On Fri, Aug 18, 2017 at 05:27:50PM -0700, Ricardo Neri wrote:
> We are not in a critical failure path. The invalid register type is caused
> when trying to decode invalid instruction bytes from a user-space program.
> Thus, simply print an error message. To prevent this warning from being
> abused from user space programs, use the rate-limited variant of pr_err().
> 
> Cc: Borislav Petkov <[email protected]>
> Cc: Andy Lutomirski <[email protected]>
> Cc: Dave Hansen <[email protected]>
> Cc: Adam Buchbinder <[email protected]>
> Cc: Colin Ian King <[email protected]>
> Cc: Lorenzo Stoakes <[email protected]>
> Cc: Qiaowei Ren <[email protected]>
> Cc: Arnaldo Carvalho de Melo <[email protected]>
> Cc: Masami Hiramatsu <[email protected]>
> Cc: Adrian Hunter <[email protected]>
> Cc: Kees Cook <[email protected]>
> Cc: Thomas Garnier <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Cc: Dmitry Vyukov <[email protected]>
> Cc: Ravi V. Shankar <[email protected]>
> Cc: [email protected]
> Signed-off-by: Ricardo Neri <[email protected]>
> ---
>  arch/x86/lib/insn-eval.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
> index 2bb8303ba92f..3919458fecbf 100644
> --- a/arch/x86/lib/insn-eval.c
> +++ b/arch/x86/lib/insn-eval.c
> @@ -5,6 +5,7 @@
>   */
>  #include <linux/kernel.h>
>  #include <linux/string.h>
> +#include <linux/ratelimit.h>
>  #include <asm/inat.h>
>  #include <asm/insn.h>
>  #include <asm/insn-eval.h>
> @@ -85,9 +86,8 @@ static int get_reg_offset(struct insn *insn, struct pt_regs 
> *regs,
>               break;
>  
>       default:
> -             pr_err("invalid register type");
> -             BUG();
> -             break;
> +             pr_err_ratelimited("insn: x86: invalid register type");

Also, I meant to add it to pr_fmt. Feel free to merge this hunk ontop of
yours:

---
diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index 3919458fecbf..d46034ddfbb7 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -10,6 +10,9 @@
 #include <asm/insn.h>
 #include <asm/insn-eval.h>
 
+#undef pr_fmt
+#define pr_fmt(fmt) "insn: " fmt
+
 enum reg_type {
        REG_TYPE_RM = 0,
        REG_TYPE_INDEX,
@@ -86,7 +89,7 @@ static int get_reg_offset(struct insn *insn, struct pt_regs 
*regs,
                break;
 
        default:
-               pr_err_ratelimited("insn: x86: invalid register type");
+               pr_err_ratelimited("invalid register type: %d\n", type);
                return -EINVAL;
        }
 

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 
(AG Nürnberg)
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