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Date: Fri, 7 Dec 2018 21:35:32 +0100
From: Markus Wichmann <nullplan@....net>
To: musl@...ts.openwall.com
Subject: Re: aio_cancel segmentation fault for in progress write
 requests

On Fri, Dec 07, 2018 at 01:13:44PM -0600, A. Wilcox wrote:
> So, my best theory is that running inside a debugger (gdb, valgrind)
> makes it slow enough that it no longer races.

Two ideas to investigate further. 1: Produce a coredump ("ulimit -c
unlimited"). That won't interfere with timing, but I have no clue if
coredumps work with multithreading.

2: Might I suggest installing a SIGSEGV handler? If you have libunwind,
you can create a backtrace from inside the handler. And even if not, you
can at least print the exception PC, which would help a ton already.

Only, don't return from that handler. Either _exit(), or better yet,
restore the default handler, then kill yourself with SIGSEGV.

Ciao,
Markus

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