[PATCHv3 1/4] x86/insn-eval: Handle insn_get_opcode() failure

Kirill A. Shutemov
2021-11-03T15:46:34Z

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.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
arch/x86/lib/insn-eval.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index a1d24fdc07cf..8b7c2f2ea8f4 100644
--- 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);
--
2.32.0