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From: "Bryce McKinlay" <bryce@mckinlay.net.nz>
To: "Andrew Haley" <aph@redhat.com>
Cc: "Java Patch List" <java-patches@gcc.gnu.org>,
	 	"Jakub Jelinek" <jakub@redhat.com>,
	 	"Lillian Angel" <langel@redhat.com>
Subject: Re: Remove data race in libgcj interpreter
Date: Fri, 22 Aug 2008 12:51:00 -0000	[thread overview]
Message-ID: <7230133d0808220510n5626ea9fx2a372af41925de77@mail.gmail.com> (raw)
In-Reply-To: <48AD67B2.4040308@redhat.com>

On Thu, Aug 21, 2008 at 2:03 PM, Andrew Haley <aph@redhat.com> wrote:

> I've discovered a nasty data race in libgcj's interpreter.
>
> It is the cause of several bug reports, in particular
> https://bugzilla.redhat.com/show_bug.cgi?id=458921
>
> An optimization rerwites instructions of the form
>
>  invokespecial <constant pool index>
>
> to
>
>  invokespecial_resolved <address>
>
> the first time that each invokespecial is encountered.
>
> However, in the presence of multiple threads this breaks.

Ahh, yeah. I remember this bug:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=8995

As Tom suggests, the proper fix may be to do all the rewriting in the
compile phase, which is protected by a lock.

There is at least one other interpreter bug which shows up only on
multi-core systems:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16902

  parent reply	other threads:[~2008-08-22 12:12 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-21 13:31 Andrew Haley
2008-08-21 21:54 ` Andrew Haley
2008-08-22 12:12   ` gij: more thread-safety fixes Andrew Haley
2008-08-22 12:51 ` Bryce McKinlay [this message]
2008-08-24  1:46   ` Remove data race in libgcj interpreter Andrew Haley
2008-09-04 16:00 ` Andrew Haley
2008-09-04 16:12   ` David Daney
2008-09-04 16:25     ` Andrew Haley
2008-09-04 18:37       ` David Daney
2008-09-05  9:39   ` Boehm, Hans
2008-09-05 11:28     ` Andrew Haley
2008-09-06  9:26       ` Hans Boehm
2008-09-08 17:42         ` Andrew Haley
2008-09-22 14:25           ` Andrew Haley

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