Bug 165025

Summary:	GDB intermittently fails with gcj-generated (BC-ABI) .sos.
Product:	Red Hat Enterprise Linux 4	Reporter:	Andrew Overholt <overholt>
Component:	gdb	Assignee:	Jan Kratochvil <jan.kratochvil>
Status:	CLOSED ERRATA	QA Contact:	Jay Turner <jturner>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	4.0	CC:	cagney, jan.kratochvil, srevivo
Target Milestone:	---
Target Release:	---
Hardware:	powerpc
OS:	Linux
Whiteboard:
Fixed In Version:	RHBA-2007-0811	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2007-11-15 16:11:30 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	165039, 221048

Description Andrew Overholt 2005-08-03 17:47:52 UTC

Description of problem:
GDB intermittently fails with gcj-generated (BC-ABI) .sos.

Version-Release number of selected component (if applicable):
gdb-6.3.0.0-1.24.ppc

How reproducible:
Always ... although no small test case unfortunately.

Steps to Reproduce:
1. start eclipse
2. gdb /usr/bin/java <pid>
3. thread apply all bt (or almost any command ... it happens quite frequently)
  
Actual results:
../../gdb-6.3/gdb/dwarf2-frame.c:454: internal-error: Unknown CFI 47 encountered.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) y
../../gdb-6.3/gdb/dwarf2-frame.c:454: internal-error: Unknown CFI 47 encountered.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Create a core file of GDB? (y or n) n

Expected results:
No gdb failures.

Additional info:
Andrew Cagney has looked into this and knows what the problem is.

Comment 1 Andrew Cagney 2005-08-03 19:32:37 UTC

GDB needs to handle DW_CFA_GNU_negative_offset_extended which has been in the
java sources since ~2001:

1.2          (aph      03-Jun-01):       .byte     0x2f     /* 
DW_CFA_GNU_negative_offset_extended */

It's actually 100% reproducable, and it occures on rhel4.

Comment 2 Andrew Cagney 2005-08-03 19:34:50 UTC

This needs to be added to dwarf2-frame.c:

            case DW_CFA_GNU_negative_offset_extended:
              insn_ptr = read_uleb128 (insn_ptr, insn_end, &reg);
              insn_ptr = read_uleb128 (insn_ptr, insn_end, &offset);
              offset *= fs->data_align;
              dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
              fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
              fs->regs.reg[reg].loc.offset = -offset;
              break;

Comment 3 Jan Kratochvil 2006-12-31 06:08:01 UTC

Patch committed as is to RawHide incl. an i386 testcase:
* Sat Dec 30 2006 Jan Kratochvil <jan.kratochvil> - 6.5-22
- Fix unwinding crash on older gcj(1) code (extended CFI support) (BZ 165025).

Comment 4 RHEL Program Management 2007-05-09 11:15:57 UTC

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
release.

Comment 7 Andrew Cagney 2007-07-17 18:24:32 UTC

Test case included.  Fixes crash.

Comment 13 errata-xmlrpc 2007-11-15 16:11:30 UTC

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.

http://rhn.redhat.com/errata/RHBA-2007-0811.html