[RFC PATCH v0 07/19] perf/x86/intel/ds: Check return values of insn decoder functions

Borislav Petkov
2020-11-24T10:20:24Z

branch_type() doesn't need to call the full insn_decode() because it
doesn't need it in all cases thus leave the calls separate.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/events/intel/lbr.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
index 1aadb253d296..0b7d2cc3f001 100644
--- a/arch/x86/events/intel/lbr.c
+++ b/arch/x86/events/intel/lbr.c
@@ -1224,8 +1224,7 @@ static int branch_type(unsigned long from, unsigned long to, int abort)
is64 = kernel_ip((unsigned long)addr) || any_64bit_mode(current_pt_regs());
#endif
insn_init(&insn, addr, bytes_read, is64);
- insn_get_opcode(&insn);
- if (!insn.opcode.got)
+ if (insn_get_opcode(&insn))
return X86_BR_ABORT;

switch (insn.opcode.bytes[0]) {
@@ -1262,8 +1261,7 @@ static int branch_type(unsigned long from, unsigned long to, int abort)
ret = X86_BR_INT;
break;
case 0xe8: /* call near rel */
- insn_get_immediate(&insn);
- if (insn.immediate1.value == 0) {
+ if (insn_get_immediate(&insn) || insn.immediate1.value == 0) {
/* zero length call */
ret = X86_BR_ZERO_CALL;
break;
@@ -1279,7 +1277,9 @@ static int branch_type(unsigned long from, unsigned long to, int abort)
ret = X86_BR_JMP;
break;
case 0xff: /* call near absolute, call far absolute ind */
- insn_get_modrm(&insn);
+ if (insn_get_modrm(&insn))
+ return X86_BR_ABORT;
+
ext = (insn.modrm.bytes[0] >> 3) & 0x7;
switch (ext) {
case 2: /* near ind call */
--
2.21.0