Re: glibc failures on aarch64: (Was Re: [PATCH] add attribute nonstring)

[Florian Weimer <fweimer at redhat dot com>]

On 11/17/2017 01:49 PM, Szabolcs Nagy wrote:
> On 15/11/17 17:58, Steve Ellcey wrote:
> > tst-nss-files-hosts-multi.out:
> >
> > Timed out: killed the child process
>
> i've seen this timeout too (in virtual machine),
> it does 1.5M syscalls a third of which is slow socket syscalls.
>
> i think that's a bit too much, less iterations should be enough.

The buffer code in nss_files (and nss_db) is really sensitive to input 
sizes, and we have seen bugs which are triggered with very specific 
result sizes only, hence the the first loop with the small counts.

The 22222 count is arbitrary, but a fairly large value is needed to make 
the super-linear behavior of the old implementation immediately obvious. 
 An alternative would be to reduce the RLIMIT_AS limit considerably, 
but that might unduly affect architectures which are wasteful with 
address space.

Thanks,
Florian