RE: Oops with tip/x86/fpu

[Yu, Fenghua]

> From: Oleg Nesterov [mailto:oleg@xxxxxxxxxx]
> Sent: Thursday, March 05, 2015 10:22 AM
> 
> On 03/05, Oleg Nesterov wrote:
> >
> 
> Does it trigger something else on your machine?
> 
> Oleg.
> 
> #include <stdio.h>
> #include <signal.h>
> #include <unistd.h>
> #include <ucontext.h>
> 
> void sighup(int sig, siginfo_t *info, void *ctxt) {
> 	struct ucontext *uctxt = ctxt;
> 	struct sigcontext *sctxt = (void*)&uctxt->uc_mcontext;
> 
> 	printf("SIGHUP! %p\n", sctxt->fpstate);
> 	sctxt->fpstate = (void *)1;

sctxt->fpstate=(void *)1 changes the fpstate pointer in the sigcontext. It will generate segfault and bad frame info in kernel.

This is expected behavior, right? Is this still a valid test?

Thanks.

-Fenghua
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