lguest: fix race in halt code
authorRusty Russell <rusty@rustcorp.com.au>
Sat, 13 Jun 2009 04:27:02 +0000 (22:27 -0600)
committerRusty Russell <rusty@rustcorp.com.au>
Fri, 12 Jun 2009 12:57:02 +0000 (21:57 +0930)
commitabd41f037e1a64543000ed73b42f616d04d92700
treed9013e66f4d8fc66fc92ce0587f8d126e156b253
parentebf9a5a99c1a464afe0b4dfa64416fc8b273bc5c
lguest: fix race in halt code

When the Guest does the LHCALL_HALT hypercall, we go to sleep, expecting
that a timer or the Waker will wake_up_process() us.

But we do it in a stupid way, leaving a classic missing wakeup race.

So split maybe_do_interrupt() into interrupt_pending() and
try_deliver_interrupt(), and check maybe_do_interrupt() and the
"break_out" flag before calling schedule.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
drivers/lguest/core.c
drivers/lguest/interrupts_and_traps.c
drivers/lguest/lg.h