I've been encountering this bus error for months now - I think since early this year. It only occurs as described with http authentication and is always 'resolved' by a restart of apache. The backtrace always reveals memset() as the final stack entry, yet the servers rarely have more than 50% of their memory in use.
For quite some time I thought this was a problem with file descriptors hitting their limit and simply being reported as a memory allocation error incorrectly (or that this was using a memory mapped file). Is it possible this is still the case? Keep in mind that I did recompile Apache with considerably higher file descriptors as the limit (65536) and the problem remained.
A few days ago I updated Apache to 2.2.21 from the atomic-testing repo on both servers where this problem was occurring since it was suggested earlier in the thread that the update might resolve the problem. As of this afternoon the segfaults began to re-appear while running 2.2.21. The top of the stack trace looks pretty much identical to those reported earlier in this thread with the indication that the problem is in apr.
#0 0xb7be1697 in memset () from /lib/libc.so.6
#1 0xb7eaf7ab in apr_password_validate () from /usr/lib/libaprutil-1.so.0
What version of apr is 2.2.21 in atomic-testing built against? Does changing my system installed version of apr have any effect on this bug? (My assumption thus far has been that the version of apr installed only affects applications built using apr on that server).
Since there are already stack traces here for this issue, is there anything more I can provide to help resolve this problem? Someone mentioned there being an existing report for this in the apache bugtracker - is this confirmed, and if so, where is it?
Thanks for the help