>Number: 158719 >Category: gnu >Synopsis: [patch] Fix kgdb on sparc64 >Confidential: no >Severity: non-critical >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Fri Jul 08 07:40:01 UTC 2011 >Closed-Date: >Last-Modified: >Originator: Peter Jeremy >Release: FreeBSD 8.2-STABLE amd64 >Organization: n/a >Environment: System: FreeBSD sb1500.vk2pj.dyndns.org 9.0-CURRENT FreeBSD 9.0-CURRENT #1: Wed\ Jun 22 17:53:58 EST 2011 [email protected]:/usr/obj/usr/src/sys/sb1\ 500 sparc64
Patch also tested on: FreeBSD server.vk2pj.dyndns.org 8.2-STABLE FreeBSD 8.2-STABLE #11: Fri Apr 22 11:55:58 EST 2011 [email protected]:/var/obj/usr/src/sys/server amd64 >Description: kgdb does not work on sparc64. Following some investigation, the problem is that the sparc64 kgdb has two "core_stratum" target_ops structures active - the default "Local core dump file" defined in contrib/gdb/gdb/corelow.c and the FreeBSD-specific "kernel core dump file" defined in gnu/usr.bin/gdb/kgdb/trgt.c On at least i386 and amd64, the "Local core dump file" is inhibited by statically defining coreops_suppress_target as non-zero in gnu/usr.bin/gdb/libgdb/fbsd-threads.c (this file defines "FreeBSD multithreaded core dump file" target_ops which is itself inhibited by fbsdcoreops_suppress_target in gnu/usr.bin/gdb/kgdb/trgt.c). sparc64 does not include fbsd-threads.c and therefore the "Local core dump file" is not inhibited. As a result, contrib/gdb/gdb/target.c::find_core_target() finds multiple targets and returns NULL. Note that it's possible that similar problems exist on other architectures. >How-To-Repeat: Run "kgdb /boot/kernel/kernel /dev/mem" as root on sparc64. It will report "GDB can't read core files on this machine." >Fix: It's not possible to directly inhibit the "Local core dump file" by defining coreops_suppress_target in trgt.c because that results in a duplicate definition on (eg) amd64. Likewise a weak DATA symbol does not override a strong BSS symbol. The following patch therefore defines coreops_suppress_target in a file that is only active on sparc64 kgdb. Index: gnu/usr.bin/gdb/kgdb/trgt_sparc64.c =================================================================== RCS file: /usr/ncvs/src/gnu/usr.bin/gdb/kgdb/trgt_sparc64.c,v retrieving revision 1.8 diff -u -r1.8 trgt_sparc64.c --- gnu/usr.bin/gdb/kgdb/trgt_sparc64.c 1 May 2008 20:36:48 -0000 1.8 +++ gnu/usr.bin/gdb/kgdb/trgt_sparc64.c 8 Jul 2011 06:17:55 -0000 @@ -197,3 +197,9 @@ /* printf("%s: %lx =%s\n", __func__, pc, pname); */ return (NULL); } +/* +** Disable the default "Local core dump file" target. This is done in +** libgdb/fbsd-threads.c for most targets but that file is not used on +** sparc64 +*/ +int coreops_suppress_target = 1; >Release-Note: >Audit-Trail: >Unformatted: _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-bugs To unsubscribe, send any mail to "[email protected]"
