linux-kernel - Re: [PATCH] coredump: fix pipe coredump when core limit is 0

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Message-ID: <4E527684.3020206@draigBrady.com>
Date:	Mon, 22 Aug 2011 16:32:20 +0100
From:	Pádraig Brady <P@...igBrady.com>
To:	Neil Horman <nhorman@...driver.com>
CC:	Oleg Nesterov <oleg@...hat.com>, bookjovi@...il.com,
	dhowells@...hat.com, roland@...hat.com, viro@...iv.linux.org.uk,
	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] coredump: fix pipe coredump when core limit is 0

On 08/21/2011 11:36 PM, Neil Horman wrote:
> Concur.  The comment should be changed
> Neil
> 
> Oleg Nesterov <oleg@...hat.com> wrote:
> 
>> On 08/21, Oleg Nesterov wrote:
>>>
>>> On 08/21, bookjovi@...il.com wrote:
>>>>
>>>> For non-pipe case, limit 0 also means drop the coredump, so just put
>>>> the zero limit check at do_coredump function begining.
>>>
>>> Neil, what do you think? Should we change the code or the comment?
>>
>> Personally I think we should fix the comment. I think RLIMIT_CORE
>> doesn't apply in this case, limit == 1 check is very special. And
>> this is what linux always did, except between 725eae32 and 898b374a.

Sorry for jumping in late here.
I would really like `ulimit -c 0` to completely disable core dumps,
including not running core_pattern, as I also mentioned here:
https://bugs.launchpad.net/ubuntu/+source/apport/+bug/62511
I noticed this in a script where ctrl-\ was taking a long
time to be registered as the core_pattern was run unconditionally.

Testing on 2.6.38.8-34.fc15.x86_64 here shows the IMHO problematic behavior:

# echo "|/bin/true" > /proc/sys/kernel/core_pattern
# ulimit -c 0
# cat
^\Quit (core dumped)

cheers,
Pádraig.
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