This applies the second part of GDB's End of Year Procedure, which
updates the copyright year range in all of GDB's files.
gdb/ChangeLog:
Update copyright year range in all GDB files.
Loading a core dump that was either generated on a system running
pristine glibc master, or on a Fedora/RHEL system with LD_DEBUG=unused
set in the environment, solib-svr4.c:svr4_current_sos fails to filter
out the vDSO, resulting in:
(gdb) core-file corefile.core^M
[New LWP 2362]^M
warning: Could not load shared library symbols for linux-vdso.so.1.^M
Do you need "set solib-search-path" or "set sysroot"?^M
Core was generated by `build-gdb/gdb/testsuite/outputs/gdb.base/corefile/'.^M
...
The problem is that gdbarch_vsyscall_range does not support core
inferiors at all.
When live debugging, we're finding the vDSO's start address with
auxv/AT_SYSINFO_EHDR, and then we find the vDSO's size by look for the
corresponding mapping, by parsing /proc/PID/maps. When debugging a
core dump, we can also determine the starting address from
auxv/AT_SYSINFO_EHDR. However, we obviously can't read the core
mappings out of the host's /proc. But we can instead look for a
corresponding load segment in the core's bfd.
gdb/ChangeLog:
2016-08-22 Pedro Alves <palves@redhat.com>
PR gdb/20505
* linux-tdep.c (linux_vsyscall_range_raw): For core inferiors,
find the vDSO's start address with AT_SYSINFO_EHDR too, and
determine the vDSO's size by finding the PT_LOAD segment that
matches AT_SYSINFO_EHDR.
gdb/testsuite/ChangeLog:
2016-08-22 Pedro Alves <palves@redhat.com>
PR gdb/20505
* gdb.base/vdso-warning.exp: Test core dumps too. Use
with_test_prefix. Factor out bits to ...
(test_no_vdso): ... this new procedure.
With upstream glibc, GDB prints:
warning: Could not load shared library symbols for linux-vdso.so.1.
Do you need "set solib-search-path" or "set sysroot"?
A bug's been filed for glibc a few years back:
http://sourceware.org/bugzilla/show_bug.cgi?id=13097
but it's still not resolved. It's not clear whether there's even
consensus that this is indeed a glibc bug. It would actually be nice
if GDB also listed the vDSO in the shared library list, but there are
some design considerations with that:
- the vDSO is mapped by the kernel, not userspace, therefore we
should load its symbols right from the process's start of life,
even before glibc / the userspace loader sets up the initial DSO
list. The program might even be using a custom loader or no
loader.
- that kind of hints at that solib.c should handle retrieving shared
library lists from more than one source, and that symfile-mem.c's
loading of the vDSO would be converted to load and relocate the
vDSO's bfd behind the target_so_ops interface.
- and then, once glibc links in the vDSO to its DSO list, we'd need
to either:
a) somehow hand over the vDSO from one target_so_ops to the other
b) simply keep hiding glibc's entry.
And then b) seems the simplest.
With that in mind, this patch simply discards the vDSO from glibc's
reported shared library list.
We can match the vDSO address range with the addresses found iterating
the dynamic linker list, to tell which dynamic linker entry is the
vDSO.
Tested on x86_64 Fedora 20.
gdb/
2014-10-10 Jan Kratochvil <jan.kratochvil@redhat.com>
Pedro Alves <palves@redhat.com>
PR symtab/14466
* solib-svr4.c (svr4_read_so_list): Rename to ...
(svr4_current_sos_1): ... this and change the function comment.
(svr4_current_sos): New function.
gdb/testsuite/
2014-10-10 Jan Kratochvil <jan.kratochvil@redhat.com>
Pedro Alves <palves@redhat.com>
PR symtab/14466
* gdb.base/vdso-warning.c: New file.
* gdb.base/vdso-warning.exp: New file.
Joel Brobecker
Pedro Alves