Re: 2.6.26-rc2-mm1: sparc64 - possible recursive locking detected

[Andrew Morton <akpm@linux-foundation.org>]

On Wed, 14 May 2008 20:29:40 +0200 Mariusz Kozlowski <m.kozlowski@tuxland.pl> wrote:

> Hello,
> 
> 	Got this on sparc64 startup:

whoa.  A sparc64 tester?  Thanks!

> =============================================
> [ INFO: possible recursive locking detected ]
> 2.6.26-rc2-mm1 #2
> ---------------------------------------------
> modprobe/514 is trying to acquire lock:
>  (&cls->mutex){--..}, at: [<00000000005ff538>] device_add+0x3c0/0x5c0
> 
> but task is already holding lock:
>  (&cls->mutex){--..}, at: [<000000000060287c>] class_interface_register+0x44/0xe0
> 
> other info that might help us debug this:
> 1 lock held by modprobe/514:
>  #0:  (&cls->mutex){--..}, at: [<000000000060287c>] class_interface_register+0x44/0xe0
> 
> stack backtrace:
> Call Trace:
>  [000000000048cc64] __lock_acquire+0x104c/0x1400
>  [000000000048d098] lock_acquire+0x80/0xa0
>  [0000000000701898] mutex_lock_nested+0xc0/0x4e0
>  [00000000005ff538] device_add+0x3c0/0x5c0
>  [00000000005ff74c] device_register+0x14/0x20
>  [00000000005ff808] device_create+0xb0/0xe0
>  [0000000010012ef8] sg_add+0x160/0x380 [sg]
>  [00000000006028d4] class_interface_register+0x9c/0xe0
>  [0000000000617050] scsi_register_interface+0x18/0x40
>  [000000001001c0a4] init_sg+0xac/0x180 [sg]
>  [00000000004960c8] sys_init_module+0xb0/0x1c0
>  [00000000004463cc] sys32_init_module+0x14/0x20
>  [0000000000406294] linux_sparc_syscall32+0x3c/0x40
>  [0000000000013698] 0x136a0
> 

Yeah, this is a bug which has always been there, afaik.  A
semaphore was converted to a mutex.  Semaphores don't have lockdep
checking, but mutexes do, so we just now got to find out about it. 
Some finger-pointing is occurring over on the scsi list ;)

I assume the machine otherwise works OK?