======================================================
WARNING: possible circular locking dependency detected
6.9.0-rc7-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.2/7082 is trying to acquire lock:
ffff8880b9529558 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:2960 [inline]
ffff8880b9529558 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3359 [inline]
ffff8880b9529558 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0xda/0xbe0 kernel/rcu/tree.c:3444

but task is already holding lock:
ffff88806a7ed9f8 (&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
       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
       queue_delayed_work include/linux/workqueue.h:620 [inline]
       batadv_mcast_start_timer net/batman-adv/multicast.c:71 [inline]
       batadv_mcast_mla_update+0x155e/0x3200 net/batman-adv/multicast.c:950
       process_one_work+0x9a9/0x1ac0 kernel/workqueue.c:3267
       process_scheduled_works kernel/workqueue.c:3348 [inline]
       worker_thread+0x6c8/0xf70 kernel/workqueue.c:3429
       kthread+0x2c1/0x3a0 kernel/kthread.c:388
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #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
       __bpf_trace_ext4_forget+0x102/0x140 include/trace/events/ext4.h:1186
       trace_ext4_forget include/trace/events/ext4.h:1186 [inline]
       __ext4_forget+0x30b/0x4a0 fs/ext4/ext4_jbd2.c:272
       ext4_free_blocks+0xfef/0x1b60 fs/ext4/mballoc.c:6635
       ext4_remove_blocks fs/ext4/extents.c:2521 [inline]
       ext4_ext_rm_leaf fs/ext4/extents.c:2686 [inline]
       ext4_ext_remove_space+0x2eaf/0x4510 fs/ext4/extents.c:2934
       ext4_ext_truncate+0x240/0x2f0 fs/ext4/extents.c:4440
       ext4_truncate+0xe3c/0x1400 fs/ext4/inode.c:4146
       ext4_evict_inode+0x7ae/0x17d0 fs/ext4/inode.c:258
       evict+0x2ed/0x6c0 fs/inode.c:667
       iput_final fs/inode.c:1741 [inline]
       iput.part.0+0x5a8/0x7f0 fs/inode.c:1767
       iput+0x5c/0x80 fs/inode.c:1757
       d_delete_notify include/linux/fsnotify.h:307 [inline]
       vfs_rmdir fs/namei.c:4219 [inline]
       vfs_rmdir+0x45a/0x660 fs/namei.c:4183
       do_rmdir+0x3a2/0x410 fs/namei.c:4265
       __do_sys_rmdir fs/namei.c:4284 [inline]
       __se_sys_rmdir fs/namei.c:4282 [inline]
       __x64_sys_rmdir+0xc7/0x110 fs/namei.c:4282
       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 ***

7 locks held by syz-executor.2/7082:
 #0: ffff88802f41e420 (sb_writers#5){.+.+}-{0:0}, at: do_rmdir+0x1e4/0x410 fs/namei.c:4249
 #1: ffff88805e4e4a00 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:830 [inline]
 #1: ffff88805e4e4a00 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: do_rmdir+0x235/0x410 fs/namei.c:4253
 #2: ffff88802f41e610 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x6c0 fs/inode.c:667
 #3: ffff88802f962950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x10db/0x15e0 fs/jbd2/transaction.c:463
 #4: ffff888062210288 (&ei->i_data_sem){++++}-{3:3}, at: ext4_truncate+0xdd6/0x1400 fs/ext4/inode.c:4141
 #5: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #5: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #5: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2380 [inline]
 #5: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0xf8/0x440 kernel/trace/bpf_trace.c:2421
 #6: ffff88806a7ed9f8 (&trie->lock){..-.}-{2:2}, at: trie_delete_elem+0xb0/0x7e0 kernel/bpf/lpm_trie.c:451

stack backtrace:
CPU: 1 PID: 7082 Comm: syz-executor.2 Not tainted 6.9.0-rc7-syzkaller #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+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
 __bpf_trace_ext4_forget+0x102/0x140 include/trace/events/ext4.h:1186
 trace_ext4_forget include/trace/events/ext4.h:1186 [inline]
 __ext4_forget+0x30b/0x4a0 fs/ext4/ext4_jbd2.c:272
 ext4_free_blocks+0xfef/0x1b60 fs/ext4/mballoc.c:6635
 ext4_remove_blocks fs/ext4/extents.c:2521 [inline]
 ext4_ext_rm_leaf fs/ext4/extents.c:2686 [inline]
 ext4_ext_remove_space+0x2eaf/0x4510 fs/ext4/extents.c:2934
 ext4_ext_truncate+0x240/0x2f0 fs/ext4/extents.c:4440
 ext4_truncate+0xe3c/0x1400 fs/ext4/inode.c:4146
 ext4_evict_inode+0x7ae/0x17d0 fs/ext4/inode.c:258
 evict+0x2ed/0x6c0 fs/inode.c:667
 iput_final fs/inode.c:1741 [inline]
 iput.part.0+0x5a8/0x7f0 fs/inode.c:1767
 iput+0x5c/0x80 fs/inode.c:1757
 d_delete_notify include/linux/fsnotify.h:307 [inline]
 vfs_rmdir fs/namei.c:4219 [inline]
 vfs_rmdir+0x45a/0x660 fs/namei.c:4183
 do_rmdir+0x3a2/0x410 fs/namei.c:4265
 __do_sys_rmdir fs/namei.c:4284 [inline]
 __se_sys_rmdir fs/namei.c:4282 [inline]
 __x64_sys_rmdir+0xc7/0x110 fs/namei.c:4282
 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: 0033:0x7fc785e7dca9
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:00007fc786ba30c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000054
RAX: ffffffffffffffda RBX: 00007fc785fabf80 RCX: 00007fc785e7dca9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000100
RBP: 00007fc785ec947e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fc785fabf80 R15: 00007ffc29697468
 </TASK>