[Bug go/60134] New: runtime_unmarkspan panics with "unaligned pointer"

[Bug go/60134] New: runtime_unmarkspan panics with "unaligned pointer"

[vogt at linux dot vnet.ibm.com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60134

            Bug ID: 60134
           Summary: runtime_unmarkspan panics with "unaligned pointer"
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: go
          Assignee: ian at airs dot com
          Reporter: vogt at linux dot vnet.ibm.com

(using git commit id e63988cca99cbbf6e5c459379309fe3359fe7c09)

The test case convert.go fails with a panic in a panic on System/z:

-- snip --
fatal error: markspan: unaligned pointer

goroutine 1 [running]:
runtime_dopanic
    ../../../libgo/runtime/panic.c:77
runtime_throw
    ../../../libgo/runtime/panic.c:115
runtime_unmarkspan
    ../../../libgo/runtime/mgc0.c:2452
__go_free
    ../../../libgo/runtime/malloc.goc:240
__go_panic
    ../../../libgo/runtime/go-panic.c:106
runtime_panicstring
    ../../../libgo/runtime/panic.c:134
__go_map_index
    ../../../libgo/runtime/go-map-index.c:92
reflect.canonicalize
    ../../../libgo/go/reflect/type.go:1782
reflect.toType
    ../../../libgo/go/reflect/type.go:1791
reflect.TypeOf
    ../../../libgo/go/reflect/type.go:1026
fmt..import
    ../../../libgo/go/fmt/print.go:643
__go_init_main
    /home/vogt/src/git/gcc/gcc/testsuite/go.test/test/convert.go:9
runtime_main
    ../../../libgo/runtime/proc.c:555
kickoff
    ../../../libgo/runtime/proc.c:232
-- snip --

It turns out that mgc0.c:runtime_unmarkspan() is called with a pointer that
should be 16 byte aligned (wordsPerBitmapWord) but is actually only 8 byte
aligned.  The original pointer points to the stack variable "Defer d" in
proc.c:runtime_main().  I guess the code should somehow enforce that "Defer d"
is aligned to mgc0.c:wordsPerBitmapWord bytes, although I'm not sure about the
right way to fix this.

Note: Even though adding "__attribute__ ((align(16)))" for d fixes the problem
for me, the test case still fails, but that is another issue that may or may
not be platform specific.  In any case I'll look into that and open another bug
report if necessary.

[Bug go/60134] runtime_unmarkspan panics with "unaligned pointer"

[ian at airs dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60134

--- Comment #1 from Ian Lance Taylor <ian at airs dot com> ---
I don't know which repository your git commit ID refers to.  The gofrontend
uses Mercurial and GCC uses Subversion.

I suspect this problem was fixed by revision 205940 in the GCC Subversion
repository, committed 2013-12-12,
http://gcc.gnu.org/ml/gcc-patches/2013-12/msg01202.html .

Do the sources you are building include that patch?

[Bug go/60134] runtime_unmarkspan panics with "unaligned pointer"

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60134

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Ian Lance Taylor from comment #1)
> I don't know which repository your git commit ID refers to.  The gofrontend
> uses Mercurial and GCC uses Subversion.

The git commit ID referenced is the official git which uses git-svn:
http://gcc.gnu.org/git/?p=gcc.git;a=commit;h=e63988cca99cbbf6e5c459379309fe3359fe7c09

> 
> I suspect this problem was fixed by revision 205940 in the GCC Subversion
> repository, committed 2013-12-12,
> http://gcc.gnu.org/ml/gcc-patches/2013-12/msg01202.html .
> 
> Do the sources you are building include that patch?



which corresponds to revision 205617 which is before the revision you said it
was fixed in.

Thanks,
Andrew Pinski

[Bug go/60134] runtime_unmarkspan panics with "unaligned pointer"

[ian at airs dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60134

Ian Lance Taylor <ian at airs dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED

--- Comment #3 from Ian Lance Taylor <ian at airs dot com> ---
Thanks Andrew.  Assuming this is fixed.  Please reopen if not.

[Bug go/60134] runtime_unmarkspan panics with "unaligned pointer"

[vogt at linux dot vnet.ibm.com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60134

--- Comment #4 from Dominik Vogt <vogt at linux dot vnet.ibm.com> ---
On Wed, Feb 12, 2014 at 12:34:06AM +0000, ian at airs dot com wrote:
> I suspect this problem was fixed by revision 205940 in the GCC Subversion
> repository, committed 2013-12-12,
> http://gcc.gnu.org/ml/gcc-patches/2013-12/msg01202.html .

Yes, that fixes it.  Thanks.

Ciao

Dominik ^_^  ^_^

[Bug go/60134] runtime_unmarkspan panics with "unaligned pointer"

[vogt at linux dot vnet.ibm.com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60134

Dominik Vogt <vogt at linux dot vnet.ibm.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |CLOSED

--- Comment #5 from Dominik Vogt <vogt at linux dot vnet.ibm.com> ---
Fix verified by reporter.