In message <[EMAIL PROTECTED]>
[EMAIL PROTECTED] (Jon Burgess) wrote:
> When the attached code is run under valgrind I get the following error.
>
> ==13906== Invalid read of size 8
> ==13906== at 0x6B4E13C: ruby_xml_attr_free (ruby_xml_attr.c:12)
> ==13906== by 0x3C2524A9CD: rb_gc_call_finalizer_at_exit (gc.c:1928)
> ==13906== by 0x3C2522FA92: ruby_finalize_1 (eval.c:1548)
> ==13906== by 0x3C25238BFF: ruby_cleanup (eval.c:1582)
> ==13906== by 0x3C25238D28: ruby_stop (eval.c:1619)
> ==13906== by 0x3C252444C3: ruby_run (eval.c:1640)
> ==13906== by 0x4007E2: main (main.c:48)
> ==13906== Address 0x6AE4790 is 40 bytes inside a block of size 96 free'd
> ==13906== at 0x4A055AB: free (vg_replace_malloc.c:233)
> ==13906== by 0x3C2524A737: ruby_xfree (gc.c:159)
> ==13906== by 0x3C304507AE: xmlRemoveProp (in /usr/lib64/libxml2.so.2.6.28)
> ==13906== by 0x6B49C3D: ruby_xml_node_property_set (ruby_xml_node.c:1892)
> ==13906== by 0x3C25235BAD: rb_call0 (eval.c:5815)
> ==13906== by 0x3C252360B7: rb_call (eval.c:6062)
> ==13906== by 0x3C2523DAB3: rb_eval (eval.c:3429)
> ==13906== by 0x3C2524442A: ruby_exec_internal (eval.c:1608)
> ==13906== by 0x3C25244474: ruby_exec (eval.c:1628)
> ==13906== by 0x3C2524449F: ruby_run (eval.c:1638)
> ==13906== by 0x4007E2: main (main.c:48)
> ==13906==
>
> I think the issue is with ruby_xml_node_property_set() calling
> xmlRemoveProp() which both removes the attribute from the node and frees
> it. I think freeing the attribute needs to be conditional on there being
> no other references.
That is one problem, yes.
It is worse than that though, because if the node which the
attribute is attached to is freed then the attribute will be
freed (even if there are other references to it) and there is
no easy way to find out which attributes need to be kept.
I guess you would have to walk the entire node tree checking
the _private reference count of each attribute and unlinking
anything that is shared before freeing the node?
It's horrible anyway...
Tom
--
Tom Hughes ([EMAIL PROTECTED])
http://www.compton.nu/
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