RE: [off-list] Regressions introduced by MPX bound table patch

RE: [off-list] Regressions introduced by MPX bound table patch

[Tedeschi, Walfred]

Keith,

I will investigate that by today and tomorrow. Those days we had other issues here, I couldn't follow up on the list.

Thanks for the heads up! 

Best regards,
-Fred

-----Original Message-----
From: Keith Seitz [mailto:keiths@redhat.com] 
Sent: Wednesday, June 24, 2015 8:01 PM
To: Tedeschi, Walfred
Subject: [off-list] Regressions introduced by MPX bound table patch

Hi,

I don't know if you've followed gdb-patches in the last day or so, but with 7.10 branching soon, people are starting to investigate regressions.

The following commit introduced a regression:

  commit 29c1c24429a099eca297080dba56a8c090e3136a
  Author: Walfred Tedeschi <walfred.tedeschi@intel.com>
  Date:   Tue Jun 9 15:27:02 2015 +0200

      Add support for bound table in the Intel MPX context.
  [snip]

The problem is that when this feature is not supported, i386_mpx_info_bounds calls error(). This has the unfortunate side effect of aborting the call to "info set" tested in default.exp:

(gdb) info set
[snip]
mipsfpu:  The MIPS floating-point coprocessor is unknown because the current architecture is not MIPS.
monitor-prompt:  The prompt that GDB expects from the monitor is "".
monitor-warnings:  Printing of monitor warnings is 0.
mpx bound:  Intel(R) Memory Protection Extensions not supported on this target.
(gdb)

As you can see, "mpx bound" truncated the output, which should end:
[snip]
user:  verbose:  Verbosity is off.
watchdog:  Watchdog timer is 0.
width:  Number of characters gdb thinks are in a line is 80.
write:  Writing into executable and core files is off.
(gdb)

There is further discussion/proposals in the thread:
https://sourceware.org/ml/gdb-patches/2015-06/msg00495.html

Keith
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