syzbot

======================================================
WARNING: possible circular locking dependency detected
6.9.0-rc6-syzkaller-00113-g49a73b1652c5 #0 Not tainted
------------------------------------------------------
syz-executor.5/6143 is trying to acquire lock:
ffffffff8ea4a3e8 (pool_lock#2){-.-.}-{2:2}, at: stack_depot_save_flags+0x240/0x830 lib/stackdepot.c:640

but task is already holding lock:
ffff88805b5eb1f8 (&trie->lock){-.-.}-{2:2}, at: trie_update_elem+0xcb/0xc10 kernel/bpf/lpm_trie.c:324

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&trie->lock){-.-.}-{2:2}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
       trie_delete_elem+0x96/0x6a0 kernel/bpf/lpm_trie.c:451
       0xffffffffa0000866
       bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
       __bpf_prog_run include/linux/filter.h:657 [inline]
       bpf_prog_run include/linux/filter.h:664 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
       bpf_trace_run2+0x206/0x420 kernel/trace/bpf_trace.c:2420
       trace_contention_end+0x114/0x140 include/trace/events/lock.h:122
       __pv_queued_spin_lock_slowpath+0x939/0xc60 kernel/locking/qspinlock.c:560
       pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline]
       queued_spin_lock_slowpath+0x42/0x50 arch/x86/include/asm/qspinlock.h:51
       queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
       do_raw_spin_lock+0x272/0x370 kernel/locking/spinlock_debug.c:116
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
       _raw_spin_lock_irqsave+0xe1/0x120 kernel/locking/spinlock.c:162
       stack_depot_save_flags+0x240/0x830 lib/stackdepot.c:640
       kasan_save_stack mm/kasan/common.c:48 [inline]
       kasan_save_track+0x51/0x80 mm/kasan/common.c:68
       unpoison_slab_object mm/kasan/common.c:312 [inline]
       __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338
       kasan_slab_alloc include/linux/kasan.h:201 [inline]
       slab_post_alloc_hook mm/slub.c:3798 [inline]
       slab_alloc_node mm/slub.c:3845 [inline]
       kmem_cache_alloc+0x174/0x340 mm/slub.c:3852
       kmem_cache_zalloc include/linux/slab.h:739 [inline]
       fill_pool lib/debugobjects.c:168 [inline]
       debug_objects_fill_pool+0x79e/0x9b0 lib/debugobjects.c:615
       debug_object_activate+0x135/0x510 lib/debugobjects.c:704
       debug_rcu_head_queue kernel/rcu/rcu.h:227 [inline]
       __call_rcu_common kernel/rcu/tree.c:2719 [inline]
       call_rcu+0x97/0xa70 kernel/rcu/tree.c:2838
       kernfs_put+0x1dc/0x370 fs/kernfs/dir.c:578
       kernfs_remove_by_name_ns+0xe4/0x160 fs/kernfs/dir.c:1695
       kernfs_remove_by_name include/linux/kernfs.h:625 [inline]
       remove_files fs/sysfs/group.c:28 [inline]
       sysfs_remove_group+0xfe/0x2c0 fs/sysfs/group.c:319
       sysfs_remove_groups+0x54/0xb0 fs/sysfs/group.c:343
       __kobject_del+0x84/0x310 lib/kobject.c:595
       kobject_cleanup lib/kobject.c:680 [inline]
       kobject_release lib/kobject.c:720 [inline]
       kref_put include/linux/kref.h:65 [inline]
       kobject_put+0x245/0x480 lib/kobject.c:737
       nilfs_sysfs_delete_checkpoints_group fs/nilfs2/sysfs.c:348 [inline]
       nilfs_sysfs_delete_device_group+0x63/0xf0 fs/nilfs2/sysfs.c:1041
       nilfs_put_super+0xaf/0x160 fs/nilfs2/super.c:507
       generic_shutdown_super+0x138/0x2d0 fs/super.c:641
       kill_block_super+0x44/0x90 fs/super.c:1675
       deactivate_locked_super+0xc6/0x130 fs/super.c:472
       cleanup_mnt+0x426/0x4c0 fs/namespace.c:1267
       task_work_run+0x251/0x310 kernel/task_work.c:180
       resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
       exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
       exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
       __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
       syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218
       do_syscall_64+0x102/0x240 arch/x86/entry/common.c:89
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (pool_lock#2){-.-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
       __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
       stack_depot_save_flags+0x240/0x830 lib/stackdepot.c:640
       kasan_save_stack mm/kasan/common.c:48 [inline]
       kasan_save_track+0x51/0x80 mm/kasan/common.c:68
       poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
       __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
       kasan_kmalloc include/linux/kasan.h:211 [inline]
       __do_kmalloc_node mm/slub.c:3966 [inline]
       __kmalloc_node+0x253/0x4e0 mm/slub.c:3973
       kmalloc_node include/linux/slab.h:648 [inline]
       bpf_map_kmalloc_node+0xd3/0x1c0 kernel/bpf/syscall.c:422
       lpm_trie_node_alloc kernel/bpf/lpm_trie.c:291 [inline]
       trie_update_elem+0x1d3/0xc10 kernel/bpf/lpm_trie.c:333
       bpf_map_update_value+0x4d5/0x540 kernel/bpf/syscall.c:203
       map_update_elem+0x53a/0x6f0 kernel/bpf/syscall.c:1641
       __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5648
       __do_sys_bpf kernel/bpf/syscall.c:5767 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:5765 [inline]
       __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5765
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&trie->lock);
                               lock(pool_lock#2);
                               lock(&trie->lock);
  lock(pool_lock#2);

 *** DEADLOCK ***

2 locks held by syz-executor.5/6143:
 #0: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #0: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #0: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: bpf_map_update_value+0x3c4/0x540 kernel/bpf/syscall.c:202
 #1: ffff88805b5eb1f8 (&trie->lock){-.-.}-{2:2}, at: trie_update_elem+0xcb/0xc10 kernel/bpf/lpm_trie.c:324

stack backtrace:
CPU: 0 PID: 6143 Comm: syz-executor.5 Not tainted 6.9.0-rc6-syzkaller-00113-g49a73b1652c5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
 stack_depot_save_flags+0x240/0x830 lib/stackdepot.c:640
 kasan_save_stack mm/kasan/common.c:48 [inline]
 kasan_save_track+0x51/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slub.c:3966 [inline]
 __kmalloc_node+0x253/0x4e0 mm/slub.c:3973
 kmalloc_node include/linux/slab.h:648 [inline]
 bpf_map_kmalloc_node+0xd3/0x1c0 kernel/bpf/syscall.c:422
 lpm_trie_node_alloc kernel/bpf/lpm_trie.c:291 [inline]
 trie_update_elem+0x1d3/0xc10 kernel/bpf/lpm_trie.c:333
 bpf_map_update_value+0x4d5/0x540 kernel/bpf/syscall.c:203
 map_update_elem+0x53a/0x6f0 kernel/bpf/syscall.c:1641
 __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5648
 __do_sys_bpf kernel/bpf/syscall.c:5767 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5765 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5765
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f61ef87dd29
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:00007f61ef3de0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f61ef9ac050 RCX: 00007f61ef87dd29
RDX: 0000000000000020 RSI: 00000000200004c0 RDI: 0000000000000002
RBP: 00007f61ef8ca47e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f61ef9ac050 R15: 00007ffdbf4c4388
 </TASK>