From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by sourceware.org (Postfix) with ESMTPS id 90B3E38930F4 for ; Wed, 17 Jun 2020 16:22:15 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 90B3E38930F4 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=tdevries@suse.de X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id B7E87B06B; Wed, 17 Jun 2020 16:22:18 +0000 (UTC) Subject: Re: [PATCH] gdb: check for partial symtab presence in dwarf2_initialize_objfile To: Simon Marchi , gdb-patches@sourceware.org Cc: Tom Tromey References: <20200612214454.1896242-1-simon.marchi@efficios.com> From: Tom de Vries Autocrypt: addr=tdevries@suse.de; keydata= xsBNBF0ltCcBCADDhsUnMMdEXiHFfqJdXeRvgqSEUxLCy/pHek88ALuFnPTICTwkf4g7uSR7 HvOFUoUyu8oP5mNb4VZHy3Xy8KRZGaQuaOHNhZAT1xaVo6kxjswUi3vYgGJhFMiLuIHdApoc u5f7UbV+egYVxmkvVLSqsVD4pUgHeSoAcIlm3blZ1sDKviJCwaHxDQkVmSsGXImaAU+ViJ5l CwkvyiiIifWD2SoOuFexZyZ7RUddLosgsO0npVUYbl6dEMq2a5ijGF6/rBs1m3nAoIgpXk6P TCKlSWVW6OCneTaKM5C387972qREtiArTakRQIpvDJuiR2soGfdeJ6igGA1FZjU+IsM5ABEB AAHNH1RvbSBkZSBWcmllcyA8dGRldnJpZXNAc3VzZS5kZT7CwKsEEwEIAD4WIQSsnSe5hKbL MK1mGmjuhV2rbOJEoAUCXSW0JwIbAwUJA8JnAAULCQgHAgYVCgkICwIEFgIDAQIeAQIXgAAh CRDuhV2rbOJEoBYhBKydJ7mEpsswrWYaaO6FXats4kSgc48H/Ra2lq5p3dHsrlQLqM7N68Fo eRDf3PMevXyMlrCYDGLVncQwMw3O/AkousktXKQ42DPJh65zoXB22yUt8m0g12xkLax98KFJ 5NyUloa6HflLl+wQL/uZjIdNUQaHQLw3HKwRMVi4l0/Jh/TygYG1Dtm8I4o708JS4y8GQxoQ UL0z1OM9hyM3gI2WVTTyprsBHy2EjMOu/2Xpod95pF8f90zBLajy6qXEnxlcsqreMaqmkzKn 3KTZpWRxNAS/IH3FbGQ+3RpWkNGSJpwfEMVCeyK5a1n7yt1podd1ajY5mA1jcaUmGppqx827 8TqyteNe1B/pbiUt2L/WhnTgW1NC1QDOwE0EXSW0JwEIAM99H34Bu4MKM7HDJVt864MXbx7B 1M93wVlpJ7Uq+XDFD0A0hIal028j+h6jA6bhzWto4RUfDl/9mn1StngNVFovvwtfzbamp6+W pKHZm9X5YvlIwCx131kTxCNDcF+/adRW4n8CU3pZWYmNVqhMUiPLxElA6QhXTtVBh1RkjCZQ Kmbd1szvcOfaD8s+tJABJzNZsmO2hVuFwkDrRN8Jgrh92a+yHQPd9+RybW2l7sJv26nkUH5Z 5s84P6894ebgimcprJdAkjJTgprl1nhgvptU5M9Uv85Pferoh2groQEAtRPlCGrZ2/2qVNe9 XJfSYbiyedvApWcJs5DOByTaKkcAEQEAAcLAkwQYAQgAJhYhBKydJ7mEpsswrWYaaO6FXats 4kSgBQJdJbQnAhsMBQkDwmcAACEJEO6FXats4kSgFiEErJ0nuYSmyzCtZhpo7oVdq2ziRKD3 twf7BAQBZ8TqR812zKAD7biOnWIJ0McV72PFBxmLIHp24UVe0ZogtYMxSWKLg3csh0yLVwc7 H3vldzJ9AoK3Qxp0Q6K/rDOeUy3HMqewQGcqrsRRh0NXDIQk5CgSrZslPe47qIbe3O7ik/MC q31FNIAQJPmKXX25B115MMzkSKlv4udfx7KdyxHrTSkwWZArLQiEZj5KG4cCKhIoMygPTA3U yGaIvI/BGOtHZ7bEBVUCFDFfOWJ26IOCoPnSVUvKPEOH9dv+sNy7jyBsP5QxeTqwxC/1ZtNS DUCSFQjqA6bEGwM22dP8OUY6SC94x1G81A9/xbtm9LQxKm0EiDH8KBMLfQ== Message-ID: <01c28a5e-7b2b-5292-5e3d-c5880f8153b8@suse.de> Date: Wed, 17 Jun 2020 18:22:13 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <20200612214454.1896242-1-simon.marchi@efficios.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-15.7 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, KAM_SHORT, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 17 Jun 2020 16:22:17 -0000 On 6/12/20 11:44 PM, Simon Marchi wrote: > This patch fixes an internal error that is triggered when loading the > same binary twice with the index-cache on: > > $ ./gdb -q -nx --data-directory=data-directory > (gdb) set index-cache on > (gdb) shell mktemp -d > /tmp/tmp.BLgouVoPq4 > (gdb) set index-cache directory /tmp/tmp.BLgouVoPq4 > (gdb) file a.out > Reading symbols from a.out... > (gdb) file a.out > Load new symbol table from "a.out"? (y or n) y > Reading symbols from a.out... > /home/smarchi/src/binutils-gdb/gdb/dwarf2/read.c:2540: internal-error: void create_cus_from_index(dwarf2_per_bfd*, const gdb_byte*, offset_type, const gdb_byte*, offset_type): Assertion `per_bfd->all_comp_units.empty ()' failed. > A problem internal to GDB has been detected, > further debugging may prove unreliable. > Quit this debugging session? (y or n) > > This is what happens: > > 1. We load the binary the first time, partial symtabs are created, > per_bfd->all_comp_units is filled from those. > 2. Because index-cache is on, we also generate an index in the cache. > 3. We load the binary a second time, in dwarf2_initialize_objfile we > check: was an index already loaded for this BFD? No, so we try to > read the index and fill the per-bfd using it. We do find an index, > it's in the cache. > 4. The function create_cus_from_index asserts (rightfully) that > per_cu->all_comp_units is empty, and the assertion fails. > > This assertion verifies that we are not reading an index for a BFD for > which we have already built partial symtabs or read another index. > > The index-cache gives a situation that isn't currently accounted for: a > BFD for which we have built the partial symtabs the first time, but has > an index the second time. > > This patch addresses it by checking for the presence of partial symtabs > in dwarf2_initialize_objfile. If there are, we don't try reading the > index. > > gdb/ChangeLog: > > * dwarf2/read.c (dwarf2_initialize_objfile): Check for presence > of partial symtabs. > > gdb/testsuite/ChangeLog: > > * gdb.base/index-cache-load-twice.c: New. > * gdb.base/index-cache-load-twice.exp: New. > > Change-Id: Ie05474c44823fcdff852b73170dd28dfd66cb6a2 > --- > gdb/dwarf2/read.c | 8 ++++ > .../gdb.base/index-cache-load-twice.c | 22 ++++++++++ > .../gdb.base/index-cache-load-twice.exp | 42 +++++++++++++++++++ > 3 files changed, 72 insertions(+) > create mode 100644 gdb/testsuite/gdb.base/index-cache-load-twice.c > create mode 100644 gdb/testsuite/gdb.base/index-cache-load-twice.exp > > diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c > index e3073fe43ce3..a6b74ae4da6b 100644 > --- a/gdb/dwarf2/read.c > +++ b/gdb/dwarf2/read.c > @@ -6027,6 +6027,14 @@ dwarf2_initialize_objfile (struct objfile *objfile, dw_index_kind *index_kind) > return true; > } > > + /* There might already be partial symtabs built for this BFD. This happens > + when loading the same binary twice with the index-cache enabled. If so, > + don't try to read an index. The objfile / per_objfile initialization will > + be completed in dwarf2_build_psymtabs, in the standard partial symtabs > + code path. */ > + if (per_bfd->partial_symtabs != nullptr) > + return false; > + > if (dwarf2_read_debug_names (per_objfile)) > { > *index_kind = dw_index_kind::DEBUG_NAMES; > diff --git a/gdb/testsuite/gdb.base/index-cache-load-twice.c b/gdb/testsuite/gdb.base/index-cache-load-twice.c > new file mode 100644 > index 000000000000..9d7b2f1a4c28 > --- /dev/null > +++ b/gdb/testsuite/gdb.base/index-cache-load-twice.c > @@ -0,0 +1,22 @@ > +/* This testcase is part of GDB, the GNU debugger. > + > + Copyright 2020 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 . */ > + > +int > +main (void) > +{ > + return 0; > +} I wonder if this is generic enough to call main.c, and then perhaps we can start reusing that one. > diff --git a/gdb/testsuite/gdb.base/index-cache-load-twice.exp b/gdb/testsuite/gdb.base/index-cache-load-twice.exp > new file mode 100644 > index 000000000000..4d58097529b8 > --- /dev/null > +++ b/gdb/testsuite/gdb.base/index-cache-load-twice.exp > @@ -0,0 +1,42 @@ > +# Copyright 2020 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 test checks that loading a file twice with the index cache enabled does > +# not crash. > + > +standard_testfile > + > +lassign [remote_exec host mktemp -d] ret cache_dir > + > +# The output of mktemp contains an end of line, remote it. remote -> remove. > +set cache_dir [string trimright $cache_dir \r\n] > + > +if { $ret != 0 } { > + fail "couldn't create temporary cache dir" > + return > +} > + > +save_vars { GDBFLAGS } { > + set GDBFLAGS "$GDBFLAGS -iex \"set index-cache directory $cache_dir\"" > + set GDBFLAGS "$GDBFLAGS -iex \"set index-cache on\"" > + > + if { [prepare_for_testing "failed to prepare" $testfile $srcfile \ > + {debug additional_flags=-Wl,--build-id}] } { > + return > + } > + > + # This file command would generate an internal error. > + gdb_file_cmd [standard_output_file $testfile] > +} > LGTM otherwise. Thanks, - Tom