Re: [BUG] btrfs: MAX_LOCKDEP_CHAIN_HLOCKS too low!

[Qu Wenruo]

On 2023/6/27 07:40, Mirsad Goran Todorovac wrote:
> Hi,
>
> There is a bug apparently in btrfs file system.
>
> The platform is an assembled box with Ryzen 9 processor and ASRock X670E PG
> Lightning motherboard.
>
> I do not have a reproducer, just kernel log:
>
> Jun 26 20:41:58 defiant kernel: [ 2273.786736] BUG:
> MAX_LOCKDEP_CHAIN_HLOCKS too low!

This is really what it said.

The setting is too low for certain workload.

In fact Fedora is already increasing this value.
If you want lockdep, I guess that's the only way to go.

Thanks,
Qu
> Jun 26 20:41:58 defiant kernel: [ 2273.786742] turning off the locking
> correctness validator.
> Jun 26 20:41:58 defiant kernel: [ 2273.786743] CPU: 20 PID: 6316 Comm:
> URL Classifier Not tainted 6.4.0-kmlk-netdbg-iwlwifi #3
> Jun 26 20:41:58 defiant kernel: [ 2273.786746] Hardware name: ASRock
> X670E PG Lightning/X670E PG Lightning, BIOS 1.21 04/26/2023
> Jun 26 20:41:58 defiant kernel: [ 2273.786748] Call Trace:
> Jun 26 20:41:58 defiant kernel: [ 2273.786749]  <TASK>
> Jun 26 20:41:58 defiant kernel: [ 2273.786751]  dump_stack_lvl+0x60/0xc0
> Jun 26 20:41:58 defiant kernel: [ 2273.786757]  dump_stack+0x10/0x20
> Jun 26 20:41:58 defiant kernel: [ 2273.786759]
> __lock_acquire+0x1dae/0x2340
> Jun 26 20:41:58 defiant kernel: [ 2273.786764]  lock_acquire+0xca/0x2c0
> Jun 26 20:41:58 defiant kernel: [ 2273.786767]  ? kmemleak_free+0x36/0xc0
> Jun 26 20:41:58 defiant kernel: [ 2273.786772]
> _raw_spin_lock_irqsave+0x4e/0x80
> Jun 26 20:41:58 defiant kernel: [ 2273.786775]  ? kmemleak_free+0x36/0xc0
> Jun 26 20:41:58 defiant kernel: [ 2273.786778]  kmemleak_free+0x36/0xc0
> Jun 26 20:41:58 defiant kernel: [ 2273.786781]
> slab_free_freelist_hook.constprop.0+0xe7/0x210
> Jun 26 20:41:58 defiant kernel: [ 2273.786784]  ?
> add_delayed_ref_head+0x24e/0x280 [btrfs]
> Jun 26 20:41:58 defiant kernel: [ 2273.786843]  kmem_cache_free+0x1a4/0x320
> Jun 26 20:41:58 defiant kernel: [ 2273.786847]
> add_delayed_ref_head+0x24e/0x280 [btrfs]
> Jun 26 20:41:58 defiant kernel: [ 2273.786881]
> btrfs_add_delayed_tree_ref+0x284/0x450 [btrfs]
> Jun 26 20:41:58 defiant kernel: [ 2273.786912]
> btrfs_free_tree_block+0xc0/0x2d0 [btrfs]
> Jun 26 20:41:58 defiant kernel: [ 2273.786946]  btrfs_del_leaf+0xb8/0xf0
> [btrfs]
> Jun 26 20:41:58 defiant kernel: [ 2273.786975]
> btrfs_del_items+0x46b/0x4e0 [btrfs]
> Jun 26 20:41:58 defiant kernel: [ 2273.787004]
> btrfs_delete_one_dir_name+0xf9/0x120 [btrfs]
> Jun 26 20:41:58 defiant kernel: [ 2273.787034]
> __btrfs_unlink_inode+0xb5/0x4e0 [btrfs]
> Jun 26 20:41:58 defiant kernel: [ 2273.787067]  btrfs_unlink+0xdb/0x150
> [btrfs]
> Jun 26 20:41:58 defiant kernel: [ 2273.787094]  vfs_unlink+0x131/0x2a0
> Jun 26 20:41:58 defiant kernel: [ 2273.787098]  do_unlinkat+0x1b1/0x2d0
> Jun 26 20:41:58 defiant kernel: [ 2273.787102]  __x64_sys_unlink+0x42/0x70
> Jun 26 20:41:58 defiant kernel: [ 2273.787104]  do_syscall_64+0x59/0x90
> Jun 26 20:41:58 defiant kernel: [ 2273.787107]  ?
> syscall_exit_to_user_mode+0x39/0x60
> Jun 26 20:41:58 defiant kernel: [ 2273.787110]  ? do_syscall_64+0x69/0x90
> Jun 26 20:41:58 defiant kernel: [ 2273.787113]  ?
> syscall_exit_to_user_mode+0x39/0x60
> Jun 26 20:41:58 defiant kernel: [ 2273.787116]  ? do_syscall_64+0x69/0x90
> Jun 26 20:41:58 defiant kernel: [ 2273.787118]  ? do_syscall_64+0x69/0x90
> Jun 26 20:41:58 defiant kernel: [ 2273.787120]  ? do_syscall_64+0x69/0x90
> Jun 26 20:41:58 defiant kernel: [ 2273.787122]
> entry_SYSCALL_64_after_hwframe+0x72/0xdc
> Jun 26 20:41:58 defiant kernel: [ 2273.787124] RIP: 0033:0x7fe80911625b
> Jun 26 20:41:58 defiant kernel: [ 2273.787127] Code: f0 ff ff 73 01 c3
> 48 8b 0d d2 2b 10 00 f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 84 00 00 00 00
> 00 f3 0f 1e fa b8 57 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b
> 0d a5 2b 10 00 f7 d8 64 89 01 48
> Jun 26 20:41:58 defiant kernel: [ 2273.787129] RSP:
> 002b:00007fe7da0895f8 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
> Jun 26 20:41:58 defiant kernel: [ 2273.787131] RAX: ffffffffffffffda
> RBX: 00007fe77e9c29d0 RCX: 00007fe80911625b
> Jun 26 20:41:58 defiant kernel: [ 2273.787133] RDX: 00007fe7da089620
> RSI: 00007fe77e705608 RDI: 00007fe77e705608
> Jun 26 20:41:58 defiant kernel: [ 2273.787134] RBP: 0000000080520015
> R08: 0000000000000000 R09: 0000000000000053
> Jun 26 20:41:58 defiant kernel: [ 2273.787135] R10: 0000000000000100
> R11: 0000000000000206 R12: 00007fe77e9c2a70
> Jun 26 20:41:58 defiant kernel: [ 2273.787137] R13: 00007fe77e9c29d0
> R14: 0000000000000000 R15: 0000000000000001
> Jun 26 20:41:58 defiant kernel: [ 2273.787140]  </TASK>
>
> Later the machine crashed completely, with the broken record sound
> during the
> "make kselftest", which I will try to reproduce later.
>
> The config and lshw are in attachment.
>
> The kernel is the recent 6.4.0 from torvalds tree, with Ubuntu generic
> config
> merged with per kselftest configs.
>
> I understand that the bugs with locking are extremely hard to reproduce, so
> I add this bug report for documentation sake. >
> Best regards,
> Mirsad Todorovac