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From: Michal Hocko <mhocko@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	William Preston <wpreston@suse.com>,
	Roland McGrath <roland@hack.frob.com>,
	Andreas Schwab <schwab@suse.com>
Subject: Re: [RFC PATCH] kernel/fork: fix CLONE_CHILD_CLEARTID regression in nscd
Date: Tue, 23 Aug 2016 18:03:37 +0200	[thread overview]
Message-ID: <20160823160337.GA25099@dhcp22.suse.cz> (raw)
In-Reply-To: <20160823152711.GA4067@redhat.com>

On Tue 23-08-16 17:27:11, Oleg Nesterov wrote:
> On 08/19, Michal Hocko wrote:
[...]
> > or we do not care about this
> > "regression"
> 
> Honestly, I do not know ;) Personally, I am always scared when it comes
> to the subtle changes like this, you can never know what can be broken.

If _you_ are scarred (after so many years of permanent exposure to this
code) then try to imagine how I am scarred when touching anything in
this area...

> And note that it can be broken 10 years later, like it happened with
> nscd ;)
> 
> But if you send the s/PF_SIGNALED/SIGNAL_GROUP_COREDUMP/ change I will
> ack it ;)

OK, I will repost

> Even if it won't really fix this nscd problem (imo), because
> I guess nscd wants to reset ->clear_child_tid even if the signal was
> sig_kernel_coredump().

Come on, have you ever seen this fine piece of software crashing?
But more seriously, I wouldn't give a damn because nscd is usually the
first thing I disable on my systems but there seem to be people who
would like to use this persistence thingy and even service restart will
break it. So I think we should plug this hole.

Anyway thanks for your review and feedback. As always it is really
appreciated!
-- 
Michal Hocko
SUSE Labs

WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	William Preston <wpreston@suse.com>,
	Roland McGrath <roland@hack.frob.com>,
	Andreas Schwab <schwab@suse.com>
Subject: Re: [RFC PATCH] kernel/fork: fix CLONE_CHILD_CLEARTID regression in nscd
Date: Tue, 23 Aug 2016 18:03:37 +0200	[thread overview]
Message-ID: <20160823160337.GA25099@dhcp22.suse.cz> (raw)
In-Reply-To: <20160823152711.GA4067@redhat.com>

On Tue 23-08-16 17:27:11, Oleg Nesterov wrote:
> On 08/19, Michal Hocko wrote:
[...]
> > or we do not care about this
> > "regression"
> 
> Honestly, I do not know ;) Personally, I am always scared when it comes
> to the subtle changes like this, you can never know what can be broken.

If _you_ are scarred (after so many years of permanent exposure to this
code) then try to imagine how I am scarred when touching anything in
this area...

> And note that it can be broken 10 years later, like it happened with
> nscd ;)
> 
> But if you send the s/PF_SIGNALED/SIGNAL_GROUP_COREDUMP/ change I will
> ack it ;)

OK, I will repost

> Even if it won't really fix this nscd problem (imo), because
> I guess nscd wants to reset ->clear_child_tid even if the signal was
> sig_kernel_coredump().

Come on, have you ever seen this fine piece of software crashing?
But more seriously, I wouldn't give a damn because nscd is usually the
first thing I disable on my systems but there seem to be people who
would like to use this persistence thingy and even service restart will
break it. So I think we should plug this hole.

Anyway thanks for your review and feedback. As always it is really
appreciated!
-- 
Michal Hocko
SUSE Labs

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  reply	other threads:[~2016-08-23 16:19 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-01  8:14 [RFC PATCH] kernel/fork: fix CLONE_CHILD_CLEARTID regression in nscd Michal Hocko
2016-08-01  8:14 ` Michal Hocko
2016-08-03 21:08 ` Oleg Nesterov
2016-08-03 21:08   ` Oleg Nesterov
2016-08-12  9:41   ` Michal Hocko
2016-08-12  9:41     ` Michal Hocko
2016-08-19 13:25     ` Michal Hocko
2016-08-19 13:25       ` Michal Hocko
2016-08-23 15:27       ` Oleg Nesterov
2016-08-23 15:27         ` Oleg Nesterov
2016-08-23 16:03         ` Michal Hocko [this message]
2016-08-23 16:03           ` Michal Hocko

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