From: Jean Delvare Date: Tue, 5 Nov 2024 08:52:53 +0000 (+0100) Subject: perf/x86/amd/uncore: Avoid a false positive warning about snprintf truncation in... X-Git-Tag: v6.13-rc1~179^2~6 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2e71e8bc6f02275a67bcb882779ab6d21abc68c4;p=thirdparty%2Flinux.git perf/x86/amd/uncore: Avoid a false positive warning about snprintf truncation in amd_uncore_umc_ctx_init Fix the following warning: CC [M] arch/x86/events/amd/uncore.o arch/x86/events/amd/uncore.c: In function ‘amd_uncore_umc_ctx_init’: arch/x86/events/amd/uncore.c:951:52: warning: ‘%d’ directive output may be truncated writing between 1 and 10 bytes into a region of size 8 [-Wformat-truncation=] snprintf(pmu->name, sizeof(pmu->name), "amd_umc_%d", index); ^~ arch/x86/events/amd/uncore.c:951:43: note: directive argument in the range [0, 2147483647] snprintf(pmu->name, sizeof(pmu->name), "amd_umc_%d", index); ^~~~~~~~~~~~ arch/x86/events/amd/uncore.c:951:4: note: ‘snprintf’ output between 10 and 19 bytes into a destination of size 16 snprintf(pmu->name, sizeof(pmu->name), "amd_umc_%d", index); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ As far as I can see, there can't be more than UNCORE_GROUP_MAX (256) groups and each group can't have more than 255 PMU, so the number printed by this %d can't exceed 65279, that's only 5 digits and would fit into the buffer. So it's a false positive warning. But we can make the compiler happy by declaring index as a 16-bit number. Signed-off-by: Jean Delvare Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Sandipan Das Link: https://lore.kernel.org/r/20241105095253.18f34b4d@endymion.delvare --- diff --git a/arch/x86/events/amd/uncore.c b/arch/x86/events/amd/uncore.c index 0bfde2ea5cb8c..49c26ce2b1152 100644 --- a/arch/x86/events/amd/uncore.c +++ b/arch/x86/events/amd/uncore.c @@ -916,7 +916,8 @@ int amd_uncore_umc_ctx_init(struct amd_uncore *uncore, unsigned int cpu) u8 group_num_pmcs[UNCORE_GROUP_MAX] = { 0 }; union amd_uncore_info info; struct amd_uncore_pmu *pmu; - int index = 0, gid, i; + int gid, i; + u16 index = 0; if (pmu_version < 2) return 0; @@ -948,7 +949,7 @@ int amd_uncore_umc_ctx_init(struct amd_uncore *uncore, unsigned int cpu) for_each_set_bit(gid, gmask, UNCORE_GROUP_MAX) { for (i = 0; i < group_num_pmus[gid]; i++) { pmu = &uncore->pmus[index]; - snprintf(pmu->name, sizeof(pmu->name), "amd_umc_%d", index); + snprintf(pmu->name, sizeof(pmu->name), "amd_umc_%hu", index); pmu->num_counters = group_num_pmcs[gid] / group_num_pmus[gid]; pmu->msr_base = MSR_F19H_UMC_PERF_CTL + i * pmu->num_counters * 2; pmu->rdpmc_base = -1;