From patchwork Fri Dec 5 20:32:48 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Simon Marchi X-Patchwork-Id: 4097 Received: (qmail 16240 invoked by alias); 5 Dec 2014 20:32:54 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 16230 invoked by uid 89); 5 Dec 2014 20:32:54 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No 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: usevmg21.ericsson.net Received: from usevmg21.ericsson.net (HELO usevmg21.ericsson.net) (198.24.6.65) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-SHA encrypted) ESMTPS; Fri, 05 Dec 2014 20:32:52 +0000 Received: from EUSAAHC002.ericsson.se (Unknown_Domain [147.117.188.78]) by usevmg21.ericsson.net (Symantec Mail Security) with SMTP id 13.C3.25146.F1AB1845; Fri, 5 Dec 2014 14:58:56 +0100 (CET) Received: from [142.133.110.254] (147.117.188.8) by smtps-am.internal.ericsson.com (147.117.188.78) with Microsoft SMTP Server (TLS) id 14.3.195.1; Fri, 5 Dec 2014 15:32:49 -0500 Message-ID: <54821670.6020006@ericsson.com> Date: Fri, 5 Dec 2014 15:32:48 -0500 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> In-Reply-To: <54809E38.3080606@redhat.com> X-IsSubscribed: yes 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;