Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753521AbaBRCGp (ORCPT ); Mon, 17 Feb 2014 21:06:45 -0500 Received: from mail-ob0-f177.google.com ([209.85.214.177]:47084 "EHLO mail-ob0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752856AbaBRCGn (ORCPT ); Mon, 17 Feb 2014 21:06:43 -0500 MIME-Version: 1.0 In-Reply-To: <20140217104821.21147.71463.stgit@srivatsabhat.in.ibm.com> References: <20140217104821.21147.71463.stgit@srivatsabhat.in.ibm.com> Date: Tue, 18 Feb 2014 07:36:42 +0530 Message-ID: Subject: Re: [PATCH] cpufreq, powernow-k8: Initialize per-cpu data-structures properly From: Viresh Kumar To: "Srivatsa S. Bhat" , stable@vger.kernel.org Cc: Pierre Ossman , "Rafael J. Wysocki" , "linux-pm@vger.kernel.org" , Linux Kernel Mailing List Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org cc'ing stable for getting this in 3.12 and 3.13 as well.. On 17 February 2014 16:18, Srivatsa S. Bhat wrote: > The powernow-k8 driver maintains a per-cpu data-structure called powernow_data > that is used to perform the frequency transitions. It initializes this data- > structure only for the policy->cpu. So, accesses to this data-structure by > other CPUs results in various problems because they would have been > uninitialized. > > Specifically, if a cpu (!= policy->cpu) invokes the drivers' ->get() function, > it returns 0 as the KHz value, since its per-cpu memory doesn't point to > anything valid. This causes problems during suspend/resume since > cpufreq_update_policy() tries to enforce this (0 KHz) as the current frequency > of the CPU, and this madness gets propagated to adjust_jiffies() as well. > Eventually, lots of things start breaking down, including the r8169 ethernet > card, in one particularly interesting case reported by Pierre Ossman. > > https://bugzilla.kernel.org/show_bug.cgi?id=70311 > > Fix this by initializing the per-cpu data-structures of _all_ the CPUs > in the policy appropriately. > > Cc: stable@vger.kernel.org > Reported-by: Pierre Ossman > Signed-off-by: Srivatsa S. Bhat > --- > > drivers/cpufreq/powernow-k8.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c > index e10b646..6684e03 100644 > --- a/drivers/cpufreq/powernow-k8.c > +++ b/drivers/cpufreq/powernow-k8.c > @@ -1076,7 +1076,7 @@ static int powernowk8_cpu_init(struct cpufreq_policy *pol) > { > struct powernow_k8_data *data; > struct init_on_cpu init_on_cpu; > - int rc; > + int rc, cpu; > > smp_call_function_single(pol->cpu, check_supported_cpu, &rc, 1); > if (rc) > @@ -1140,7 +1140,9 @@ static int powernowk8_cpu_init(struct cpufreq_policy *pol) > pr_debug("cpu_init done, current fid 0x%x, vid 0x%x\n", > data->currfid, data->currvid); > > - per_cpu(powernow_data, pol->cpu) = data; > + /* Point all the CPUs in this policy to the same data */ > + for_each_cpu(cpu, pol->cpus) > + per_cpu(powernow_data, cpu) = data; > > return 0; > > @@ -1155,6 +1157,7 @@ err_out: > static int powernowk8_cpu_exit(struct cpufreq_policy *pol) > { > struct powernow_k8_data *data = per_cpu(powernow_data, pol->cpu); > + int cpu; > > if (!data) > return -EINVAL; > @@ -1165,7 +1168,8 @@ static int powernowk8_cpu_exit(struct cpufreq_policy *pol) > > kfree(data->powernow_table); > kfree(data); > - per_cpu(powernow_data, pol->cpu) = NULL; > + for_each_cpu(cpu, pol->cpus) > + per_cpu(powernow_data, cpu) = NULL; > > return 0; > } > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/