arm64: perf: Convert snprintf to sysfs_emit

[ Upstream commit a5740e955540181f4ab8f076cc9795c6bbe4d730 ]

Use sysfs_emit instead of snprintf to avoid buf overrun,because in
sysfs_emit it strictly checks whether buf is null or buf whether
pagesize aligned, otherwise it returns an error.

Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Link: https://lore.kernel.org/r/1621497585-30887-1-git-send-email-tiantao6@hisilicon.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 11852e0..cdb3d45 100644 (file)
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -312,7 +312,7 @@ static ssize_t slots_show(struct device *dev, struct device_attribute *attr,
        struct arm_pmu *cpu_pmu = container_of(pmu, struct arm_pmu, pmu);
        u32 slots = cpu_pmu->reg_pmmir & ARMV8_PMU_SLOTS_MASK;
 
-       return snprintf(page, PAGE_SIZE, "0x%08x\n", slots);
+       return sysfs_emit(page, "0x%08x\n", slots);
 }
 
 static DEVICE_ATTR_RO(slots);