From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 2664 invoked by alias); 21 Sep 2009 23:01:15 -0000 Received: (qmail 2655 invoked by uid 22791); 21 Sep 2009 23:01:14 -0000 X-SWARE-Spam-Status: No, hits=-2.3 required=5.0 tests=AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from mailhost.u-strasbg.fr (HELO mailhost.u-strasbg.fr) (130.79.200.154) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 21 Sep 2009 23:01:10 +0000 Received: from baal.u-strasbg.fr (baal.u-strasbg.fr [IPv6:2001:660:2402::41]) by mailhost.u-strasbg.fr (8.14.2/jtpda-5.5pre1) with ESMTP id n8LN17Eh018244 for ; Tue, 22 Sep 2009 01:01:07 +0200 (CEST) (envelope-from muller@ics.u-strasbg.fr) Received: from mailserver.u-strasbg.fr (ms2.u-strasbg.fr [IPv6:2001:660:2402:d::11]) by baal.u-strasbg.fr (8.14.0/jtpda-5.5pre1) with ESMTP id n8LN17Ak098695 for ; Tue, 22 Sep 2009 01:01:07 +0200 (CEST) (envelope-from muller@ics.u-strasbg.fr) Received: from d620muller (lec67-4-82-230-53-140.fbx.proxad.net [82.230.53.140]) (user=mullerp mech=LOGIN) by mailserver.u-strasbg.fr (8.14.3/jtpda-5.5pre1) with ESMTP id n8LN16Q8081818 (version=TLSv1/SSLv3 cipher=RC4-MD5 bits=128 verify=NO) for ; Tue, 22 Sep 2009 01:01:07 +0200 (CEST) (envelope-from muller@ics.u-strasbg.fr) From: "Pierre Muller" To: References: <001d01ca3ace$4878c9f0$d96a5dd0$@u-strasbg.fr> <20090921222637.GC17886@ednor.casa.cgf.cx> <000001ca3b0b$d8310250$889306f0$@u-strasbg.fr> In-Reply-To: <000001ca3b0b$d8310250$889306f0$@u-strasbg.fr> Subject: [RFA-v2] windows-nat.c Cygwin saved_context fix Date: Mon, 21 Sep 2009 23:01:00 -0000 Message-ID: <000601ca3b0f$6b694610$423bd230$@u-strasbg.fr> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2009-09/txt/msg00690.txt.bz2 After testing, setting suspended field to -1 seems to work equally well for me. Here is an updated patch: 2009-09-22 Pierre Muller * windows-nat.c (saved_threadid): New variable. (do_windows_fetch_inferior_registers): Check for correct thread id and set suspended field to -1 if it is zero. (handle_output_debug_string): Set saved_threadid. Index: src/gdb/windows-nat.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D RCS file: /cvs/src/src/gdb/windows-nat.c,v retrieving revision 1.197 diff -u -p -r1.197 windows-nat.c --- src/gdb/windows-nat.c 21 Sep 2009 22:37:59 -0000 1.197 +++ src/gdb/windows-nat.c 21 Sep 2009 22:53:11 -0000 @@ -97,6 +97,7 @@ static CORE_ADDR cygwin_load_start; static CORE_ADDR cygwin_load_end; #endif =20 +static int saved_threadid; static int have_saved_context; /* True if we've saved context from a cygwin signal. */ static CONTEXT saved_context; /* Containes the saved context from a cygwin signal. */ =20 @@ -381,11 +382,15 @@ do_windows_fetch_inferior_registers (str if (current_thread->reload_context) { #ifdef __COPY_CONTEXT_SIZE - if (have_saved_context) + if (have_saved_context && current_thread->id =3D=3D saved_threadid) { /* Lie about where the program actually is stopped since cygwin has informed us that we should consider the signal to have occurred at another location which is stored in "saved_context. */ + if (!current_thread->suspended) + /* Set suspended to -1 to avoid resetting reload_context + later in get_thread. */=20 + current_thread->suspended =3D -1; memcpy (¤t_thread->context, &saved_context, __COPY_CONTEXT_SIZE); have_saved_context =3D 0; } @@ -863,6 +868,7 @@ handle_output_debug_string (struct targe &saved_context, __COPY_CONTEXT_SIZE, &n) && n =3D=3D __COPY_CONTEXT_SIZE) have_saved_context =3D 1; + saved_threadid =3D retval; current_event.dwThreadId =3D retval; } } > -----Message d'origine----- > De=A0: gdb-patches-owner@sourceware.org [mailto:gdb-patches- > owner@sourceware.org] De la part de Pierre Muller > Envoy=E9=A0: Tuesday, September 22, 2009 12:36 AM > =C0=A0: gdb-patches@sourceware.org > Objet=A0: RE: [RFA] windows-nat.c Cygwin save_context fix >=20 >=20 >=20 > > -----Message d'origine----- > > De=A0: Christopher Faylor [mailto:cgf-use-the-mailinglist- > > please@sourceware.org] > > Envoy=E9=A0: Tuesday, September 22, 2009 12:27 AM > > =C0=A0: gdb-patches@sourceware.org; Pierre Muller > > Objet=A0: Re: [RFA] windows-nat.c Cygwin save_context fix > > > > On Mon, Sep 21, 2009 at 05:14:57PM +0200, Pierre Muller wrote: > > > Cygwin has a way to give a "fake" context for > > >an exception using a OUTPUT_DEBUG_STRING_EVENT. > > > > > > While trying to debug some crashes inside cygwin dll, > > >I realized the the saved_context code has a problem. > > > > > > The saved context was correctly written to the thread_info > > >struct, but later overwritten by a call to GetThreadContext. > > > > > > After the cygwin special output_debug_string was correctly > > >converted into a context stored in saved_context. > > > The next call to do_windows_fetch_inferior_registers > > >then copied this context to the thread_info struct, > > >set the reload_context field to zero. > > > > > > But a later call to thread_rec() with get_context=3D1 > > >can reset reload_context to one, if suspended field > > >is zero (this only happens if it is not the main thread). > > > > > > My patch fixes the problem by explicitly calling > > >SuspendThread for the threaded of the saved_context > > >if suspended is still zero at that point. > > > > > > > > >Pierre Muller > > >Pascal language support maintainer for GDB > > > > > > > > > > > >2009-09-21 Pierre Muller > > > > > > * src/gdb/windows-nat.c (saved_threadid): New variable. > > > (do_windows_fetch_inferior_registers): Check for correct thread > > id > > > and force call to SuspendThread if needed. > > > (handle_output_debug_string): Set saved_threadid. > > > > I REALLY hate SuspendThread and am not likely to accept a patch which > > uses it as a solution. >=20 > I don't think that we really need to call SuspendThread, > in fact, I suspect the best would be to set suspended > to -1 as for main_threadid. I will try to check out if this also works. >=20 > > I don't really understand the scenario that you are talking about > since > > I (obviously?) have no problems debugging SEGVs in cygwin. However, >=20 > I was trying to debug a home compiled expect > linked to 8.5.7 tcl library, that was call abort, > and the subsequent cygwin stackdump was segfaulting. >=20 > > would just removing the "have_saved_context =3D 0;" from > > do_windows_fetch_inferior_registers fix the problem? >=20 > But them we need to be really careful about to where > we should reset it to zero, otherwise we might end up > by still copying saved_context, even after having reran the debuggee, > no? >=20 > Pierre >=20