Re: Rogue Pointer

[Michael Livshin]

"Dale P. Smith" <address@hidden> writes:

> I'm get a "Error in scm_gc_mark during GC: rogue pointer in heap" when
> the first gc happens in cvs guile.  This is in an Apache module.
> 
> What is a "rogue pointer"?  I image it's a pointer into gc controlled
> memory from somewhere in the heap. Or is it the other way around, a
> pointer to memory that's not gc controlled?

the latter (i.e. a pointer that is supposed to point at a Guile cell
but doesn't).

most likely, this means a corrupted cell.

> I haven't touched my Apache guile module since about December of last
> year, so I rebuilt it with Guile configured --disable-deprecated and
> fixed all the errors to deprecated functions/macros to make sure it will
> build with the upcoming release.  I'm not sure if I intruduced a bug,
> Guile gc has changed, or Apache has changed (there may have been some
> security updates).

try configuring Guile with --enable-debug-freelist, and do
(gc-set-debug-check-freelist! #t) somewhere close to the crash
(actually, the earlier the better, but it impacts performance a lot).
see what happens.

if that doesn't help, compile Guile with -DSCM_DEBUG_CELL_ACCESSES=1
and do (set-debug-cell-accesses! #t).  see what happens.

-- 
You know better than to trust a strange computer.