linux-kernel - [PATCH v2 07/21] perf/x86/intel/ds: Check insn_get

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Message-Id: <20210224110233.19715-8-bp@alien8.de>
Date:   Wed, 24 Feb 2021 12:02:19 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     X86 ML <x86@...nel.org>
Cc:     Masami Hiramatsu <mhiramat@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH v2 07/21] perf/x86/intel/ds: Check insn_get_length() retval

From: Borislav Petkov <bp@...e.de>

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@...e.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 67dbc91bccfe..c1c710f6057b 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -1265,14 +1265,13 @@ 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