libio vtable verification failures with multiple libcs

[Florian Weimer]

On 08/10/2016 04:33 PM, Adhemerval Zanella wrote:
>
>
> On 10/08/2016 11:19, Florian Weimer wrote:
>> This is just a heads-up that the Ruby test suite loads libc.so.6 with an absolute path, bypassing AT_PLATFORM directories.  This can lead to multiple libc.so.6 copies within the same process:
>>
>>   <https://bugzilla.redhat.com/show_bug.cgi?id=1361037#c17>

> The only thing that bothers me reading the bug report is the random error
> messages it triggered and the time it took to actually found the culprit.
> Maybe we could help debugging with better warnings.

The error message is:

   “glibc detected an invalid stdio handle”

This is the vtable verification failure message.  It just took me a 
while to figure out that this was a genuine vtable verification failure.

Perhaps we could change the error message to this?

   “glibc detected an invalid stdio handle (vtable verification failure)”

Florian