[Bug 1415917] [NEW] Hardware watchpoints not working on ppc64le guests running on Ubuntu 14.10 host

[Launchpad Bug Tracker]

You have been subscribed to a public bug:

== Comment: #0 - Edjunior Barbosa Machado <emachado at br.ibm.com> - 2015-01-26 06:38:42 ==
GDB hw watchpoints don't work on ppc64le VMs running on top of Ubuntu 14.10 Power8 host (sid.ltc.br.ibm.com). It fails quietly, ptrace calls and dmesg output display no error message.

Tested on guests running different distros, kernel and  gdb versions
(distro's packages and upstream). Unfortunately, I couldn't find any
other Ubuntu 14.10 host to double check the problem, but it worked OK in
other hosts I've tried.

Steps to reproduce:

$ cat test.c 
int a;
main(void)
{
a++;
}

$ gcc -g test.c -o test

$ gdb ./test 
GNU gdb (Ubuntu 7.8.1-1ubuntu2) 7.8.1
...
Reading symbols from ./test...done.
(gdb) watch a
Hardware watchpoint 1: a
(gdb) run
Starting program: /home/emachado/test 
[Inferior 1 (process 8179) exited with code 0134]
(gdb) 

Curiously, in the host it works as expected:

$ gdb ./test 
GNU gdb (Ubuntu 7.8-1ubuntu4) 7.8.0.20141001-cvs
...
Reading symbols from ./test...done.
(gdb) watch a
Hardware watchpoint 1: a
(gdb) r
Starting program: /home/emachado/test 
Hardware watchpoint 1: a

Old value = 0
New value = 1
main () at test.c:5
5       }
(gdb)

** Affects: gdb (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: architecture-ppc64 bot-comment bugnameltc-120862 severity-high targetmilestone-inin---
-- 
Hardware watchpoints not working on ppc64le guests running on Ubuntu 14.10 host
https://bugs.launchpad.net/bugs/1415917
You received this bug notification because you are a member of Ubuntu Foundations Bugs, which is subscribed to gdb in Ubuntu.