Many thanks to Christoph Lutz who kindly provided the workaround for the
problem: set _use_ism=false and _use_ism_for_pga=false .
Hardware watchpoints work properly with these settings.
Mind, though, that Dynamic Intimate Shared Memory (DISM) will be used instead
of ISM in this case. That's not recommended for Oracle databases and therefore
shouldn't be done outside the lab.
Nenad
https://nenadnoveljic.com/blog/
From: oracle-l-bounce@xxxxxxxxxxxxx <oracle-l-bounce@xxxxxxxxxxxxx> On Behalf
Of Noveljic Nenad
Sent: Dienstag, 8. Januar 2019 13:49
To: ORACLE-L (oracle-l@xxxxxxxxxxxxx) <oracle-l@xxxxxxxxxxxxx>
Subject: gdb doesn't stop at a hardware watchpoint on a memory location
As you may see in the subject, my question isn't directly related to the Oracle
database. However, some contributors to the list regularly use gdb for
troubleshooting Oracle.
So, I hope it's not completely inappropriate to post this gdb related question
here.
The problem I have is that the execution isn't stopped when the watched memory
location gets changed.
You can find the detailed description below.
First, I'll inspect the content of the memory location 0x117510e20:
p/x *0x117510e20
$398 = 0x1000000
Then I'll set the hardware watchpoint on this address:
(gdb) wa *0x117510e20
Hardware watchpoint 171: *0x117510e20
As you can see, the watchpoint 171 is enabled:
(gdb) info watch
Num Type Disp Enb Address What
171 hw watchpoint keep y *0x117510e20
Finally, I'll continue execution until the next breakpoint is reached:
continue
Breakpoint 166, ... in ...
Unexpectedly, the data in the memory location changed without triggering the
watchpoint:
(gdb) p/x *0x117510e20
$399 = 0x5000000
Can anybody explain why the watchpoint is not being triggered in this case?
I'm using the following gdb version on Solaris 11.3:
$ gdb --version
GNU gdb (GDB) 7.6
Copyright (C) 2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "i386-pc-solaris2.11".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Best regards,
Nenad
https://nenadnoveljic.com/
____________________________________________________
Please consider the environment before printing this e-mail.
Bitte denken Sie an die Umwelt, bevor Sie dieses E-Mail drucken.
Important Notice
This message is intended only for the individual named. It may contain
confidential or privileged information. If you are not the named addressee you
should in particular not disseminate, distribute, modify or copy this e-mail.
Please notify the sender immediately by e-mail, if you have received this
message by mistake and delete it from your system.
Without prejudice to any contractual agreements between you and us which shall
prevail in any case, we take it as your authorization to correspond with you by
e-mail if you send us messages by e-mail. However, we reserve the right not to
execute orders and instructions transmitted by e-mail at any time and without
further explanation.
E-mail transmission may not be secure or error-free as information could be
intercepted, corrupted, lost, destroyed, arrive late or incomplete. Also
processing of incoming e-mails cannot be guaranteed. All liability of Vontobel
Holding Ltd. and any of its affiliates (hereinafter collectively referred to as
"Vontobel Group") for any damages resulting from e-mail use is excluded. You
are advised that urgent and time sensitive messages should not be sent by
e-mail and if verification is required please request a printed version.
Please note that all e-mail communications to and from the Vontobel Group are
subject to electronic storage and review by Vontobel Group. Unless stated to
the contrary and without prejudice to any contractual agreements between you
and Vontobel Group which shall prevail in any case, e-mail-communication is for
informational purposes only and is not intended as an offer or solicitation for
the purchase or sale of any financial instrument or as an official confirmation
of any transaction.
The legal basis for the processing of your personal data is the legitimate
interest to develop a commercial relationship with you, as well as your consent
to forward you commercial communications. You can exercise, at any time and
under the terms established under current regulation, your rights. If you
prefer not to receive any further communications, please contact your client
relationship manager if you are a client of Vontobel Group or notify the
sender. Please note for an exact reference to the affected group entity the
corporate e-mail signature. For further information about data privacy at
Vontobel Group please consult www.vontobel.com<https://www.vontobel.com>.
<html xmlns="http://www.w3.org/1999/xhtml";>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css">p { font-family: Arial;font-size:9pt }</style>
</head>
<body>
<p>
<br>Important Notice</br>
<br />
This message is intended only for the individual named. It may contain
confidential or privileged information. If you are not the named addressee you
should in particular not disseminate, distribute, modify or copy this e-mail.
Please notify the sender immediately by e-mail, if you have received this
message by mistake and delete it from your system.<br />
Without prejudice to any contractual agreements between you and us which shall
prevail in any case, we take it as your authorization to correspond with you by
e-mail if you send us messages by e-mail. However, we reserve the right not to
execute orders and instructions transmitted by e-mail at any time and without
further explanation.<br />
E-mail transmission may not be secure or error-free as information could be
intercepted, corrupted, lost, destroyed, arrive late or incomplete. Also
processing of incoming e-mails cannot be guaranteed. All liability of Vontobel
Holding Ltd. and any of its affiliates (hereinafter collectively referred to as
"Vontobel Group") for any damages resulting from e-mail use is excluded. You
are advised that urgent and time sensitive messages should not be sent by
e-mail and if verification is required please request a printed version.</br>
Please note that all e-mail communications to and from the Vontobel Group are
subject to electronic storage and review by Vontobel Group. Unless stated to
the contrary and without prejudice to any contractual agreements between you
and Vontobel Group which shall prevail in any case, e-mail-communication is for
informational purposes only and is not intended as an offer or solicitation for
the purchase or sale of any financial instrument or as an official confirmation
of any transaction.<br />
The legal basis for the processing of your personal data is the legitimate
interest to develop a commercial relationship with you, as well as your consent
to forward you commercial communications. You can exercise, at any time and
under the terms established under current regulation, your rights. If you
prefer not to receive any further communications, please contact your client
relationship manager if you are a client of Vontobel Group or notify the sender.
Please note for an exact reference to the affected group entity the corporate
e-mail signature.
For further information about data privacy at Vontobel Group please consult <a
href="https://www.vontobel.com";>www.vontobel.com</a>.<br />
</p>
</body>
</html>
