[PATCH 0/2] Native follow-exec-mode cleanup
Tue Aug 25 22:41:00 GMT 2015
This patchset implements a test for follow-exec-mode and addresses
several failures in the native implementation of follow-exec-mode.
I submitted a patchset several weeks ago that purported to implement
exec events and follow-exec-mode for extended-remote Linux targets
That had an issue with one of the follow-exec-mode cases. As part
of working on that I implemented a test for follow-exec-mode
(gdb.base/foll-exec.exp doesn't test follow-exec-mode, it only tests
exec event handling). When I ran the test against the native x64
Linux debugger, I found several failures. There was no point in
submitting updates to the extended-remote exec event patchset until
these issues had been dealt with.
First, if there is a breakpoint in the original program that doesn't
map to a location in the execd program (e.g. on a line number in a
file that doesn't exist in the execd program), GDB gets "Error in
After attempting a fix, I concluded that this error is benign, and
actually informative. It lets the user know that a breakpoint did
not survive across the exec. So I left this alone. Make sense?
Second, with follow-exec-mode == "new" and using 'next' across the
exec call, GDB segfaulted. Once that was fixed, there were a couple
of other issues to clean up.
Finally, I tried using 'next' across a call to exec after deleting
all breakpoints. In this case the execed program runs to completion.
In breakpoint.c:update_breakpoints_after_exec the comments make it
clear that this is not expected to work. It seems like it might be
possible to make such a thing work, but it's beyond the scope of
what I'm working on now.
So ultimately this patchset only implements the test and fixes the
Patch 1/2: Implement gdb.base/foll-exec-2.exp to test follow-exec-mode.
Patch 2/2: Fix native follow-exec-mode "new".
Tested all on native x86_64 Linux.
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