Racy failures on gdb.base/gdbinit-history.exp (native-extended-gdbserver/-m64) (was: Re: [PATCH] Don't truncate the history file when history size is unlimited)

[Sergio Durigan Junior <sergiodj at redhat dot com>]

On Tuesday, June 16 2015, Patrick Palka wrote:

> We still do not handle "set history size unlimited" correctly.  In
> particular, after writing to the history file, we truncate the history
> even if it is unlimited.
>
> This patch makes sure that we do not call history_truncate_file() if the
> history is not stifled (i.e. if it's unlimited).  This bug causes the
> history file to be truncated to zero on exit when one has "set history
> size unlimited" in their gdbinit file.  Although this code exists in GDB
> 7.8, the bug is masked by a pre-existing bug that's been only fixed in
> GDB 7.9 (PR gdb/17820).

Hey Patrick,

Looking at the BuildBot logs today, I found that this new test is
failing occasionally on native-extended-gdbserver testing.  Take a look
at the following build:

  <http://gdb-build.sergiodj.net/builders/Debian-x86_64-native-extended-gdbserver-m64/builds/1429>

You can see that gdb.base/gdbinit-history.exp failed:

  PASS -> FAIL: gdb.base/gdbinit-history.exp: truncation: appending: server show commands
  PASS -> FAIL: gdb.base/gdbinit-history.exp: truncation: creating: server show commands

The gdb.log is here:

  <http://gdb-build.sergiodj.net/cgit/Debian-x86_64-native-extended-gdbserver-m64/.git/plain/gdb.log?id=2abe37b834f73838c68e1f843bdd612cef4a2ae3>

I haven't really investigated to determine what's going on here, but let
me know if you need any help with this.

Thanks,

-- 
Sergio
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