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save cpus.intena in sched(), so we get the right EFLAGS.IF value once a

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timer-preempted kernel thread resumes execution in trap() after yield().
otherwise the kernel could get an arbitrary number of nested timer intrs.
This commit is contained in:
kolya 2008-10-15 05:01:39 +00:00
parent 15ce79de14
commit 228e500a0c
1 changed files with 5 additions and 1 deletions
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6
proc.c
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@ -207,7 +207,7 @@ scheduler(void)
c = &cpus[cpu()];
for(;;){
// Enable interrupts on this processor.
// Enable interrupts on this processor, in lieu of saving intena.
sti();
// Loop over process table looking for process to run.
@ -240,6 +240,8 @@ scheduler(void)
void
sched(void)
{
int intena;
if(read_eflags()&FL_IF)
panic("sched interruptible");
if(cp->state == RUNNING)
@ -249,7 +251,9 @@ sched(void)
if(cpus[cpu()].ncli != 1)
panic("sched locks");
intena = cpus[cpu()].intena;
swtch(&cp->context, &cpus[cpu()].context);
cpus[cpu()].intena = intena;
}
// Give up the CPU for one scheduling round.