because a client might not handle resize, rio would try to move ther
window offsceen after 750 ms. however, it does this by window name,
which could have been reassigned by another concurrent rio, causing the
wrong window to disappear.
now we always move the window offscreen before freeimage(). this way we
are sure to still have the right reference to the original window.
segclock() has to be called from hzclock(), otherwise
only processes running on cpu0 would catche the interrupt
and the time delta would be wrong.
lock the segment when allocating Seg->profile as
profile ctl might be issued from multiple processes.
Proc->debug qlock is not sufficient.
Seg->profile can never be freed or reallocated once
set as the timer interrupt accesses it without any
locking.
to read the value of the stack pointer register, snap
used Machdata->szreg to determine the width of the
SP register in the Ureg structure. however, the value
does not match the Ureg.sp type for a number of architectures
(mips2, amd64) and it is unclear if this was an oversight
as it is rarely used (snap is indeed the only user) or
if it was intended for a different purpose.
so we use szaddr instead which matches the stack pointer
width in the Ureg and fixes the truncated stack issue on
amd64.
this can happen when the on the final sync when the mailbox
is being freed:
freembox -> mboxdecref -> syncmbox -> wridxfile -> pridx -> insurecache -> msgincref
syncmbox() used to enter the mailbox into the hash tree to
update the qid.vers. this is wrong when we are doing the final
sync before freeing the mailbox as the hash reference has already
been removed by freemailbox().
also avoid adding hash entries for mails for the about to be
freed mailbox in cachehash().
