Description of problem: Upstream GDB needs one of these commands to access `errno' in nonthreaded apps: (gdb) print *('*__GI___errno_location')() or (gdb) print *((int *(*)())__errno_location)() Version-Release number of selected component (if applicable): gcc-4.1.2-33.x86_64 glibc-debuginfo-2.7-2.x86_64 How reproducible: Always. Steps to Reproduce: 1. echo 'int main () {}' >main.c 2. gcc -g -o main main.c 3. upstream/gdb ./main 4. start 5. print *__errno_location() Actual results: Cannot access memory at address 0xffffffffaaac3698 Expected results: $1 = 0 Additional info: The error is due to `__errno_location' having no debug info and defaulting to: (gdb) ptype __errno_location type = int () as GDB prefers DW_AT_MIPS_linkage_name over DW_AT_name, if present. But glibc-debuginfo-2.7-2.x86_64 has: <1><81a0>: Abbrev Number: 12 (DW_TAG_subprogram) <81a2> DW_AT_name : (indirect string, offset: 0x280e): __errno_location <81a8> DW_AT_MIPS_linkage_name: (indirect string, offset: 0x2808): *__GI___errno_location so one needs to use one of the workarounding commands in the Description. There is now workaround in gdb-6.7.1-3.fc9 to prefer DW_AT_name over DW_AT_MIPS_linkage_name for plain C Compilation Units. AFAIK DW_AT_MIPS_linkage_name is so far in use only as an insufficient debuginfo reading GDB implementation helper for C++ methods. It may not make sense to fix DW_AT_MIPS_linkage_name as it should rather be dropped and GDB implementation improved to cope with C++ without it.
That's not a GCC bug. In glibc we have extern int *__errno_location (void) __asm ("__GI___errno_location"); and then add an alias in asm, so that calls to __errno_location from libc.so are binding to the libc.so definition always and don't go through PLT, while __errno_location is exported. Current ld has -Bsymbolic-functions and -Bsymbolic-data support, so perhaps we could use it instead eventually if we fix bugs in it.
Based on the date this bug was created, it appears to have been reported during the development of Fedora 8. In order to refocus our efforts as a project we are changing the version of this bug to '8'. If this bug still exists in rawhide, please change the version back to rawhide. (If you're unable to change the bug's version, add a comment to the bug and someone will change it for you.) Thanks for your help and we apologize for the interruption. The process we're following is outlined here: http://fedoraproject.org/wiki/BugZappers/F9CleanUp We will be following the process here: http://fedoraproject.org/wiki/BugZappers/HouseKeeping to ensure this doesn't happen again.
We cannot use -Bsymbolic in any form. The malloc functions must be interceptible. With gdb working differently now, I assume there is nothing left to do. If there is, reopen.