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Sergio Durigan Junior 685de8c299 Fix PR gdb/22491: Regression when setting SystemTap probe semaphores
Pedro has kindly pointed out that
gdb.arch/amd64-stap-optional-prefix.exp was failing after my
C++-ification patches touching the probe interface.  The failure is
kind of cryptic:

 77 break -pstap bar
 78 Breakpoint 3 at 0x40048d
 79 (gdb) PASS: gdb.arch/amd64-stap-optional-prefix.exp: bar: break -pstap bar
 80 continue
 81 Continuing.
 82
 83 Program received signal SIGILL, Illegal instruction.
 84 main () at amd64-stap-optional-prefix.S:26
 85 26              STAP_PROBE1(probe, foo, (%rsp))

It took me a while to figure out where this SIGILL is coming from.
Initially I thought it was something related to writing registers to
the inferior when dealing with probe arguments, but I discarded this
since the arguments were not touching any registers.

In the end, this was a mistake that was introduced during the review
process of the patch.  When setting/clearing a SystemTap probe's
semaphore, the code was using 'm_address' (which refers the probe's
address) instead of 'm_sem_addr' (which refers to the semaphore's
address).  This caused GDB to write a bogus value in the wrong memory
position, which in turn caused the SIGILL.

I am pushing this patch to correct the mistake.

On a side note: I told Pedro that the BuildBot hadn't caught the
failure during my try build, and for a moment there was a suspicion
that the BuildBot might be at fault here.  However, I investigate this
and noticed that I only did one try build, with a patch that was
correctly using 'm_sem_addr' where applicable, and therefore no
failure should have happened indeed.  I probably should have requested
another try build after addressing the review's comments, but they
were mostly basic and I didn't think it was needed.  Oh, well.

2017-11-25  Sergio Durigan Junior  <sergiodj@redhat.com>

	PR gdb/22491
	* stap-probe.c (relocate_address): New function.
	(stap_probe::get_relocated_address): Use 'relocate_address'.
	(stap_probe::set_semaphore): Use 'relocate_address' and pass
	'm_sem_addr'.
	(stap_probe::clear_semaphore): Likewise.
2017-11-25 01:13:03 -05:00
bfd Automatic date update in version.in 2017-11-25 00:00:26 +00:00
binutils Re-apply "elf: Properly compute offsets of note descriptor and next note" 2017-11-24 14:52:15 -08:00
config picflag.m4 high bit set in comment 2017-01-05 00:02:57 +10:30
cpu Update the openrisc previous program counter (ppc) when running code in the cgen based simulator. 2017-03-20 15:33:51 +00:00
elfcpp oops - changelog entry omitted from previous delta 2017-09-21 09:07:11 +01:00
etc update-copyright.py for binutils 2017-01-05 00:03:07 +10:30
gas Add reference to implicit use in _bfd_elf_is_local_label_name. 2017-11-24 09:31:59 -08:00
gdb Fix PR gdb/22491: Regression when setting SystemTap probe semaphores 2017-11-25 01:13:03 -05:00
gold Fix typo in ChangeLog entry. 2017-11-19 18:02:31 -08:00
gprof Update the Hungarian translation in the gprof directory. 2017-10-05 14:10:27 +01:00
include Re-apply "elf: Properly compute offsets of note descriptor and next note" 2017-11-24 14:52:15 -08:00
intl Require ngettext in test of system gettext implementation 2017-11-07 15:56:44 +10:30
ld Update PR ld/21562 tests for underscore targets 2017-11-24 08:58:56 -08:00
libdecnumber
libiberty Sync libiberty/ & include/ with GCC 2017-09-15 17:40:33 +01:00
opcodes x86: don't omit disambiguating suffixes from "fi*" 2017-11-24 08:42:04 +01:00
readline Avoid MinGW compilation warning in readline/input.c 2017-05-19 11:05:59 +03:00
sim FT32: support for FT32B processor - part 2/2 2017-11-01 18:36:51 -07:00
texinfo
zlib Sync ZLIB with FSF GCC sources, bringing in version 1.2.11. 2017-02-20 12:52:22 +00:00
.cvsignore
.gitattributes
.gitignore Add archives and make stamps to the .gitignore file. 2016-09-27 15:10:42 +01:00
ChangeLog Add -l option to src-release script. 2017-09-15 16:18:20 +01:00
compile
config-ml.in
config.guess Sync top level config files with master versions in the FSF config project. 2017-03-22 14:01:03 +00:00
config.rpath
config.sub * config.sub: Sync with master version in config project. 2017-04-13 02:34:19 -07:00
configure Sync top-level make and configure files with FSF GCC mainline versions. 2017-01-23 11:55:48 +00:00
configure.ac Sync top-level make and configure files with FSF GCC mainline versions. 2017-01-23 11:55:48 +00:00
COPYING
COPYING.LIB
COPYING.LIBGLOSS
COPYING.NEWLIB
COPYING3
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depcomp
djunpack.bat
install-sh
libtool.m4
ltgcc.m4
ltmain.sh
ltoptions.m4
ltsugar.m4
ltversion.m4
lt~obsolete.m4
MAINTAINERS
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Makefile.in Sync top-level make and configure files with FSF GCC mainline versions. 2017-01-23 11:55:48 +00:00
Makefile.tpl Sync top-level make and configure files with FSF GCC mainline versions. 2017-01-23 11:55:48 +00:00
makefile.vms
missing
mkdep
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README
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src-release.sh Add -l option to src-release script. 2017-09-15 16:18:20 +01:00
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		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
and OS.)

If you have more than one compiler on your system, it is often best to
explicitly set CC in the environment before running configure, and to
also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

Much of the code and documentation enclosed is copyright by
the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
GNU General Public License terms under which you can copy the files.

REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.