kprobes/x86: Return correct length in __copy_instruction()

[cascardo/linux.git] / arch / x86 / kernel / kprobes / core.c

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 4e3d5a9..03189d8 100644 (file)
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -354,6 +354,7 @@ int __copy_instruction(u8 *dest, u8 *src)
 {
        struct insn insn;
        kprobe_opcode_t buf[MAX_INSN_SIZE];
+       int length;
        unsigned long recovered_insn =
                recover_probed_instruction(buf, (unsigned long)src);
 
@@ -361,16 +362,18 @@ int __copy_instruction(u8 *dest, u8 *src)
                return 0;
        kernel_insn_init(&insn, (void *)recovered_insn, MAX_INSN_SIZE);
        insn_get_length(&insn);
+       length = insn.length;
+
        /* Another subsystem puts a breakpoint, failed to recover */
        if (insn.opcode.bytes[0] == BREAKPOINT_INSTRUCTION)
                return 0;
-       memcpy(dest, insn.kaddr, insn.length);
+       memcpy(dest, insn.kaddr, length);
 
 #ifdef CONFIG_X86_64
        if (insn_rip_relative(&insn)) {
                s64 newdisp;
                u8 *disp;
-               kernel_insn_init(&insn, dest, insn.length);
+               kernel_insn_init(&insn, dest, length);
                insn_get_displacement(&insn);
                /*
                 * The copied instruction uses the %rip-relative addressing
@@ -394,7 +397,7 @@ int __copy_instruction(u8 *dest, u8 *src)
                *(s32 *) disp = (s32) newdisp;
        }
 #endif
-       return insn.length;
+       return length;
 }
 
 static int arch_copy_kprobe(struct kprobe *p)