Re: LOR: kern_descrip.c:2277,2278

Hi,

Could you check:

http://lists.freebsd.org/pipermail/freebsd-current/2005-September/056078.html

Best regards,
                        rik

John Baldwin wrote:

>On Monday 17 January 2005 05:07 pm, Bjoern A. Zeeb wrote:
>  
>
>>Hi,
>>
>>I have added the following as LOR #055 to "the LOR page"[1].
>>
>>lock order reversal
>> 1st 0xffffffff80c3a9e8 sleep mtxpool (sleep mtxpool) _at_
>>sys/kern/kern_descrip.c:2277 2nd 0xffffff00222d8a48 filedesc structure
>>(filedesc structure) _at_ sys/kern/kern_descrip.c:2278 KDB: stack backtrace:
>>witness_checkorder() at witness_checkorder+0x5f1
>>_mtx_lock_flags() at _mtx_lock_flags+0x4a
>>dupfdopen() at dupfdopen+0x320
>>kern_open() at kern_open+0x5de
>>syscall() at syscall+0x4ab
>>Xfast_syscall() at Xfast_syscall+0xa8
>>--- syscall (5, FreeBSD ELF64, open), rip = 0x80077e7d0, rsp =
>>0x7fffffffe6f8, rbp = 0x7fffffffec70 ---
>>
>>I can easily reproduce it every boot. It seems to be triggered by
>>Capi4BSD[2] framework which I incorporated in my private tree.
>>
>>Can someone please comment on this ?
>>    
>>
>
>The problem is that FILEDESC_UNLOCK() actually includes an entirely separate 
>lock of its own (it's like an sx lock sort of).  One possible fix might be to 
>change struct file to either use a dedicated mutex pool (instead of the more 
>generic mtxpool_sleep one that is intended only for leaf-lock usage) or to 
>have each struct file include its own mutex rather than using a pool lock.
>  
>