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Date: Fri, 24 Apr 2009 22:47:06 -0400
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From: Ryan Stone <rysto32@gmail.com>
To: Artem Belevich <fbsdlist@src.cx>
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Cc: freebsd-current@freebsd.org, Ben Kelly <ben@wanderview.com>
Subject: Re: [patch] zfs livelock and thread priorities
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The crash happens because vsnprintf is called twice on the same va_list.
That's not legal.  It happens to work on i386, but it will crash on amd64.
The patch should instead do:

va_list va;
va_start(ap, fmt);
va_copy(va, ap);
vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, va);
vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);

Ryan Stone