Re: [PATCH v4 2/5] x86/msr: Carry on after a non-"safe" MSR access fails without !panic_on_oops

[Linus Torvalds]

On Mon, Mar 14, 2016 at 11:24 AM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
>
> The code in my queue is, literally:
>
> bool ex_handler_rdmsr_unsafe(const struct exception_table_entry *fixup,
>                  struct pt_regs *regs, int trapnr)
> {
>     WARN_ONCE(1, "unchecked MSR access error: RDMSR from 0x%x",
>           (unsigned int)regs->cx);
>
>     /* Pretend that the read succeeded and returned 0. */
>     regs->ip = ex_fixup_addr(fixup);
>     regs->ax = 0;
>     regs->dx = 0;
>     return true;
> }
> EXPORT_SYMBOL(ex_handler_rdmsr_unsafe);

I guess I can live with this, as long as we also extend the
early-fault handling to work with the special exception handlers.

And as long as people start understanding that killing the machine is
a bad bad bad thing. It's a debugging nightmare.

               Linus