Red Hat Bugzilla – Bug 437970
ppc kernel hardware watchpoint support
Last modified: 2013-03-07 19:55:59 EST
Description of problem:
There was a request for GDB (Bug 253117) to support hardware watchpoints in
But it still does not (reliably) work as it is broken even upstream.
No one knows if it is a kernel or hardware problem.
Version-Release number of selected component (if applicable):
Not found the right kernel/RHEL-5 combo machine in RH.
All the Fedora kernels (such as kernel-2.6.25-0.121.rc5.git4.fc9.ppc64).
All the upstream kernels.
99% of runs with enough (>16) threads (set by THREADS).
Steps to Reproduce:
1. wget -O ppc-dabr-race.c
2. gcc -o ppc-dabr-race ppc-dabr-race.c -Wall -ggdb2 -m32 -D_GNU_SOURCE -pthread
3. ./ppc-dabr-race ;echo $?
Tested on: ppc03.englab.brq.redhat.com
cpu : POWER5 (gr)
clock : 1502.496000MHz
revision : 2.2 (pvr 003a 0202)
Compile with -DDEBUG to see why it fails.
It was discussed upstream with IBM, mail threads at:
-m64 has the same error as -m32.
Return code 77 means the kernel/CPU combo does not support hardware watchpoints.
See upstream commit a2ceff5e555e664751bc653a4d9b133efa18c742,
seems to have fixed it.
Created attachment 299586 [details]
This request was evaluated by Red Hat Product Management for
inclusion, but this component is not scheduled to be updated in
the current Red Hat Enterprise Linux release. If you would like
this request to be reviewed for the next minor release, ask your
support representative to set the next rhel-x.y flag to "?".
Unfortunately the previous automated notification about the
non-inclusion of this request in Red Hat Enterprise Linux 5.3 used
the wrong text template. It should have read: this request has been
reviewed by Product Management and is not planned for inclusion
in the current minor release of Red Hat Enterprise Linux.
If you would like this request to be reviewed for the next minor
release, ask your support representative to set the next rhel-x.y
flag to "?" or raise an exception.
I tested this on the *.128 kernel for RHEL5.3 and the test case passed.
[root@ibm-p5-185-01 ~]# uname -a
Linux ibm-p5-185-01.rhts.bos.redhat.com 2.6.18-128.el5 #1 SMP Wed Dec 17 11:58:23 EST 2008 ppc64 ppc64 ppc64 GNU/Linux
Test case results:
[root@ibm-p5-185-01 ~]# ./ppc-dabr-race ;echo $?
If there are no objections, I would like to close this as fixed in the latest release. I'll wait until Friday, 2/20 for a response.
*** This bug has been marked as a duplicate of bug 444076 ***
As Bug 444076 is not public, it should (with no guarantees) be found in RHEL-5.3:
- [ppc64] missed hw breakpoints across multiple threads (Brad Peters )