From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tim Deegan Subject: [PATCH 5/9] cpufreq: avoid integer overflows. Date: Thu, 12 Sep 2013 13:15:26 +0100 Message-ID: <1378988130-24172-6-git-send-email-tim@xen.org> References: <1378988130-24172-1-git-send-email-tim@xen.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1378988130-24172-1-git-send-email-tim@xen.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xen.org Cc: Liu Jinsong , Jan Beulich List-Id: xen-devel@lists.xenproject.org The def_sampling_rate() one is, I think, a real bug. The others were spotted at the same time and are probably not bugs until we start dealing with 40GHz CPus. Coverity CID 1055682 Coverity CID 1055683 Signed-off-by: Tim Deegan Cc: Jan Beulich Cc: Liu Jinsong --- xen/drivers/cpufreq/cpufreq_ondemand.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/xen/drivers/cpufreq/cpufreq_ondemand.c b/xen/drivers/cpufreq/cpufreq_ondemand.c index b3f9ab8..7fdba03 100644 --- a/xen/drivers/cpufreq/cpufreq_ondemand.c +++ b/xen/drivers/cpufreq/cpufreq_ondemand.c @@ -144,7 +144,7 @@ static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info) } /* Check for frequency increase */ - if (max_load_freq > dbs_tuners_ins.up_threshold * policy->cur) { + if (max_load_freq > (uint64_t) dbs_tuners_ins.up_threshold * policy->cur) { /* if we are already at full speed then break out early */ if (policy->cur == max) return; @@ -162,7 +162,8 @@ static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info) * can support the current CPU usage without triggering the up * policy. To be safe, we focus 10 points under the threshold. */ - if (max_load_freq < (dbs_tuners_ins.up_threshold - 10) * policy->cur) { + if (max_load_freq + < (uint64_t) (dbs_tuners_ins.up_threshold - 10) * policy->cur) { uint64_t freq_next; freq_next = max_load_freq / (dbs_tuners_ins.up_threshold - 10); @@ -246,7 +247,7 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event) * is used for first time */ if ((dbs_enable == 1) && !dbs_tuners_ins.sampling_rate) { - def_sampling_rate = policy->cpuinfo.transition_latency * + def_sampling_rate = (uint64_t) policy->cpuinfo.transition_latency * DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; if (def_sampling_rate < MIN_STAT_SAMPLING_RATE) -- 1.7.10.4