mirror of
https://sourceware.org/git/binutils-gdb.git
synced 2025-02-05 12:53:16 +08:00
b0083dd72f
A following patch will add a testcase that has two processes with threads stepping over a breakpoint continuously, and then detaches from one of the processes while threads are running. The other process continues stepping over its breakpoint. And then the testcase sends a SIGUSR1, expecting that GDB reports it. That would sometimes hang against gdbserver, due to the bugs fixed here. Both bugs are related, in that they're about remote protocol asynchronous Stop notifications. There's a bug in GDB, and another in GDBserver. The GDB bug: - when we detach from a process, the remote target discards any pending RSP notification related to that process, including the in-flight, yet-unacked notification. Discarding the in-flight notification is the problem. Until the in-flight notification is acked with a vStopped packet, the server won't send another %Stop notification. As a result, the debug session gets messed up. In the new testcase's case, GDB would hang inside stop_all_threads, waiting for a stop for one of the process'es threads, which never arrived -- its stop reply was permanently stuck in the stop reply queue, waiting for a vStopped packet that never arrived. In summary: 1. GDBserver sends stop notification about thread X, the remote target receives it and stores it 2. At the same time, GDB detaches thread X's inferior 3. The remote target discards the received stop notification 4. GDBserver waits forever for the ack The GDBserver bug: GDBserver has the opposite bug. It also discards notifications for the process being detached. If that discards the head of the notification queue, when gdb sends an ack, it ends up acking the _next_ notification. Meaning, gdb loses one notification. In the testcase, this results in a similar hang in stop_all_threads. So we have two very similar bugs in GDB and GDBserver, both resulting in a similar symptom. That's why I'm fixing them both at the same time. gdb/ChangeLog: * remote.c (remote_notif_stop_ack): Don't error out on TARGET_WAITKIND_IGNORE; instead, just ignore the notification. (remote_target::discard_pending_stop_replies): Don't delete in-flight notification; instead, clear its contents. gdbserver/ChangeLog: * server.cc (discard_queued_stop_replies): Don't ever discard the notification at the head of the list. |
||
---|---|---|
bfd | ||
binutils | ||
config | ||
contrib | ||
cpu | ||
elfcpp | ||
etc | ||
gas | ||
gdb | ||
gdbserver | ||
gdbsupport | ||
gnulib | ||
gold | ||
gprof | ||
include | ||
intl | ||
ld | ||
libctf | ||
libdecnumber | ||
libiberty | ||
opcodes | ||
readline | ||
sim | ||
texinfo | ||
zlib | ||
.cvsignore | ||
.gitattributes | ||
.gitignore | ||
ar-lib | ||
ChangeLog | ||
compile | ||
config-ml.in | ||
config.guess | ||
config.rpath | ||
config.sub | ||
configure | ||
configure.ac | ||
COPYING | ||
COPYING3 | ||
COPYING3.LIB | ||
COPYING.LIB | ||
COPYING.LIBGLOSS | ||
COPYING.NEWLIB | ||
depcomp | ||
djunpack.bat | ||
install-sh | ||
libtool.m4 | ||
lt~obsolete.m4 | ||
ltgcc.m4 | ||
ltmain.sh | ||
ltoptions.m4 | ||
ltsugar.m4 | ||
ltversion.m4 | ||
MAINTAINERS | ||
Makefile.def | ||
Makefile.in | ||
Makefile.tpl | ||
makefile.vms | ||
missing | ||
mkdep | ||
mkinstalldirs | ||
move-if-change | ||
multilib.am | ||
README | ||
README-maintainer-mode | ||
setup.com | ||
src-release.sh | ||
symlink-tree | ||
test-driver | ||
ylwrap |
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.