======================================================
WARNING: possible circular locking dependency detected
6.9.0-rc7-syzkaller-00012-gdccb07f2914c #0 Not tainted
------------------------------------------------------
syz-executor.0/7205 is trying to acquire lock:
ffff88806b529558 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:2960 [inline]
ffff88806b529558 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3359 [inline]
ffff88806b529558 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0xda/0xbe0 kernel/rcu/tree.c:3444

but task is already holding lock:
ffff888026c5b1f8 (&trie->lock){..-.}-{2:2}, at: trie_delete_elem+0xb0/0x7e0 kernel/bpf/lpm_trie.c:451

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&trie->lock){..-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
       trie_delete_elem+0xb0/0x7e0 kernel/bpf/lpm_trie.c:451
       ___bpf_prog_run+0x3e51/0xabd0 kernel/bpf/core.c:1997
       __bpf_prog_run32+0xc1/0x100 kernel/bpf/core.c:2236
       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+0x151/0x420 kernel/trace/bpf_trace.c:2420
       __bpf_trace_timer_start+0xc7/0x100 include/trace/events/timer.h:52
       trace_timer_start include/trace/events/timer.h:52 [inline]
       enqueue_timer+0x2b4/0x550 kernel/time/timer.c:664
       internal_add_timer kernel/time/timer.c:689 [inline]
       __mod_timer+0x8d7/0xdc0 kernel/time/timer.c:1184
       tun_flow_init drivers/net/tun.c:1356 [inline]
       tun_net_init+0x19c/0x510 drivers/net/tun.c:987
       register_netdevice+0x59f/0x1ca0 net/core/dev.c:10210
       tun_set_iff drivers/net/tun.c:2851 [inline]
       __tun_chr_ioctl+0x25b8/0x4770 drivers/net/tun.c:3120
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:904 [inline]
       __se_sys_ioctl fs/ioctl.c:890 [inline]
       __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:890
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&base->lock){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
       lock_timer_base+0x5d/0x220 kernel/time/timer.c:1052
       __mod_timer+0x426/0xdc0 kernel/time/timer.c:1133
       add_timer_global+0x8a/0xc0 kernel/time/timer.c:1331
       __queue_delayed_work+0x1ba/0x2e0 kernel/workqueue.c:2580
       queue_delayed_work_on+0x10e/0x130 kernel/workqueue.c:2608
       kvfree_call_rcu+0x749/0xbe0 kernel/rcu/tree.c:3472
       rtnl_register_internal+0x343/0x670 net/core/rtnetlink.c:265
       rtnl_register+0x34/0x80 net/core/rtnetlink.c:315
       ip_rt_init+0x343/0x450 net/ipv4/route.c:3720
       ip_init+0xe/0x20 net/ipv4/ip_output.c:1663
       inet_init+0x3f0/0x6f0 net/ipv4/af_inet.c:2023
       do_one_initcall+0x128/0x700 init/main.c:1245
       do_initcall_level init/main.c:1307 [inline]
       do_initcalls init/main.c:1323 [inline]
       do_basic_setup init/main.c:1342 [inline]
       kernel_init_freeable+0x69d/0xca0 init/main.c:1555
       kernel_init+0x1c/0x2b0 init/main.c:1444
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #0 (krc.lock){..-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3869 [inline]
       __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
       lock_acquire kernel/locking/lockdep.c:5754 [inline]
       lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
       __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
       _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
       krc_this_cpu_lock kernel/rcu/tree.c:2960 [inline]
       add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3359 [inline]
       kvfree_call_rcu+0xda/0xbe0 kernel/rcu/tree.c:3444
       trie_delete_elem+0x593/0x7e0 kernel/bpf/lpm_trie.c:524
       ___bpf_prog_run+0x3e51/0xabd0 kernel/bpf/core.c:1997
       __bpf_prog_run32+0xc1/0x100 kernel/bpf/core.c:2236
       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_run3+0x167/0x440 kernel/trace/bpf_trace.c:2421
       trace_kmem_cache_free include/trace/events/kmem.h:114 [inline]
       kmem_cache_free+0x1d4/0x390 mm/slub.c:4349
       jbd2_free_handle include/linux/jbd2.h:1596 [inline]
       jbd2_journal_stop+0x711/0xe10 fs/jbd2/transaction.c:1973
       __ext4_journal_stop+0xdd/0x210 fs/ext4/ext4_jbd2.c:134
       ext4_rmdir+0xad4/0xf20 fs/ext4/namei.c:3225
       vfs_rmdir fs/namei.c:4206 [inline]
       vfs_rmdir+0x203/0x660 fs/namei.c:4183
       do_rmdir+0x3a2/0x410 fs/namei.c:4265
       __do_sys_unlinkat fs/namei.c:4441 [inline]
       __se_sys_unlinkat fs/namei.c:4435 [inline]
       __x64_sys_unlinkat+0xf3/0x130 fs/namei.c:4435
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  krc.lock --> &base->lock --> &trie->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&trie->lock);
                               lock(&base->lock);
                               lock(&trie->lock);
  lock(krc.lock);

 *** DEADLOCK ***

5 locks held by syz-executor.0/7205:
 #0: ffff88802371e420 (sb_writers#5){.+.+}-{0:0}, at: do_rmdir+0x1e4/0x410 fs/namei.c:4249
 #1: ffff8880573dd400 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:830 [inline]
 #1: ffff8880573dd400 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: do_rmdir+0x235/0x410 fs/namei.c:4253
 #2: ffff88803002d400 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: inode_lock include/linux/fs.h:795 [inline]
 #2: ffff88803002d400 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: vfs_rmdir fs/namei.c:4195 [inline]
 #2: ffff88803002d400 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: vfs_rmdir+0xe9/0x660 fs/namei.c:4183
 #3: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #3: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #3: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2380 [inline]
 #3: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0xf8/0x440 kernel/trace/bpf_trace.c:2421
 #4: ffff888026c5b1f8 (&trie->lock){..-.}-{2:2}, at: trie_delete_elem+0xb0/0x7e0 kernel/bpf/lpm_trie.c:451

stack backtrace:
CPU: 3 PID: 7205 Comm: syz-executor.0 Not tainted 6.9.0-rc7-syzkaller-00012-gdccb07f2914c #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
 check_noncircular+0x31a/0x400 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 kernel/locking/lockdep.c:3869 [inline]
 __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
 lock_acquire kernel/locking/lockdep.c:5754 [inline]
 lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 krc_this_cpu_lock kernel/rcu/tree.c:2960 [inline]
 add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3359 [inline]
 kvfree_call_rcu+0xda/0xbe0 kernel/rcu/tree.c:3444
 trie_delete_elem+0x593/0x7e0 kernel/bpf/lpm_trie.c:524
 ___bpf_prog_run+0x3e51/0xabd0 kernel/bpf/core.c:1997
 __bpf_prog_run32+0xc1/0x100 kernel/bpf/core.c:2236
 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_run3+0x167/0x440 kernel/trace/bpf_trace.c:2421
 trace_kmem_cache_free include/trace/events/kmem.h:114 [inline]
 kmem_cache_free+0x1d4/0x390 mm/slub.c:4349
 jbd2_free_handle include/linux/jbd2.h:1596 [inline]
 jbd2_journal_stop+0x711/0xe10 fs/jbd2/transaction.c:1973
 __ext4_journal_stop+0xdd/0x210 fs/ext4/ext4_jbd2.c:134
 ext4_rmdir+0xad4/0xf20 fs/ext4/namei.c:3225
 vfs_rmdir fs/namei.c:4206 [inline]
 vfs_rmdir+0x203/0x660 fs/namei.c:4183
 do_rmdir+0x3a2/0x410 fs/namei.c:4265
 __do_sys_unlinkat fs/namei.c:4441 [inline]
 __se_sys_unlinkat fs/namei.c:4435 [inline]
 __x64_sys_unlinkat+0xf3/0x130 fs/namei.c:4435
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa25c47d547
Code: 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 07 01 00 00 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:00007ffe23172cf8 EFLAGS: 00000207 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 00007fa25c47d547
RDX: 0000000000000200 RSI: 00007ffe23173e70 RDI: 00000000ffffff9c
RBP: 00007fa25c4c937e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000207 R12: 00007ffe23173e70
R13: 00007fa25c4c937e R14: 000000000001ce0d R15: 000000000000000c
 </TASK>
EXT4-fs (loop0): unmounting filesystem 00000004-0000-0000-0000-000000000000.