Re: Still seeing Failed assertion: "p[i] == 0" on armv7 buildworld

bob prohaska <fbsd@www.zefox.net> writes:

> Those files have been overwritten by restarting the buildworld sessions.
> They tend to be large and diffcult to synchronize with the .cpp and .sh
> files generated by the crash. It could be done if it's useful.

At least from the perspective of debugging malloc(3), they'd be useful,
even if the files for reproducing the crash are not synchronized with
the std{err,out} output.  For example, there might be other log messages
generated by jemalloc.

I need a moment to look at the code and step through what it is doing on
FreeBSD but my first guess is that there might just be an incorrect
assumption about committed memory always coming back zeroed.  That
should be true on 64-bit Linux when MADV_DONTNEED is used but not true
if another advice is used like MADV_FREE on either FreeBSD or Linux.  It
is always possible that the kernel is mishanding some memory but I would
like to rule out jemalloc itself before pointing a finger there.