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List:       busybox
Subject:    Re: Re: bug-report: ash: fix a memory leak
From:       Rongqing Li <rongqing.li () windriver ! com>
Date:       2015-09-28 2:17:20
Message-ID: 5608A330.2010104 () windriver ! com
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On 2014年12月24日 13:53, Rich Felker wrote:
> On Wed, Dec 24, 2014 at 10:32:19AM +0800, yhu2 wrote:
>> The script which triggers the leak:
>>
>> while true
>>    do
>>      while true
>>        do
>>          break;
>>      done</dev/null
>> done
>>
>> someone had fixed this bug, the commit is:
>> http://git.busybox.net/busybox/commit/shell/ash.c?id=4ba6c5d3ba3d2c7922aff6b5c2e73b8325f1cf17
>>
>> but this commit results in crash running some shell scripts, so it was reverted.
>>
>>
>> I am trying to resolve this defect,any commnent would be appreciated!
>
> There is no easy fix. The patch you sent is incorrect. The problem is
> that the "stack model" used for allocation in ash is semantically
> wrong, and needs to be replaced with a dependency-tree model or
> something else that can handle freeing one object without freeing all
> subsequently-allocated objects.
>
> As a workaround, it might be possible to code a hack to reuse the
> existing copy of the string on the allocation stack rather than
> allocating a new copy whenever an existing copy already exists. This
> would not solve the general case (e.g. when the redirection uses a
> different file on each iteration) but it would solve the case above, I
> think. It might be worth pursuing this approach if nobody is available
> to work on the proper fix in the near future.
>

Hi Rich Felker:

Could you submit your suggested workaround?

-Roy


> Rich
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>
>

-- 
Best Reagrds,
Roy | RongQing Li
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