From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gdb-prs-return-12141-listarch-gdb-prs=sources.redhat.com@sourceware.org>
Received: (qmail 19953 invoked by alias); 9 Aug 2012 19:11:28 -0000
Received: (qmail 19935 invoked by uid 22791); 9 Aug 2012 19:11:27 -0000
X-SWARE-Spam-Status: No, hits=-3.0 required=5.0
	tests=ALL_TRUSTED,AWL,BAYES_00,TW_XC
X-Spam-Check-By: sourceware.org
Received: from localhost (HELO sourceware.org) (127.0.0.1)
    by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 09 Aug 2012 19:11:09 +0000
From: "hjl.tools at gmail dot com" <sourceware-bugzilla@sourceware.org>
To: gdb-prs@sourceware.org
Subject: [Bug breakpoints/14446] New: breakpoints may not work on jitted code
Date: Thu, 09 Aug 2012 19:11:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gdb
X-Bugzilla-Component: breakpoints
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: hjl.tools at gmail dot com
X-Bugzilla-Status: NEW
X-Bugzilla-Priority: P2
X-Bugzilla-Assigned-To: unassigned at sourceware dot org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-14446-4717@http.sourceware.org/bugzilla/>
X-Bugzilla-URL: http://sourceware.org/bugzilla/
Auto-Submitted: auto-generated
Content-Type: text/plain; charset="UTF-8"
MIME-Version: 1.0
Mailing-List: contact gdb-prs-help@sourceware.org; run by ezmlm
Precedence: bulk
List-Id: <gdb-prs.sourceware.org>
List-Subscribe: <mailto:gdb-prs-subscribe@sourceware.org>
List-Archive: <http://sourceware.org/ml/gdb-prs/>
List-Post: <mailto:gdb-prs@sourceware.org>
List-Help: <mailto:gdb-prs-help@sourceware.org>, <http://sourceware.org/lists.html#faqs>
Sender: gdb-prs-owner@sourceware.org
X-SW-Source: 2012-q3/txt/msg00192.txt.bz2

http://sourceware.org/bugzilla/show_bug.cgi?id=14446

             Bug #: 14446
           Summary: breakpoints may not work on jitted code
           Product: gdb
           Version: HEAD
            Status: NEW
          Severity: normal
          Priority: P2
         Component: breakpoints
        AssignedTo: unassigned@sourceware.org
        ReportedBy: hjl.tools@gmail.com
    Classification: Unclassified


What happens are

1. V8 initializes memory for code with 0xdeadbeef.
2. When you set breakpoint in GDB, gdb saves and replaces one byte,
which happens to be 0xef in 0xdeadbeef, with 0xcc.
3. V8 writes out real instructions in memory.
4. When breakpoint is hit, GDB replaces 0xcc with 0xef.
5. V8 crashes due to 0xef.

-- 
Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.