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On some heavily loaded AArch64 boxes, GDB will sometimes hang forever when the inferior creates a thread. This hang happens inside the kernel during the ptrace call to set hardware watchpoints or hardware breakpoints. Currently, GDB will always set hw wp/bp at the start of each thread even if there are none set in the process. This patch works around the issue by avoiding setting hw wp/bp if there are none set for the process. On an effected machine, this fix drastically reduces the racy nature of the gdb.threads test set. I ran the entire gdb test suite across all processors for 100 iterations, then ran the results through the racy tests script. Without the patch, 58 .exp files in gdb.threads were marked as racy. After the patch this reduced to the same ~14 tests as the non effected boxes. Clearly GDB will still be subject to hangs on an effect box if hw wp/bp's are used prior to creating inferior threads on a heavily loaded system. To enable this in gdbserver, the sequence in gdbserver add_lwp() is switched to the same as gdb order as gdb, to ensure the thread is registered before calling new_thread(). This allows aarch64_linux_new_thread() to read the ptid. gdb/ChangeLog: * nat/aarch64-linux-hw-point.c (aarch64_linux_any_set_debug_regs_state): New function. * nat/aarch64-linux-hw-point.h (aarch64_linux_any_set_debug_regs_state): New declaration. * nat/aarch64-linux.c (aarch64_linux_new_thread): Check if any BPs or WPs are set. gdb/gdbserver/ChangeLog: * linux-low.c (add_lwp): Switch ordering.
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.