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Date: Mon, 7 Aug 2017 20:18:34 +0000
From: Eric Wong <e@80x24.org>
To: Jeremy Evans <code@jeremyevans.net>
Cc: Pere Joan Martorell <pere.joan@camaloon.com>,
	unicorn-public@bogomips.org,
	Philip Cunningham <philip@irisconnect.co.uk>,
	Jonathan del Strother <maillist@steelskies.com>
Subject: Re: Random crash when sending USR2 + QUIT signals to Unicorn process
Message-ID: <20170807201834.GA49506@ailurophile>
References: <CABre=GOGaByZSEUnCT6CPWDQb8aDXu8oj1W3oaAe6sD3NM4ghQ@mail.gmail.com>
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 <20170714225015.GD68067@jeremyevans.local>
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 <20170715013411.GE68067@jeremyevans.local>
 <20170715044523.GA19602@starla>
 <20170715075631.GF68067@jeremyevans.local>
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Jeremy Evans <code@jeremyevans.net> wrote:
> On 07/24 01:25, Eric Wong wrote:
> > Jeremy Evans <code@jeremyevans.net> wrote:
> > > Running with GC.stress didn't catch the error for me.  But I'm using a
> > > fairly old compiler (GCC 4.2.1, the OpenBSD default), so this may be
> > > something that only shows up on a newer compiler that does more
> > > optimizations.
> > 
> > Pere: just curious if you've had a chance to test my patch for
> > sequel_pg from Jeremy's latest sequel_pg.git
> > 
> > In any case, I'm certain my patch fixes a bug which manifests
> > in a compiler-dependent manner; but here could always be other
> > bugs in a similar vein.  Thanks.
> 
> I can't get it to crash with sequel_pg 1.7.0 when compiled using clang
> 4.0.0 either.  I even tried to build a special program designed to
> trigger the crash.

>From anecdotes on ruby-core, clang still seems less aggressive
at optimizations than modern gcc.

Fwiw, a few GC bugs in Ruby trunk got fixed recently and the
fixes should be in 2.4.2 (soon):
https://public-inbox.org/ruby-core/?q=T_NONE+d%3A20161225..20170808

Not identical to T_NODE which Pere got, but if it's a GC bug,
but both T_NONE and T_NODE triggers are symptoms of GC bugs.