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From: ludo@gnu.org (Ludovic Courtès)
To: bug-guile@gnu.org
Cc: guile-devel@gnu.org
Subject: Re: [PATCH] fix for Re: crash in gc with upside-down stack
Date: Fri, 14 Nov 2008 00:40:42 +0100	[thread overview]
Message-ID: <87abc3yz2d.fsf@gnu.org> (raw)
In-Reply-To: 3ae3aa420811131350v12ea6a6dj46f7cc59750d8469@mail.gmail.com

Hi,

"Linas Vepstas" <linasvepstas@gmail.com> writes:

> The patch below fixes a crash during garbage collection, where, during
> the mark-stack phase, the top and bottom of the stack are found to be
> in backwards order, typically because scm_with_guile() was called when
> the stack is much shorter than when a thread was first guilified. That
> is, the stack base pointer is stale, and can be inverted from the stack
> top. If GC runs due to activity in some other thread, the stale base
> pointer leads to the crash (as base-top is approximately 2^32 or 2^64).

Good catch!  I applied it, along with a test case that reproduced the
problem:

  http://git.savannah.gnu.org/gitweb/?p=guile.git;a=commitdiff;h=cd1a1e47b5e781277560d9933a44e6aabd0c9c49

Thanks!

Ludo'.





  reply	other threads:[~2008-11-13 23:40 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-11-13 21:50 [PATCH] fix for Re: crash in gc with upside-down stack Linas Vepstas
2008-11-13 23:40 ` Ludovic Courtès [this message]
2008-11-16  0:17   ` Neil Jerram

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