[PATCH v3 07/21] perf/x86/intel/ds: Check insn_get_length() retval

From: Borislav Petkov
Date: Thu Mar 04 2021 - 12:46:55 EST


From: Borislav Petkov <bp@xxxxxxx>

intel_pmu_pebs_fixup_ip() needs only the insn length so use the
appropriate helper instead of a full decode. A full decode differs only
in running insn_complete() on the decoded insn but that is not needed
here.

Signed-off-by: Borislav Petkov <bp@xxxxxxx>
---
arch/x86/events/intel/ds.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 7ebae1826403..cdd195a3804e 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -1353,14 +1353,13 @@ static int intel_pmu_pebs_fixup_ip(struct pt_regs *regs)
is_64bit = kernel_ip(to) || any_64bit_mode(regs);
#endif
insn_init(&insn, kaddr, size, is_64bit);
- insn_get_length(&insn);
+
/*
- * Make sure there was not a problem decoding the
- * instruction and getting the length. This is
- * doubly important because we have an infinite
- * loop if insn.length=0.
+ * Make sure there was not a problem decoding the instruction.
+ * This is doubly important because we have an infinite loop if
+ * insn.length=0.
*/
- if (!insn.length)
+ if (insn_get_length(&insn))
break;

to += insn.length;
--
2.29.2