fadvise gclibc vs uclibc

[Carmelo AMOROSO]

Bernhard Reutner-Fischer wrote:
> Hi,
> 
> On Mon, Sep 08, 2008 at 05:35:24PM -0400, Corinna Schultz wrote:
>> I noticed this difference between glibc and uclibc, in the fadvise  
>> code (I'm trying to track down a bug on a ppc32 machine).
>>
>> Why the difference in the number of arguments? I don't know too much  
>> about the system call mechanism, so this may be something obvious :)
> 
> There were historically bugs in that area IIRC due to the kernel lagging
> a bit behind. Look for e.g. ASSUME_FADVISE64_64_SYSCALL and look at e.g.
> http://sourceware.org/bugzilla/show_bug.cgi?id=781
> Tested patches are welcome.
> 
> HTH,
> 
Hi Corinna,
a colleague of mine is right now working to produce a patch for 
posix_fadvise to fix all LTP tests using posix_fadvise[64].

Indeed LTP tests expect that, when posix_fadvise[64] fails,
it should return as return value an error code (-errno) instead
of simply setting properly errno and returning -1.

Man pages are not clear on this behaviour, it depends on POSIX standards
it want be compliant to, so a clear understanding it's required
before closing this issues.

Anyway, some real bugs have been discovered in uclibc implementation
and will be fixed asap.

As Bernhard said, tested patches are welcome.

Cheers,
Carmelo

> PS: since you seem to be interrested in powerpc, let me point you to
> the heads-up that we will remove problematic parts of libm for powerpc,
> in case you have not seen it:
> http://uclibc.org/lists/uclibc/2008-September/019988.html
> If nobody fixes these issues by either getting properly licensed impls
> or by reimplementing the problematic bits under an acceptable license,
> then the powerpc specific hunks of libm will be removed from svn.
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