From abd41f037e1a64543000ed73b42f616d04d92700 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Fri, 12 Jun 2009 22:27:02 -0600 Subject: 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 --- drivers/lguest/lg.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/lguest/lg.h') diff --git a/drivers/lguest/lg.h b/drivers/lguest/lg.h index af92a176697f..6743cf147d97 100644 --- a/drivers/lguest/lg.h +++ b/drivers/lguest/lg.h @@ -139,7 +139,8 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user); #define pgd_pfn(x) (pgd_val(x) >> PAGE_SHIFT) /* interrupts_and_traps.c: */ -void maybe_do_interrupt(struct lg_cpu *cpu); +unsigned int interrupt_pending(struct lg_cpu *cpu); +void try_deliver_interrupt(struct lg_cpu *cpu, unsigned int irq); bool deliver_trap(struct lg_cpu *cpu, unsigned int num); void load_guest_idt_entry(struct lg_cpu *cpu, unsigned int i, u32 low, u32 hi); -- cgit