x86/insn-eval: Handle insn_get_opcode() failure

is_string_insn() calls insn_get_opcode() that can fail, but does not
handle the failure.

is_string_insn() interface does not allow to communicate an error to the
caller.

Push insn_get_opcode() to the only non-static user of is_string_insn()
and fail it early if insn_get_opcode() fails.

[ dhansen: fix tabs-versus-spaces breakage ]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Joerg Roedel <jroedel@suse.de>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lkml.kernel.org/r/20211130184933.31005-2-kirill.shutemov@linux.intel.com

diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index eb3ccff..1c51e8a 100644 (file)
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -37,8 +37,6 @@ enum reg_type {
  */
 static bool is_string_insn(struct insn *insn)
 {
-       insn_get_opcode(insn);
-
        /* All string instructions have a 1-byte opcode. */
        if (insn->opcode.nbytes != 1)
                return false;
@@ -1405,6 +1403,9 @@ void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs)
        if (!insn || !regs)
                return (void __user *)-1L;
 
+       if (insn_get_opcode(insn))
+               return (void __user *)-1L;
+
        switch (insn->addr_bytes) {
        case 2:
                return get_addr_ref_16(insn, regs);