From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 11974 invoked by alias); 22 Jan 2015 20:37:30 -0000 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 Received: (qmail 11964 invoked by uid 89); 22 Jan 2015 20:37:28 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-2.0 required=5.0 tests=AWL,BAYES_00,SPF_PASS autolearn=ham version=3.3.2 X-HELO: usevmg20.ericsson.net Received: from usevmg20.ericsson.net (HELO usevmg20.ericsson.net) (198.24.6.45) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-SHA encrypted) ESMTPS; Thu, 22 Jan 2015 20:37:22 +0000 Received: from EUSAAHC001.ericsson.se (Unknown_Domain [147.117.188.75]) by usevmg20.ericsson.net (Symantec Mail Security) with SMTP id 18.F0.03307.3EC01C45; Thu, 22 Jan 2015 15:44:52 +0100 (CET) Received: from [142.133.110.232] (147.117.188.8) by smtp-am.internal.ericsson.com (147.117.188.77) with Microsoft SMTP Server id 14.3.195.1; Thu, 22 Jan 2015 15:37:18 -0500 Message-ID: <54C15F7E.5050904@ericsson.com> Date: Fri, 23 Jan 2015 00:13:00 -0000 From: Simon Marchi User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Pedro Alves , CC: Subject: Re: [PATCH v2] Catch exception in value_rtti_indirect_type References: <1411174953-8930-1-git-send-email-simon.marchi@ericsson.com> <54809E38.3080606@redhat.com> <54821670.6020006@ericsson.com> In-Reply-To: <54821670.6020006@ericsson.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2015-01/txt/msg00626.txt.bz2 On 14-12-05 03:32 PM, Simon Marchi wrote: > On 2014-12-04 12:47 PM, Pedro Alves wrote: >> On 09/20/2014 02:02 AM, Simon Marchi wrote: >>> In the situation described in bug 17416 [1], >> >> Could you paste that in the commit log please? > > Done. > >>> an exception thrown in >>> value_ind can propagate too far and leave an half-built variable object, >>> leading to a wrong state. This patch adds a TRY_CATCH to catch it and >>> makes value_rtti_indirect_type return NULL in that case, meaning >>> that the type of the pointed object could not be found. >>> >>> If you want, I can also integrate the test case provided in the bug >> >> Yes please. > > Done. > >>> description. I just don't know how to name it without giving it a >>> ridiculously long name such as >>> mi-var-list-children-with-print-object-on-and-a-null-pointer-to-a-structure-that-contains-a-pointer-to-a-structure.exp. >> >> Perhaps mi-var-list-children-invalid-grandchild.exp. > > Perfect, thanks. > >>> >>> I tested the change on my machine, Ubuntu 14.10 x86-64. >>> >>> gdb/Changelog: >>> >>> * valops.c (value_rtti_indirect_type): Catch exception thrown by >>> value_ind. >>> >>> [1] https://sourceware.org/bugzilla/show_bug.cgi?id=17416 >>> --- >>> gdb/valops.c | 13 ++++++++++++- >>> 1 file changed, 12 insertions(+), 1 deletion(-) >>> >>> diff --git a/gdb/valops.c b/gdb/valops.c >>> index e1decf0..c1a0c86 100644 >>> --- a/gdb/valops.c >>> +++ b/gdb/valops.c >>> @@ -3609,7 +3609,18 @@ value_rtti_indirect_type (struct value *v, int *full, >>> if (TYPE_CODE (type) == TYPE_CODE_REF) >>> target = coerce_ref (v); >>> else if (TYPE_CODE (type) == TYPE_CODE_PTR) >>> - target = value_ind (v); >>> + { >>> + volatile struct gdb_exception except; >>> + >>> + TRY_CATCH (except, RETURN_MASK_ERROR) >>> + { >>> + target = value_ind (v); >>> + } >>> + if (except.error == MEMORY_ERROR) >>> + return NULL; >>> + else if (except.error != GDB_NO_ERROR) >>> + throw_exception (except); >> >> Indentation looks odd. But, could you write it like this instead ? >> >> volatile struct gdb_exception except; >> >> TRY_CATCH (except, RETURN_MASK_ERROR) >> { >> target = value_ind (v); >> } >> if (except.reason < 0) >> { >> if (except.error == MEMORY_ERROR) >> { >> /* Add comment here. */ >> return NULL; >> } >> throw_exception (except); >> } > > Indeed it was odd. I took your suggestion. Here is the updated v2: > > From 4f3924e505d6343c430292e2261d146e66d8799a Mon Sep 17 00:00:00 2001 > From: Simon Marchi > Date: Fri, 19 Sep 2014 21:02:33 -0400 > Subject: [PATCH v2] Catch exception in value_rtti_indirect_type > > In the situation described in bug 17416 [1]: > > * "set print object" is on; > * The variable object is a pointer to a struct, and it contains an > invalid value (e.g. NULL, or random uninitialized value); > * The variable object (struct) has a child which is also a pointer to a > struct; > * We try to use "-var-list-children". > > ... an exception thrown in value_ind can propagate too far and leave an > half-built variable object, leading to a wrong state. This patch adds a > TRY_CATCH to catch it and makes value_rtti_indirect_type return NULL in > that case, meaning that the type of the pointed object could not be > found. > > A test for the fix is also added. > > New in v2: > > * Added test. > * Restructured "catch" code. > * Added details about the bug in commit log. > > gdb/Changelog: > > * valops.c (value_rtti_indirect_type): Catch exception thrown by > value_ind. > > gdb/testsuite/ChangeLog > > * gdb.mi/mi-var-list-children-invalid-grandchild.c: New file. > * gdb.mi/mi-var-list-children-invalid-grandchild.exp: New file. > > [1] https://sourceware.org/bugzilla/show_bug.cgi?id=17416 > --- > .../mi-var-list-children-invalid-grandchild.c | 46 ++++++++++++++++ > .../mi-var-list-children-invalid-grandchild.exp | 63 ++++++++++++++++++++++ > gdb/valops.c | 20 ++++++- > 3 files changed, 128 insertions(+), 1 deletion(-) > create mode 100644 gdb/testsuite/gdb.mi/mi-var-list-children-invalid-grandchild.c > create mode 100644 gdb/testsuite/gdb.mi/mi-var-list-children-invalid-grandchild.exp > > diff --git a/gdb/testsuite/gdb.mi/mi-var-list-children-invalid-grandchild.c b/gdb/testsuite/gdb.mi/mi-var-list-children-invalid-grandchild.c > new file mode 100644 > index 0000000..b67d875 > --- /dev/null > +++ b/gdb/testsuite/gdb.mi/mi-var-list-children-invalid-grandchild.c > @@ -0,0 +1,46 @@ > +/* This testcase is part of GDB, the GNU debugger. > + > + Copyright 2014 Free Software Foundation, Inc. > + > + This program is free software; you can redistribute it and/or modify > + it under the terms of the GNU General Public License as published by > + the Free Software Foundation; either version 3 of the License, or > + (at your option) any later version. > + > + This program is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + GNU General Public License for more details. > + > + You should have received a copy of the GNU General Public License > + along with this program. If not, see . */ > + > +struct inner > +{ > + int a; > +}; > + > +struct outer > +{ > + struct inner *inner; > +}; > + > +int main (void) > +{ > + struct inner inner; > + struct outer outer; > + struct outer *p_outer; > + > + inner.a = 42; > + outer.inner = &inner; > + > + /* We force p_outer to an invalid value, but this also happens naturally > + * when a variable has not been initialized. */ > + > + p_outer = 0; > + /* p_outer set to invalid value */ > + p_outer = &outer; > + /* p_outer set to valid value */ > + > + return 0; > +} > diff --git a/gdb/testsuite/gdb.mi/mi-var-list-children-invalid-grandchild.exp b/gdb/testsuite/gdb.mi/mi-var-list-children-invalid-grandchild.exp > new file mode 100644 > index 0000000..ed8460d > --- /dev/null > +++ b/gdb/testsuite/gdb.mi/mi-var-list-children-invalid-grandchild.exp > @@ -0,0 +1,63 @@ > +# Copyright 2014 Free Software Foundation, Inc. > + > +# This program is free software; you can redistribute it and/or modify > +# it under the terms of the GNU General Public License as published by > +# the Free Software Foundation; either version 3 of the License, or > +# (at your option) any later version. > +# > +# This program is distributed in the hope that it will be useful, > +# but WITHOUT ANY WARRANTY; without even the implied warranty of > +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > +# GNU General Public License for more details. > +# > +# You should have received a copy of the GNU General Public License > +# along with this program. If not, see . > + > +# This is a regression test for bug 17416 > +# https://sourceware.org/bugzilla/show_bug.cgi?id=17416 > + > +load_lib mi-support.exp > +set MIFLAGS "-i=mi" > + > +gdb_exit > +if [mi_gdb_start] { > + continue > +} > + > +standard_testfile > + > +if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } { > + untested mi-var-list-children-invalid-grandchild.exp > + return -1 > +} > + > +mi_delete_breakpoints > +mi_gdb_reinitialize_dir $srcdir/$subdir > +mi_gdb_load ${binfile} > + > +set line_invalid_pointer_value [gdb_get_line_number "p_outer set to invalid value"] > +set line_valid_pointer_value [gdb_get_line_number "p_outer set to valid value"] > + > +# set print object on > +mi_gdb_test "-interpreter-exec console \"set print object on\"" \ > + "(.*=cmd-param-changed,param=\"print object\",value=\"on\".*|)\\^done" \ > + "set print object on" > + > +mi_runto main > + > +mi_continue_to_line $line_invalid_pointer_value "continue to invalid pointer value" > + > +# Create variable object > +mi_gdb_test "-var-create var1 * p_outer" "\\^done,name=\"var1\",numchild=\"1\",value=\"0x0\",type=\"struct outer \\*\",thread-id=\"1\",has_more=\"0\"" "create variable object" > + > +# List children while the pointer is uninitialized. > +# Note: if you remove this -var-list-children, the second one will work. > +mi_gdb_test "-var-list-children var1" "\\^done,numchild=\"1\",children=\\\[child={name=\"var1.inner\",exp=\"inner\",numchild=\"1\",type=\"struct inner \\*\",thread-id=\"1\"}\\\],has_more=\"0\"" "list children #1" > + > +mi_continue_to_line $line_valid_pointer_value "continue to valid pointer value" > + > +# Update and list children again > +mi_gdb_test "-var-update var1" "\\^done,changelist=\\\[{name=\"var1\",in_scope=\"true\",type_changed=\"false\",has_more=\"0\"},{name=\"var1.inner\",in_scope=\"true\",type_changed=\"false\",has_more=\"0\"}\\\]" "update variable object" > + > +mi_gdb_test "-var-list-children var1" "\\^done,numchild=\"1\",children=\\\[child={name=\"var1.inner\",exp=\"inner\",numchild=\"1\",type=\"struct inner \\*\",thread-id=\"1\"}\\\],has_more=\"0\"" "list children #2" > + > diff --git a/gdb/valops.c b/gdb/valops.c > index 4125fc0..d806f27 100644 > --- a/gdb/valops.c > +++ b/gdb/valops.c > @@ -3609,7 +3609,25 @@ value_rtti_indirect_type (struct value *v, int *full, > if (TYPE_CODE (type) == TYPE_CODE_REF) > target = coerce_ref (v); > else if (TYPE_CODE (type) == TYPE_CODE_PTR) > - target = value_ind (v); > + { > + volatile struct gdb_exception except; > + > + TRY_CATCH (except, RETURN_MASK_ERROR) > + { > + target = value_ind (v); > + } > + if (except.reason < 0) > + { > + if (except.error == MEMORY_ERROR) > + { > + /* value_ind threw a memory error. The pointer is NULL or > + contains an uninitialized value: we can't determine any > + type. */ > + return NULL; > + } > + throw_exception (except); > + } > + } > else > return NULL; Ping. (I realized I had forgotten about this patch while reviewing my opened bugs)