Fixes an issue in kernel build where the user addresses passed
to accept() would be accessed when the wrong MMU mappings were
active. A crash would manifest when attempting to accept() on a
TCP server socket for instance under significant load. The accept
event handler would be called by the HP worker upon client
connection. At this point, accept_tcpsender() would attempt to
write to `addr` resulting in a page fault. Reproducibility would
depend on the current system load (num tasks or CPU stress) but
in loaded environments, it would crash almost 100% of the times.
It should be noted that Linux does this the other way around: it
operates on kernel stack allocated data and once done, it copies
them to user. This can also be a viable alternative, albeit with
one extra copy and a little extra memory.
Signed-off-by: George Poulios <gpoulios@census-labs.com>
884b4604c2