linux(4): Replace casuword32 by casueword32 in handle_futex_death().

[kib]

sys/compat/linux/linux_futex.c

1001

This is fine as the step, but please look at 30b3018d48e4441083b483

[dchagin]

sys/compat/linux/linux_futex.c

1001

sure, did I understand correctly that on ll/sc architectures casueword can fails as there are two operations,
and exceptional events between this operations can lead the second operation (store-conditional) to spuriously fail.
So before repeating we need a check for stops etc...?
If so, I need to revise all of new futex code ))

[kib]

sys/compat/linux/linux_futex.c

1001

Right. Generally casueword is allowed to spuriously fail on all arches, same as cmpset/fcmpset.

[dchagin]

Follow the r349951 (30b3018d), add check to react to stops and requests
to terminate between retries.

[kib]

sys/compat/linux/linux_futex.c

1002

error != 0