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    Subject[PATCH v8 09/28] x86/insn-eval: Do not BUG on invalid register type
    Date
    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 <bp@suse.de>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Dave Hansen <dave.hansen@linux.intel.com>
    Cc: Adam Buchbinder <adam.buchbinder@gmail.com>
    Cc: Colin Ian King <colin.king@canonical.com>
    Cc: Lorenzo Stoakes <lstoakes@gmail.com>
    Cc: Qiaowei Ren <qiaowei.ren@intel.com>
    Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
    Cc: Masami Hiramatsu <mhiramat@kernel.org>
    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Kees Cook <keescook@chromium.org>
    Cc: Thomas Garnier <thgarnie@google.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Dmitry Vyukov <dvyukov@google.com>
    Cc: Ravi V. Shankar <ravi.v.shankar@intel.com>
    Cc: x86@kernel.org
    Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
    ---
    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");
    + return -EINVAL;
    }

    if (regno >= nr_registers) {
    --
    2.13.0
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