[kaffe] weird GC error with bad class format
Timothy Stack
stack at cs.utah.edu
Mon Feb 3 13:29:02 PST 2003
> Hi everyone.
hi,
> i'm currently modifying kaffe's verifier (not posted yet because i'm
> trying to get it more or less bug-for-bug compatible with Sun...they don't
> really follow their own damn spec too closely, it turns out) and class
> loader to take advantage of a GJ-like signature for running generic code
> faster.
Could you post it anyways? Itd be nice to take a look at it.
> the problem comes when the GJ Signature attribute is malformed. the
> method readAttribute() in readClass.c returns false, and
>
> kaffe-bin: mem/gc-incremental.c:1064: gcFree: Assertion `!!!"Attempt to
> explicitly free nonfixed object"' failed.
>
> is what i get.
So, I'm not seeing this, could you use gdb and give us a back trace? I am
seeing another error though, libraries/clib/native/SystemClassLoader.c has
a broken conditional:
if (!strcmp(info.classname, "java.lang.NoClassDefFoundError")) {
...
}
else if ((info.type & KERR_EXCEPTION)
&& !strcmp(info.classname, "java.lang.NoClassDefFoundError"))
{
}
It looks like patch just messed up, the second 'if' is the correct
conditional, but its block is empty. So, the block should be deleted and
the conditional moved up:
if ((info.type & KERR_EXCEPTION)
&& !strcmp(info.classname, "java.lang.NoClassDefFoundError"))
{
...
}
> this is bad because that means whenever a class file is
> corrupted a little bit (or at least the attributes in a class file are
> corrupted) and readAttribute returns false, this pretty bad thing happens.
>
> to reproduce this, simply add the following case to readAttribute:
>
> else if (!strcmp(name->data, "Signature")) {
> return false;
> }
Are you using the current CVS?
> cheers,
> ~rob
tim stack
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