From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELs1vjohs7ad9oeRlNmebd6iNR2ywoa+Td5MPI4xGQHd+H57tAarzCAgd3sL1p0olX33A+/u ARC-Seal: i=1; a=rsa-sha256; t=1521800298; cv=none; d=google.com; s=arc-20160816; b=vKP6nXFXFDc6krXPOArLHJVmlR4qe/F8hQjJIDAgOoeMxbFWJAlHlvmuZB3HyLteYt z9ss4Rd1fvB/2qGnMuWWAhGGdeEd686ah7UjmCZFRBm5/lDZkJS3lL7kUuqipWSPt7HQ /2UsWL+0Vxol2tbBEhYFn190DYLLPnwKzFuJ5WDwjZ50Cm7ARohuf9V5lmzxEAzkgvm+ MeBqY4akoOKalgrJbvvVDPogDjjcNXoOZlQyAoXnOr5/1Z3O8aDV6qf0TXRQqWgFPkMe adAr3Jt2Bbep4Laev0/BWTrkKI73c73l0/1378H0qZw8i83M12uELpEza6zmkCI9I3BH H0sA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=WFdn2ljVVIt+c8nl4sE+Fw6WRa7AtfBCZmFSCHPjMAU=; b=k4cH4r44XDZuyqdn6K3wPYsOdirwjAzCrBp6f29sIvHchEMJfgI9DdM/B9Fj/Qn3yC nJ+9gco8wvU6V3LKPN7vhlRsxO9YPFtAduYKrS7Yn396dxDy5+TgB+KAsDPyAuzJNh9/ m+9YjqZ/nSxHP/HQomss47wMLJMm9QWTlIaWGtQH+2MSpaFltsWLxEtNznBrCsxHCe0Q Pfw7+2BcqmWmxXFjsNxAfvm1lgDXJhTyxUbMnOwOsc7izXWiEGhxrXjZlnTg4tZvzf04 2N8ttI01iEjbRFVwq1fsqPeDALHbswm3Q7NW+L+v0cwbiIGYkbPPtS1Bn7N2rVqo+Q8W IGJg== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thomas Gleixner , Viresh Kumar , Fenghua Yu , Tony Luck , Herbert Xu , "Rafael J. Wysocki" , Peter Zijlstra , Benjamin Herrenschmidt , Sebastian Siewior , linux-pm@vger.kernel.org, Lai Jiangshan , Michael Ellerman , Tejun Heo , "David S. Miller" , Len Brown , Sasha Levin Subject: [PATCH 3.18 05/47] cpufreq/sh: Replace racy task affinity logic Date: Fri, 23 Mar 2018 10:54:56 +0100 Message-Id: <20180323094248.347689835@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180323094248.117679641@linuxfoundation.org> References: <20180323094248.117679641@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1595722445513393814?= X-GMAIL-MSGID: =?utf-8?q?1595723269971198382?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner [ Upstream commit 205dcc1ecbc566cbc20acf246e68de3b080b3ecf ] The target() callback must run on the affected cpu. This is achieved by temporarily setting the affinity of the calling thread to the requested CPU and reset it to the original affinity afterwards. That's racy vs. concurrent affinity settings for that thread resulting in code executing on the wrong CPU. Replace it by work_on_cpu(). All call pathes which invoke the callbacks are already protected against CPU hotplug. Signed-off-by: Thomas Gleixner Acked-by: Viresh Kumar Cc: Fenghua Yu Cc: Tony Luck Cc: Herbert Xu Cc: "Rafael J. Wysocki" Cc: Peter Zijlstra Cc: Benjamin Herrenschmidt Cc: Sebastian Siewior Cc: linux-pm@vger.kernel.org Cc: Lai Jiangshan Cc: Michael Ellerman Cc: Tejun Heo Cc: "David S. Miller" Cc: Len Brown Link: http://lkml.kernel.org/r/20170412201042.958216363@linutronix.de Signed-off-by: Thomas Gleixner Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/cpufreq/sh-cpufreq.c | 45 +++++++++++++++++++++++++------------------ 1 file changed, 27 insertions(+), 18 deletions(-) --- a/drivers/cpufreq/sh-cpufreq.c +++ b/drivers/cpufreq/sh-cpufreq.c @@ -30,54 +30,63 @@ static DEFINE_PER_CPU(struct clk, sh_cpuclk); +struct cpufreq_target { + struct cpufreq_policy *policy; + unsigned int freq; +}; + static unsigned int sh_cpufreq_get(unsigned int cpu) { return (clk_get_rate(&per_cpu(sh_cpuclk, cpu)) + 500) / 1000; } -/* - * Here we notify other drivers of the proposed change and the final change. - */ -static int sh_cpufreq_target(struct cpufreq_policy *policy, - unsigned int target_freq, - unsigned int relation) +static long __sh_cpufreq_target(void *arg) { - unsigned int cpu = policy->cpu; + struct cpufreq_target *target = arg; + struct cpufreq_policy *policy = target->policy; + int cpu = policy->cpu; struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu); - cpumask_t cpus_allowed; struct cpufreq_freqs freqs; struct device *dev; long freq; - cpus_allowed = current->cpus_allowed; - set_cpus_allowed_ptr(current, cpumask_of(cpu)); - - BUG_ON(smp_processor_id() != cpu); + if (smp_processor_id() != cpu) + return -ENODEV; dev = get_cpu_device(cpu); /* Convert target_freq from kHz to Hz */ - freq = clk_round_rate(cpuclk, target_freq * 1000); + freq = clk_round_rate(cpuclk, target->freq * 1000); if (freq < (policy->min * 1000) || freq > (policy->max * 1000)) return -EINVAL; - dev_dbg(dev, "requested frequency %u Hz\n", target_freq * 1000); + dev_dbg(dev, "requested frequency %u Hz\n", target->freq * 1000); freqs.old = sh_cpufreq_get(cpu); freqs.new = (freq + 500) / 1000; freqs.flags = 0; - cpufreq_freq_transition_begin(policy, &freqs); - set_cpus_allowed_ptr(current, &cpus_allowed); + cpufreq_freq_transition_begin(target->policy, &freqs); clk_set_rate(cpuclk, freq); - cpufreq_freq_transition_end(policy, &freqs, 0); + cpufreq_freq_transition_end(target->policy, &freqs, 0); dev_dbg(dev, "set frequency %lu Hz\n", freq); - return 0; } +/* + * Here we notify other drivers of the proposed change and the final change. + */ +static int sh_cpufreq_target(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation) +{ + struct cpufreq_target data = { .policy = policy, .freq = target_freq }; + + return work_on_cpu(policy->cpu, __sh_cpufreq_target, &data); +} + static int sh_cpufreq_verify(struct cpufreq_policy *policy) { struct clk *cpuclk = &per_cpu(sh_cpuclk, policy->cpu);