Red Hat Bugzilla – Bug 87897
RFE: "info registers" gives segment base and limit for %gs
Last modified: 2010-05-07 16:10:31 EDT
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Description of problem:
Please enhance "info registers" to list the current base and limit values for
segment registers on ix86. This would be particularly useful when debugging
code which uses NPTL locale/threads/etc on i686 because /lib/tls/libc.so.6 uses
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Run any program under gdb; stop at a breakpoint.
2. (gdb) info registers
Actual Results: cs 0x23 35
ss 0x2b 43
ds 0x2b 43
es 0x2b 43
fs 0x0 0
gs 0x0 0
Expected Results: cs 0x23 35 0 0xfffff
ss 0x2b 43 0xc0000000 0xfdfff
ds 0x2b 43 0 0xfffff
es 0x2b 43 0 0xfffff
fs 0x0 0
gs 0x33 51 0x42130020 0xfffff
Probably, full generality will require a new kernel call to report the values,
although in the specific case of %gs usage by NPTL, there may be a backdoor for
NPTL to cooperate with gdb.
Red Hat apologizes that these issues have not been resolved yet. We do want to
make sure that no important bugs slip through the cracks.
Red Hat Linux 7.3 and Red Hat Linux 9 are no longer supported by Red Hat, Inc.
They are maintained by the Fedora Legacy project (http://www.fedoralegacy.org/)
for security updates only. If this is a security issue, please reassign to the
'Fedora Legacy' product in bugzilla. Please note that Legacy security update
support for these products will stop on December 31st, 2006.
If this is not a security issue, please check if this issue is still present
in a current Fedora Core release. If so, please change the product and version
to match, and check the box indicating that the requested information has been
If you are currently still running Red Hat Linux 7.3 or 9, please note that
Fedora Legacy security update support for these products will stop on December
31st, 2006. You are strongly advised to upgrade to a current Fedora Core release
or Red Hat Enterprise Linux or comparable. Some information on which option may
be right for you is available at http://www.redhat.com/rhel/migrate/redhatlinux/.
Any bug still open against Red Hat Linux 7.3 or 9 at the end of 2006 will be
closed 'CANTFIX'. Again, if this bug still exists in a current release, or is a
security issue, please change the product as necessary. We thank you for your
help, and apologize again that we haven't handled these issues to this point.
This request still applies to Fedora Core 6 test 1, gdb-6.5-3.fc6rh.
There is no box to check that I am supplying the requested info; so, change to
NeedInfo - Assignee. (Entered page via http://bugzilla.redhat.com/bugzilla, was
recognized by cookie as logged in, typed bug number in GoTo Bug# box, typed
<Enter>. Searched page for "req" using Find command in Firefox (<ctrl>F) to be
sure that I did not overlook any checkbox about requested information.)
Now there is a "I am providing the requested information" box, just under the
"Please create attachement". So I will check it.
Fedora Core 5 and Fedora Core 6 are, as we're sure you've noticed, no longer
test releases. We're cleaning up the bug database and making sure important bug
reports filed against these test releases don't get lost. It would be helpful if
you could test this issue with a released version of Fedora or with the latest
development / test release. Thanks for your help and for your patience.
[This is a bulk message for all open FC5/FC6 test release bugs. I'm adding
myself to the CC list for each bug, so I'll see any comments you make after this
and do my best to make sure every issue gets proper attention.]
This enhancement request still applies. "info registers" should list the base
and limit for %gs, but does not. I change the bugreport Version to "devel".
(gdb) info reg
. . .
cs 0x73 115
ss 0x7b 123
ds 0x7b 123
es 0x7b 123
fs 0x0 0
gs 0x33 51
(gdb) show version
GNU gdb Red Hat Linux (6.6-7.fc7rh)
Thanks. This may be better (read: more quickly, or ever) addressed by upstream
gdb -- http://sourceware.org/cgi-bin/gnatsweb.pl .