From: Leo Yan <leo.yan@arm.com>
Date: Wed, 17 Sep 2025 17:41:39 +0000 (+0100)
Subject: perf: arm_spe: Prevent overflow in PERF_IDX2OFF()
X-Git-Tag: v6.18-rc1~210^2~5^2~12
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=a29fea30dd93da16652930162b177941abd8c75e;p=thirdparty%2Flinux.git

perf: arm_spe: Prevent overflow in PERF_IDX2OFF()

Cast nr_pages to unsigned long to avoid overflow when handling large
AUX buffer sizes (>= 2 GiB).

Fixes: d5d9696b0380 ("drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension")
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
---

diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c
index 591f72fa03276..fa50645feddad 100644
--- a/drivers/perf/arm_spe_pmu.c
+++ b/drivers/perf/arm_spe_pmu.c
@@ -99,7 +99,8 @@ struct arm_spe_pmu {
 #define to_spe_pmu(p) (container_of(p, struct arm_spe_pmu, pmu))
 
 /* Convert a free-running index from perf into an SPE buffer offset */
-#define PERF_IDX2OFF(idx, buf)	((idx) % ((buf)->nr_pages << PAGE_SHIFT))
+#define PERF_IDX2OFF(idx, buf) \
+	((idx) % ((unsigned long)(buf)->nr_pages << PAGE_SHIFT))
 
 /* Keep track of our dynamic hotplug state */
 static enum cpuhp_state arm_spe_pmu_online;