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

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Message-ID: <4E57641A.7090909@draigBrady.com>
Date:	Fri, 26 Aug 2011 10:15:06 +0100
From:	Pádraig Brady <P@...igBrady.com>
To:	Neil Horman <nhorman@...driver.com>
CC:	Jovi Zhang <bookjovi@...il.com>, Oleg Nesterov <oleg@...hat.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 08/25/2011 11:55 AM, Neil Horman wrote:
> On Thu, Aug 25, 2011 at 11:03:35AM +0100, Pádraig Brady wrote:
>>
>> Drats I just noticed another problem with not being able to disable core dumps
>> for a process. The `timeout` command from coreutils now tries to propagate
>> the signal from the process it's monitoring up. But since core dumps
>> can't be disabled, abrt will attribute any crashes to `timeout` rather
>> than what it's monitoring. I'll guess we'll have to revert:
>> http://git.sv.gnu.org/gitweb/?p=coreutils.git;a=commitdiff;h=5a647a0
>>
> That suggests to me that we need another flag that user space can control to
> override this behavior.  It appears we may have one too - the PR_SET_DUMPABLE
> flag in the prctl syscall.  Its not POSIX compliant so you'd have to ifdef it
> into coreutils, but it exists, and sounds like exactly what you'd need in the
> above case.  Looking at do_coredump, clearing the PR_SET_DUMPABLE flag with
> prctl causes __get_dumpable to return 0, which skips all the code in do_coredump
> entirely.  I think thats identical behavior to having a zero core limit skip the
> dump.

This would be the first use of prctl in coreutils,
but I think this should handle things.

thanks for that!
Pádraig.
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