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27f9f64975
The test introduced by this patch would fail in this configuration, with
the native-gdbserver or native-extended-gdbserver boards:
FAIL: gdb.threads/next-fork-other-thread.exp: fork_func=fork: target-non-stop=auto: non-stop=off: displaced-stepping=auto: i=2: next to for loop
The problem is that the step operation is forgotten when handling the
fork/vfork. With "debug infrun" and "debug remote", it looks like this
(some lines omitted for brevity). We do the next:
[infrun] proceed: enter
[infrun] proceed: addr=0xffffffffffffffff, signal=GDB_SIGNAL_DEFAULT
[infrun] resume_1: step=1, signal=GDB_SIGNAL_0, trap_expected=0, current thread [4154304.4154304.0] at 0x5555555553bf
[infrun] do_target_resume: resume_ptid=4154304.0.0, step=1, sig=GDB_SIGNAL_0
[remote] Sending packet: $vCont;r5555555553bf,5555555553c4:p3f63c0.3f63c0;c:p3f63c0.-1#cd
[infrun] proceed: exit
We then handle a fork event:
[infrun] fetch_inferior_event: enter
[remote] wait: enter
[remote] Packet received: T05fork:p3f63ee.3f63ee;06:0100000000000000;07:b08e59f6ff7f0000;10:bf60e8f7ff7f0000;thread:p3f63c0.3f63c6;core:17;
[remote] wait: exit
[infrun] print_target_wait_results: target_wait (-1.0.0 [process -1], status) =
[infrun] print_target_wait_results: 4154304.4154310.0 [Thread 4154304.4154310],
[infrun] print_target_wait_results: status->kind = FORKED, child_ptid = 4154350.4154350.0
[infrun] handle_inferior_event: status->kind = FORKED, child_ptid = 4154350.4154350.0
[remote] Sending packet: $D;3f63ee#4b
[infrun] resume_1: step=0, signal=GDB_SIGNAL_0, trap_expected=0, current thread [4154304.4154310.0] at 0x7ffff7e860bf
[infrun] do_target_resume: resume_ptid=4154304.0.0, step=0, sig=GDB_SIGNAL_0
[remote] Sending packet: $vCont;c:p3f63c0.-1#73
[infrun] fetch_inferior_event: exit
In the first snippet, we resume the stepping thread with the range-stepping (r)
vCont command. But after handling the fork (detaching the fork child), we
resumed the whole process freely. The stepping thread, which was paused by
GDBserver while reporting the fork event, was therefore resumed freely, instead
of confined to the addresses of the stepped line. Note that since this
is a "next", it could be that we have entered a function, installed a
step-resume breakpoint, and it's ok to continue freely the stepping
thread, but that's not the case here. The two snippets shown above were
next to each other in the logs.
For the fork case, we can resume stepping right after handling the
event.
However, for the vfork case, where we are waiting for the
external child process to exec or exit, we only resume the thread that
called vfork, and keep the others stopped (see patch "gdb: fix handling of
vfork by multi-threaded program" prior in this series). So we can't
resume the stepping thread right now. Instead, do it after handling the
vfork-done event.
Change-Id: I92539c970397ce880110e039fe92b87480f816bd
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.