PR gdb/17968 - [ppc64] SEGV in ppc64_elf_get_synthetic_symtab reading a separate debug file
Commit Message
The attached patch fixes the SEGV and lets GDB successfully
load all kernel modules installed by default on RHEL 7. GDB
still aborts when attempting to list functions in many of
the modules but that's a separate problem (bug #17993).
The patch has been tested on ppc64 with the results below.
=== gdb Summary ===
PATCHED unpatched
# of expected passes 29991 29989
# of unexpected failures 103 103
# of unexpected successes 1 1
# of expected failures 67 67
# of known failures 54 54
# of untested testcases 32 32
# of unsupported tests 190 190
Martin
@@ -1,3 +1,9 @@
+2015-02-16 Martin Sebor <msebor@redhat.com>
+
+ PR gdb/17968
+ * elread.c (elf_symfile_read): Use synth_abfd only for shared and
+ executable objects (but not relocatable files).
+
2015-02-13 Doug Evans <dje@google.com>
* cp-namespace.c (cp_basic_lookup_symbol): Rename parameter
@@ -1183,19 +1183,22 @@ elf_read_minimal_symbols (struct objfile *objfile, int symfile_flags,
elf_rel_plt_read (objfile, dyn_symbol_table);
}
- /* Contrary to binutils --strip-debug/--only-keep-debug the strip command from
- elfutils (eu-strip) moves even the .symtab section into the .debug file.
+ /* Both the Binutils strip command and the Elfutils eu-strip command
+ remove the .symtab section from executables or dynamic object files
+ (but not from reloacatable object files like Linux kernel modules)
+ and move it into the .debug file.
bfd_get_synthetic_symtab on ppc64 for each function descriptor ELF symbol
'name' creates a new BSF_SYNTHETIC ELF symbol '.name' with its code
- address. But with eu-strip files bfd_get_synthetic_symtab would fail to
- read the code address from .opd while it reads the .symtab section from
- a separate debug info file as the .opd section is SHT_NOBITS there.
+ address. But with stripped files without the .symtab section
+ bfd_get_synthetic_symtab would fail to read the code address from .opd
+ while it reads the .symtab section from a separate debug info file as
+ the .opd section is SHT_NOBITS there.
With SYNTH_ABFD the .opd section will be read from the original
backlinked binary where it is valid. */
- if (objfile->separate_debug_objfile_backlink)
+if (abfd->flags & (EXEC_P | DYNAMIC) && objfile->separate_debug_objfile_backlink)
synth_abfd = objfile->separate_debug_objfile_backlink->obfd;
else
synth_abfd = abfd;
@@ -1,3 +1,9 @@
+2015-02-16 Martin Sebor <msebor@redhat.com>
+
+ PR gdb/17968
+ * gdb.base/strip-relocatable.c: New file.
+ * gdb.base/strip-relocatable.exp: New file.
+
2015-02-11 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.python/py-framefilter.exp (pagination quit - *): New tests.
new file mode 100644
@@ -0,0 +1,3 @@
+void foo (void) __attribute__ ((section (".bar")));
+void foo (void) { }
+
new file mode 100644
@@ -0,0 +1,87 @@
+# Copyright (C) 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
+
+# Full pathname of the test source file.
+set srcpath ${srcdir}/${subdir}/$srcfile
+
+# Full pathname of the linker script.
+set ldspath ${srcdir}/${subdir}/[file rootname $srcfile].lds
+
+# Compile only with debugging.
+if {[target_compile $srcpath $binfile.o object debug] != ""} then {
+ untested ${testfile}.exp
+ return -1
+}
+
+# Invoke the linker to create a relocatable file for Binutils testing.
+if {[target_link $binfile.o $binfile.bu "--build-id -r -T $ldspath"] != ""} then {
+ untested $testfile.exp
+ return -1
+}
+
+# Verify that a command succeeded. Returns 1 on success, 0 on failure.
+proc verify { command } {
+ set status [catch {remote_exec build $command} -1]
+ if {[lindex $status 0] != 0} {
+ return 0
+ }
+ return 1
+}
+
+# Create a copy of the relocatable file for Elfutils testing.
+verify "cp $binfile.bu $binfile.eu"
+
+# Verify that GDB can read symbols from a relocatable file stripped
+# using Binutils strip and objcopy commands.
+set test "relocatable file stripped using Binutils"
+
+if { [# Copy debug info from the relocatable file into a separate .dbg file.
+ verify "objcopy --only-keep-debug $binfile.bu $binfile.bu.dbg"] &&
+ [# Strip debug (and other unneeded) sections from the relocatable
+ # file.
+ verify "strip --strip-debug --strip-unneeded $binfile.bu"] &&
+ [# Insert the .gnu_debuglink section into the relocatable file
+ # pointing at the separate .dbg file.
+ verify "objcopy --add-gnu-debuglink $binfile.bu.dbg $binfile.bu"]} {
+
+ # Restart the debugger with the relocatable file as an operand.
+ clean_restart $binfile.bu
+
+ # Print the type of the function foo defined in the test file
+ # and verify that it has the expected type.
+ gdb_test "ptype foo" "type = void \\(void\\)" \
+ "symbols in a Binutils-stripped file"
+}
+
+
+# Repeat the same test as above but with Elfutils. I.e., verify
+# that GDB can read symbols from a relocatable file stripped using
+# the Eflutils eu-strip command.
+set test "relocatable file stripped using Elfutils"
+
+# Use eu-strip to strip debug info from the relocatable file
+# and move it into a separate .dbg file in one step.
+if {[verify "eu-strip -f $binfile.eu.dbg $binfile.eu" ]} {
+
+ # Restart the debugger with the relocatable file as an operand.
+ clean_restart $testfile.eu
+
+ # Print the type of the function foo defined in the test file
+ # and verify that it has the expected type.
+ gdb_test "ptype foo" "type = void \\(void\\)" \
+ "symbols in an Elfutils-stripped file"
+}