock_special+0x35b/0x470 kernel/rcu/tree_plugin.h:770 __rcu_read_unlock+0x84/0xe0 kernel/rcu/tree_plugin.h:438 rcu_read_unlock include/linux/rcupdate.h:899 [inline] rt_spin_unlock+0x161/0x200 kernel/locking/spinlock_rt.c:82 spin_unlock_irqrestore include/linux/spinlock_rt.h:122 [inline] get_partial_node+0x3f0/0x420 mm/slub.c:3530 get_partial mm/slub.c:3610 [inline] ___slab_alloc+0x9f3/0x13f0 mm/slub.c:4626 __slab_alloc+0xc6/0x1f0 mm/slub.c:4770 __slab_alloc_node mm/slub.c:4846 [inline] slab_alloc_node mm/slub.c:5268 [inline] kmem_cache_alloc_node_noprof+0x1ac/0x6e0 mm/slub.c:5332 kmalloc_reserve+0xbd/0x290 net/core/skbuff.c:579 __alloc_skb+0x142/0x2d0 net/core/skbuff.c:670 alloc_skb include/linux/skbuff.h:1383 [inline] alloc_uevent_skb+0x7d/0x230 lib/kobject_uevent.c:289 uevent_net_broadcast_untagged lib/kobject_uevent.c:326 [inline] kobject_uevent_net_broadcast+0x2fd/0x560 lib/kobject_uevent.c:410 kobject_uevent_env+0x55e/0x8c0 lib/kobject_uevent.c:608 kobject_synth_uevent+0x527/0xb00 lib/kobject_uevent.c:207 uevent_store+0x26/0x70 drivers/base/core.c:2773 kernfs_fop_write_iter+0x3b0/0x540 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5d5/0xb40 fs/read_write.c:686 ksys_write+0x14b/0x260 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f820e36e407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffd61003340 EFLAGS: 00000202 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f820e280880 RCX: 00007f820e36e407 RDX: 0000000000000007 RSI: 000056166dedaa00 RDI: 000000000000000c RBP: 000056166dedaa00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000007 R13: 000056166ded87a0 R14: 00007f820e4b6ea0 R15: 00007ffd61003680