Branch instruction with no operand causes gas to segfault on armel

[Dave Martin]

Binary package hint: binutils

Affects: 2.19.51.20090622-0ubuntu1 (karmic)
Does not affect: 2.19.1-0ubuntu3 (jaunty)

An input file consisting of a single "b" character (with or without newline) is sufficient to reproduce the error. However, "beq" also works.

I haven't been able to determine whether the parsing of any other instructions is affected; "mov" with no operands causes gas to generate an error message normally, for example.

[Dave Martin (dave-martin-arm)]

This bug may affect upstream, but I've not been able to check yet.

[Matthias Klose (doko)]

may be caused by:

2009-05-05 Ramana Radhakrishnan <email address hidden>

        * config/tc-arm.h: Fix typo in comment.
        (ARM_IS_FUNC): New macro.
        (MD_APPLY_SYM_VALUE): Define.

        * config/tc-arm.c (do_blx): Retain BFD_RELOC_ARM_PCREL_BLX for
        all versions of EABI.
        (relax_branch): Do not relax for branches to ARM functions.
        (md_pcrel_from_section): Set up base correctly for
        BFD_RELOC_THUMB_PCREL_BLX, BFD_RELOC_THUMB_PCREL_CALL,
        BFD_RELOC_THUMB_PCREL_BRANCH23, BFD_RELOC_ARM_PCREL_BLX
        BFD_RELOC_ARM_PCREL_CALL.
        (md_apply_fix): Flip bl to blx where possible.
        Flip blx to bl where possible.
        (arm_force_relocation): Force relocations for
        BFD_RELOC_ARM_PCREL_JUMP, BFD_RELOC_ARM_PCREL_JUMP,
        BFD_RELOC_ARM_PCREL_BLX, BFD_RELOC_THUMB_PCREL_BLX,
        BFD_RELOC_THUMB_PCREL_BRANCH20, BFD_RELOC_THUMB_PCREL_BRANCH23,
        BFD_RELOC_THUMB_PCREL_BRANCH25.
        (arm_apply_sym_value): New function.

[Matthias Klose (doko)]

Program received signal SIGSEGV, Segmentation fault.
symbol_get_tc (s=0x0) at ../../gas/symbols.c:2699
2699 if (LOCAL_SYMBOL_CHECK (s))
(gdb) bt
#0 symbol_get_tc (s=0x0) at ../../gas/symbols.c:2699
#1 0x0003d624 in arm_force_relocation (fixp=0x8f410) at ../../gas/config/tc-arm.c:20811
#2 0x0003da1c in md_pcrel_from_section (fixP=0x8f410, seg=0xa26a0) at ../../gas/config/tc-arm.c:18871
#3 0x0002c498 in fix_segment (abfd=<value optimized out>, sec=0xa26a0, xxx=<value optimized out>)
    at ../../gas/write.c:1011
#4 0x40067108 in bfd_map_over_sections (abfd=0x8d130, operation=0x2c26c <fix_segment>,
    user_storage=0x0) at ../../bfd/section.c:1232
#5 0x0002b90c in write_object_file () at ../../gas/write.c:1735
#6 0x0000cec8 in main (argc=578264, argv=0xbe9c3814) at ../../gas/as.c:1232

[Matthias Klose (doko)]

[forwarded from https://launchpad.net/bugs/396049]

Seen with 2.19.51.20090713, not 2.19.1-0ubuntu3:

An input file consisting of a single "b" character (with or without newline) is
sufficient to reproduce the error. However, "beq" also works.

I haven't been able to determine whether the parsing of any other instructions
is affected; "mov" with no operands causes gas to generate an error message
normally, for example.

Program received signal SIGSEGV, Segmentation fault.
symbol_get_tc (s=0x0) at ../../gas/symbols.c:2699
2699 if (LOCAL_SYMBOL_CHECK (s))
(gdb) bt
#0 symbol_get_tc (s=0x0) at ../../gas/symbols.c:2699
#1 0x0003d624 in arm_force_relocation (fixp=0x8f410) at
../../gas/config/tc-arm.c:20811
#2 0x0003da1c in md_pcrel_from_section (fixP=0x8f410, seg=0xa26a0) at
../../gas/config/tc-arm.c:18871
#3 0x0002c498 in fix_segment (abfd=<value optimized out>, sec=0xa26a0,
xxx=<value optimized out>)
    at ../../gas/write.c:1011
#4 0x40067108 in bfd_map_over_sections (abfd=0x8d130, operation=0x2c26c
<fix_segment>,
    user_storage=0x0) at ../../bfd/section.c:1232
#5 0x0002b90c in write_object_file () at ../../gas/write.c:1735
#6 0x0000cec8 in main (argc=578264, argv=0xbe9c3814) at ../../gas/as.c:1232

Related to?

2009-05-05 Ramana Radhakrishnan <email address hidden>

        * config/tc-arm.h: Fix typo in comment.
        (ARM_IS_FUNC): New macro.
        (MD_APPLY_SYM_VALUE): Define.

        * config/tc-arm.c (do_blx): Retain BFD_RELOC_ARM_PCREL_BLX for
        all versions of EABI.
        (relax_branch): Do not relax for branches to ARM functions.
        (md_pcrel_from_section): Set up base correctly for
        BFD_RELOC_THUMB_PCREL_BLX, BFD_RELOC_THUMB_PCREL_CALL,
        BFD_RELOC_THUMB_PCREL_BRANCH23, BFD_RELOC_ARM_PCREL_BLX
        BFD_RELOC_ARM_PCREL_CALL.
        (md_apply_fix): Flip bl to blx where possible.
        Flip blx to bl where possible.
        (arm_force_relocation): Force relocations for
        BFD_RELOC_ARM_PCREL_JUMP, BFD_RELOC_ARM_PCREL_JUMP,
        BFD_RELOC_ARM_PCREL_BLX, BFD_RELOC_THUMB_PCREL_BLX,
        BFD_RELOC_THUMB_PCREL_BRANCH20, BFD_RELOC_THUMB_PCREL_BRANCH23,
        BFD_RELOC_THUMB_PCREL_BRANCH25.
        (arm_apply_sym_value): New function.

[Matthias Klose (doko)]

works with 2.19.51.20090423, fails with 2.19.51.20090508

[Nickc (nickc)]

Created attachment 4053
Handle NULL pointers in xxx_IS_FUNC macros

[Nickc (nickc)]

Hi Matthias,

  Thanks for reporting this bug. I will be applying the uploaded patches to the
sources in order to fix it.

Cheers
  Nick

gas/ChangeLog
2009-07-14 Nick Clifton <email address hidden>

 PR 10387
 * config/tc-arm.h (THUMB_IS_FUNC): Handle a NULL pointer.
 (ARM_IS_FUNC): Likewise.

[Cvs-commit (cvs-commit)]

Subject: Bug 10387

CVSROOT: /cvs/src
Module name: src
Changes by: <email address hidden> 2009-07-14 15:38:21

Modified files:
 gas : ChangeLog
 gas/config : tc-arm.h

Log message:
 PR 10387
 * config/tc-arm.h (THUMB_IS_FUNC): Handle a NULL pointer.
 (ARM_IS_FUNC): Likewise.

Patches:
http://sources.redhat.com/cgi-bin/cvsweb.cgi/src/gas/ChangeLog.diff?cvsroot=src&r1=1.3847&r2=1.3848
http://sources.redhat.com/cgi-bin/cvsweb.cgi/src/gas/config/tc-arm.h.diff?cvsroot=src&r1=1.51&r2=1.52

[Launchpad Janitor (janitor)]

This bug was fixed in the package binutils - 2.19.51.20090714-0ubuntu1

---------------
binutils (2.19.51.20090714-0ubuntu1) karmic; urgency=low

  * Snapshot, taken from the trunk 20090714.
    - Fix PR gas/10387 (branch instruction with no operand causes gas
      to segfault on armel). LP: #396049.
    - 128_arm_eabi_align64.dpatch: Remove, integrated upstream.
  * debian/*.shlibs: Update to the version from the trunk.

 -- Matthias Klose <email address hidden> Tue, 14 Jul 2009 12:48:09 -0400