Red Hat Bugzilla – Bug 185337
p errno does not work when stopped at a breakpoint
Last modified: 2015-01-07 19:12:29 EST
Description of problem:
I compiled a simple test program, started gdb on it, set a breakpoint, started
my program, and after it hit the breakpoint, attempted to "p errno". Instead
of printing the value of errno, gdb said "Cannot access memory at address 0x8"
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1.Compile the attached program with gcc -o convert -g convert.c
4.run utf8 cp850 foobarbaz
Cannot access memory at address 0x8
$1 = 0
This works on RHEL3, hence regression.
Created attachment 126068 [details]
source for simple test program
This is also broken in rawhide with gdb-220.127.116.11-1.122
Please retest if compiled with -ggdb3: gcc -o convert -ggdb3 convert.c
FC5 gdb OK Cannot find thread-local variables
CVS gdb OK Cannot access memory at address 0x8
FC4 gdb OK Cannot access memory at address 0x8
As it is fixed by on of the Red Hat vendor patches, suggesting to extend the
error message by: ", try gcc -ggdb3"
Created attachment 134901 [details]
Access TLS symbols without DWARF debuginfo
Attached patch implements accessing TLS symbols without the debuginfo
suggestions as not always such associatet debuginfo is available. It checks
SYMBOL_BFD_SECTION (msymbol)->flags & SEC_THREAD_LOCAL
symbols, implements for them new `UNOP_MEMVAL_TLS' and reuses for them former
Created attachment 134902 [details]
Ignore TLS symbols for non-TLS programs
IMO the right way is to ignore TLS symbols for inferiors without activated
Created attachment 134903 [details]
Suggest how to resolve the missing "errno" symbol
Also attached suggestion patch how to deal with the most common "errno" symbol
for the most common under-ggdb3 compiled programs.
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release. Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products. This request is not yet committed for inclusion in an Update
This bugzilla has Keywords: Regression.
Since no regressions are allowed between releases,
it is also being marked as a blocker for this release.
Please resolve ASAP.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.