[tip: x86/core] perf/x86/intel/ds: Check insn_get_length() retval

["tip-bot2 for Borislav Petkov" <tip-bot2@linutronix.de>]

The following commit has been merged into the x86/core branch of tip:

Commit-ID:     2ff49881d606d5e0d5b27cb6066c8a18689bd341
Gitweb:        https://git.kernel.org/tip/2ff49881d606d5e0d5b27cb6066c8a18689bd341
Author:        Borislav Petkov <bp@suse.de>
AuthorDate:    Fri, 06 Nov 2020 16:33:34 +01:00
Committer:     Borislav Petkov <bp@suse.de>
CommitterDate: Mon, 15 Mar 2021 11:20:29 +01:00

perf/x86/intel/ds: Check insn_get_length() retval

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@suse.de>
Link: https://lkml.kernel.org/r/20210304174237.31945-8-bp@alien8.de
---
 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 7ebae18..cdd195a 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;