On Fri, Feb 28, 2014 at 04:33:40PM +0100, Jiri Olsa wrote:
While I like the idea of just pushing up the CR2 read; the below does
the read too late still, exception_enter() also has a tracepoint in.
> @@ -1267,9 +1269,18 @@ dotraplinkage void __kprobes
> trace_do_page_fault(struct pt_regs *regs, unsigned long error_code)
> {
> enum ctx_state prev_state;
> + unsigned long address;
>
> prev_state = exception_enter();
> +
> + /*
> + * The tracepoint processing could trigger another page
> + * fault (user space callchain reading) and destroy the
> + * original cr2 value, so read the faulting address now.
> + */
> + address = read_cr2();
> +
> trace_page_fault_entries(regs, error_code);
> - __do_page_fault(regs, error_code);
> + __do_page_fault(regs, error_code, address);
> exception_exit(prev_state);
> }
> --
> 1.7.11.7
>
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