============================================ WARNING: possible recursive locking detected 6.1.80-syzkaller #0 Not tainted -------------------------------------------- syz-executor.1/21193 is trying to acquire lock: ffff8880b9828358 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x120/0x260 kernel/time/timer.c:999 but task is already holding lock: ffff8880b9928358 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x120/0x260 kernel/time/timer.c:999 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&base->lock); lock(&base->lock); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by syz-executor.1/21193: #0: ffffffff8e288cd0 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x37b/0x5d0 net/core/net_namespace.c:474 #1: ffff8880b9928358 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x120/0x260 kernel/time/timer.c:999 stack backtrace: CPU: 1 PID: 21193 Comm: syz-executor.1 Not tainted 6.1.80-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2983 [inline] check_deadlock kernel/locking/lockdep.c:3026 [inline] validate_chain+0x4711/0x5950 kernel/locking/lockdep.c:3812 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 lock_timer_base+0x120/0x260 kernel/time/timer.c:999 __mod_timer+0x1cb/0xee0 kernel/time/timer.c:1072 queue_delayed_work_on+0x156/0x250 kernel/workqueue.c:1704 free_pages_prepare mm/page_alloc.c:1446 [inline] free_pcp_prepare mm/page_alloc.c:1490 [inline] free_unref_page_prepare+0x319/0x1120 mm/page_alloc.c:3358 free_unref_page+0x33/0x3e0 mm/page_alloc.c:3453 __stack_depot_save+0x409/0x470 lib/stackdepot.c:506 kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x60/0x70 mm/kasan/common.c:52 __kasan_slab_alloc+0x65/0x70 mm/kasan/common.c:328 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x52/0x3a0 mm/slab.h:737 slab_alloc_node mm/slub.c:3398 [inline] slab_alloc mm/slub.c:3406 [inline] __kmem_cache_alloc_lru mm/slub.c:3413 [inline] kmem_cache_alloc+0x10c/0x2d0 mm/slub.c:3422 kmem_cache_zalloc include/linux/slab.h:682 [inline] fill_pool lib/debugobjects.c:168 [inline] debug_objects_fill_pool+0x68f/0xa10 lib/debugobjects.c:606 debug_object_activate+0x32/0x4e0 lib/debugobjects.c:693 debug_timer_activate kernel/time/timer.c:782 [inline] __mod_timer+0x7bf/0xee0 kernel/time/timer.c:1103 queue_delayed_work_on+0x156/0x250 kernel/workqueue.c:1704 queue_delayed_work include/linux/workqueue.h:527 [inline] schedule_delayed_work include/linux/workqueue.h:679 [inline] ovs_init_net+0x234/0x240 net/openvswitch/datapath.c:2611 ops_init+0x356/0x600 net/core/net_namespace.c:135 setup_net+0x4b5/0xb90 net/core/net_namespace.c:332 copy_net_ns+0x395/0x5d0 net/core/net_namespace.c:478 create_new_namespaces+0x425/0x7a0 kernel/nsproxy.c:110 copy_namespaces+0x397/0x3f0 kernel/nsproxy.c:178 copy_process+0x1ab8/0x4060 kernel/fork.c:2270 kernel_clone+0x222/0x920 kernel/fork.c:2682 __do_sys_clone3 kernel/fork.c:2981 [inline] __se_sys_clone3+0x373/0x410 kernel/fork.c:2965 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f91e8e7dda9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f91e9b65f98 EFLAGS: 00000246 ORIG_RAX: 00000000000001b3 RAX: ffffffffffffffda RBX: 0000000000000058 RCX: 00007f91e8e7dda9 RDX: 00007f91e9b65fb0 RSI: 0000000000000058 RDI: 00007f91e9b65fb0 RBP: 00007f91e8eca47a R08: 0000000000000000 R09: 0000000000000058 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007f91e8fac120 R15: 00007ffe4179f1e8