strange effect with --enable-fast-malloc=full

[Falk Brettschneider]

Hi!

Lubos Lunak wrote:

>On út 16. duben 2002 14:07, Falk Brettschneider wrote:
>
>>Hi!
>>
>>I tried to compile KDE_3_0_BRANCH with using the
>>--enable-fast-malloc=full flag in configure, first for kdecore only,
>>second for the whole kdesupport, kdelibs, kdebase.
>>But now always I got a strange effect when closing my KDE application.
>>Somehow it hangs forever in an infinite loop somewhere in malloc.
>>Whenever I interrupt it in gdb, it shows the same callstack:
>>  http://www.geocities.com/gigafalk/strange.jpg
>>
>
> Hmm. The backtrace is completely useless - the only 3 things I can see is 
>that 1) the backtrace ends in malloc(), 2) you don't have libkdecore with 
>debug info
>
sorry, now I recompiled kdecore with debug info and I saw it loops back 
in line 2963 of malloc.c because there's always a p != 0.

> even though you have it in libqt and 3) you use Keramik. Could you 
>give me a testcase, 
>
it only happens in a closed-source KDE app of the company I work for 
here, I can't give you the code or the binary and plugins.

>or find out where exactly in the malloc it loops?
>
I saw in the debugger that nextp is equal to p->fd and p doesn't get a 
new pointer within the code block of the while statement. That's why it 
loops infinitely. I don't understand what that all means though... Do 
you have an idea?

Ciao
F at lk

>
>
> And first of all, could you run the application in valgrind? This malloc 
>implementation seems to be more vulnerable to heap corruption, so it may be 
>you have a bug somewhere and malloc in glibc gets over it somehow. Your 
>second mail just confirms my suspicion. Most probably you're trying to delete 
>something twice.
>
I should install valgrind...

Cheers,
F at lk



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