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Date: Thu, 06 Mar 2014 00:12:35 +0100
From: Richard Weinberger <richard@nod.at>
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To: Bill Pringlemeir <bpringlemeir@nbsps.com>
Subject: Re: UBI leb_write_unlock NULL pointer Oops (continuation)
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Am 05.03.2014 22:42, schrieb Bill Pringlemeir:
> On  5 Mar 2014, bpringlemeir@nbsps.com wrote:
> 
>> On  5 Mar 2014, richard@nod.at wrote:
> 
>>> The solution is rather trivial.
> 
> [snip]
> 
>> Still, the logic of ubi_eba_copy_leb() seems really weird to me.  I
>> don't understand,
> 
>> It looks like a double reference count decrement.  Maybe they operate on
>> different ltree nodes, but then the locks mis-match.
> 
> 	if (down_write_trylock(&le->mutex))
> 		return 0;
> 
> Ah, I mis-understood.  The path where the lock is taken doesn't
> decrement the 'users' count; I was thinking of '0' as fail.

Welcome to UNIX where 0 is success. :-)

Thanks,
//richard