binutils-gdb/gdb/testsuite/gdb.arch/ppc64-symtab-cordic.exp
Jan Kratochvil 80c570537e SEGV in ppc64_elf_get_synthetic_symtab reading a separate debug file
The attached patch fixes the SEGV and lets GDB successfully
load all kernel modules installed by default on RHEL 7.

Valgrind on F-21 x86_64 host has shown me more clear what is the problem:

Reading symbols from /home/jkratoch/t/cordic.ko...Reading symbols from
/home/jkratoch/t/cordic.ko.debug...=================================================================
==22763==ERROR: AddressSanitizer: heap-use-after-free on address 0x6120000461c8 at pc 0x150cdbd bp 0x7fffffffc7e0 sp 0x7fffffffc7d0
READ of size 8 at 0x6120000461c8 thread T0
    #0 0x150cdbc in ppc64_elf_get_synthetic_symtab /home/jkratoch/redhat/gdb-test-asan/bfd/elf64-ppc.c:3282
    #1 0x8c5274 in elf_read_minimal_symbols /home/jkratoch/redhat/gdb-test-asan/gdb/elfread.c:1205
    #2 0x8c55e7 in elf_symfile_read /home/jkratoch/redhat/gdb-test-asan/gdb/elfread.c:1268
[...]
0x6120000461c8 is located 264 bytes inside of 288-byte region [0x6120000460c0,0x6120000461e0)
freed by thread T0 here:
    #0 0x7ffff715454f in __interceptor_free (/lib64/libasan.so.1+0x5754f)
    #1 0xde9cde in xfree common/common-utils.c:98
    #2 0x9a04f7 in do_my_cleanups common/cleanups.c:155
    #3 0x9a05d3 in do_cleanups common/cleanups.c:177
    #4 0x8c538a in elf_read_minimal_symbols /home/jkratoch/redhat/gdb-test-asan/gdb/elfread.c:1229
    #5 0x8c55e7 in elf_symfile_read /home/jkratoch/redhat/gdb-test-asan/gdb/elfread.c:1268
[...]
previously allocated by thread T0 here:
    #0 0x7ffff71547c7 in malloc (/lib64/libasan.so.1+0x577c7)
    #1 0xde9b95 in xmalloc common/common-utils.c:41
    #2 0x8c4da2 in elf_read_minimal_symbols /home/jkratoch/redhat/gdb-test-asan/gdb/elfread.c:1147
    #3 0x8c55e7 in elf_symfile_read /home/jkratoch/redhat/gdb-test-asan/gdb/elfread.c:1268
[...]
SUMMARY: AddressSanitizer: heap-use-after-free /home/jkratoch/redhat/gdb-test-asan/bfd/elf64-ppc.c:3282 ppc64_elf_get_synthetic_symtab
[...]
==22763==ABORTING

A similar case a few lines later I have fixed in 2010 by:
        https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=3f1eff0a2c7f0e7078f011f55b8e7f710aae0cc2

My testcase does not always reproduce it but at least a bit:
 * GDB without ppc64 target (even as a secondary one) is reported as "untested"
 * ASAN-built GDB with ppc64 target always crashes (and PASSes with this fix)
 * unpatched non-ASAN-built GDB with ppc64 target crashes from commandline
 * unpatched non-ASAN-built GDB with ppc64 target PASSes from runtest (?)

gdb/ChangeLog
2015-02-26  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* elfread.c (elf_read_minimal_symbols): Use bfd_alloc for
	bfd_canonicalize_symtab.

gdb/testsuite/ChangeLog
2015-02-26  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.arch/cordic.ko.bz2: New file.
	* gdb.arch/cordic.ko.debug.bz2: New file.
	* gdb.arch/ppc64-symtab-cordic.exp: New file.
2015-02-26 14:08:01 +01:00

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# Copyright 2015 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 <http://www.gnu.org/licenses/>.
standard_testfile
set kobz2file ${srcdir}/${subdir}/cordic.ko.bz2
set kofile ${objdir}/${subdir}/cordic.ko
set kodebugbz2file ${srcdir}/${subdir}/cordic.ko.debug.bz2
set kodebugfile ${objdir}/${subdir}/cordic.ko.debug
if {[catch "system \"bzip2 -dc ${kobz2file} >${kofile}\""] != 0} {
untested "failed bzip2 for ${kobz2file}"
return -1
}
if {[catch "system \"bzip2 -dc ${kodebugbz2file} >${kodebugfile}\""] != 0} {
untested "failed bzip2 for ${kodebugbz2file}"
return -1
}
gdb_exit
gdb_start
gdb_reinitialize_dir $srcdir/$subdir
# This test won't work properly if system debuginfo is installed.
# Test message is suppressed by "" as otherwise we could print PASS+UNTESTED
# result to gdb.sum making a false feeling the issue has been tested.
gdb_test_no_output "set debug-file-directory" ""
gdb_load ${kofile}
set test "show architecture"
gdb_test_multiple $test $test {
-re "\r\nThe target architecture is set automatically \\(currently powerpc:common64\\)\r\n$gdb_prompt $" {
pass $test
}
-re "\r\nThe target architecture is set automatically \\(currently .*\\)\r\n$gdb_prompt $" {
untested "powerpc:common64 is not supported"
}
}