From: Thomas Gleixner <tglx@linutronix.de> To: LKML <linux-kernel@vger.kernel.org> Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@kernel.org>, Sebastian Siewior <bigeasy@linutronix.de>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, "David S. Miller" <davem@davemloft.net>, Fenghua Yu <fenghua.yu@intel.com>, Herbert Xu <herbert@gondor.apana.org.au>, Lai Jiangshan <jiangshanlai@gmail.com>, Len Brown <lenb@kernel.org>, Michael Ellerman <mpe@ellerman.id.au>, "Rafael J. Wysocki" <rjw@rjwysocki.net>, Tejun Heo <tj@kernel.org>, Tony Luck <tony.luck@intel.com>, Viresh Kumar <viresh.kumar@linaro.org>, linux-ia64@vger.kernel.org Subject: [patch V 2 04/13] ia64/sn/hwperf: Replace racy task affinity logic Date: Wed, 12 Apr 2017 22:53:27 +0200 (CEST) [thread overview] Message-ID: <alpine.DEB.2.20.1704122251450.2548@nanos> (raw) In-Reply-To: <20170412201042.421132173@linutronix.de> Subject: ia64/sn/hwperf: Replace racy task affinity logic From: Thomas Gleixner <tglx@linutronix.de> Date: Thu, 06 Apr 2017 14:56:18 +0200 sn_hwperf_op_cpu() which is invoked from an ioctl requires to run code on the requested cpu. This is achieved by temporarily setting the affinity of the calling user space thread to the requested CPU and reset it to the original affinity afterwards. That's racy vs. CPU hotplug and concurrent affinity settings for that thread resulting in code executing on the wrong CPU and overwriting the new affinity setting. Replace it by using work_on_cpu_safe() which guarantees to run the code on the requested CPU or to fail in case the CPU is offline. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: linux-ia64@vger.kernel.org --- V2: Use the work function for real and remove the unused variable (reported by kbuild robot) arch/ia64/sn/kernel/sn2/sn_hwperf.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) Index: b/arch/ia64/sn/kernel/sn2/sn_hwperf.c =================================================================== --- a/arch/ia64/sn/kernel/sn2/sn_hwperf.c +++ b/arch/ia64/sn/kernel/sn2/sn_hwperf.c @@ -598,12 +598,17 @@ static void sn_hwperf_call_sal(void *inf op_info->ret = r; } +static long sn_hwperf_call_sal_work(void *info) +{ + sn_hwperf_call_sal(info); + return 0; +} + static int sn_hwperf_op_cpu(struct sn_hwperf_op_info *op_info) { u32 cpu; u32 use_ipi; int r = 0; - cpumask_t save_allowed; cpu = (op_info->a->arg & SN_HWPERF_ARG_CPU_MASK) >> 32; use_ipi = op_info->a->arg & SN_HWPERF_ARG_USE_IPI_MASK; @@ -629,13 +634,9 @@ static int sn_hwperf_op_cpu(struct sn_hw /* use an interprocessor interrupt to call SAL */ smp_call_function_single(cpu, sn_hwperf_call_sal, op_info, 1); - } - else { - /* migrate the task before calling SAL */ - save_allowed = current->cpus_allowed; - set_cpus_allowed_ptr(current, cpumask_of(cpu)); - sn_hwperf_call_sal(op_info); - set_cpus_allowed_ptr(current, &save_allowed); + } else { + /* Call on the target CPU */ + work_on_cpu_safe(cpu, sn_hwperf_call_sal_work, op_info); } } r = op_info->ret;
WARNING: multiple messages have this Message-ID (diff)
From: Thomas Gleixner <tglx@linutronix.de> To: LKML <linux-kernel@vger.kernel.org> Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@kernel.org>, Sebastian Siewior <bigeasy@linutronix.de>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, "David S. Miller" <davem@davemloft.net>, Fenghua Yu <fenghua.yu@intel.com>, Herbert Xu <herbert@gondor.apana.org.au>, Lai Jiangshan <jiangshanlai@gmail.com>, Len Brown <lenb@kernel.org>, Michael Ellerman <mpe@ellerman.id.au>, "Rafael J. Wysocki" <rjw@rjwysocki.net>, Tejun Heo <tj@kernel.org>, Tony Luck <tony.luck@intel.com>, Viresh Kumar <viresh.kumar@linaro.org>, linux-ia64@vger.kernel.org Subject: [patch V 2 04/13] ia64/sn/hwperf: Replace racy task affinity logic Date: Wed, 12 Apr 2017 20:53:27 +0000 [thread overview] Message-ID: <alpine.DEB.2.20.1704122251450.2548@nanos> (raw) In-Reply-To: <20170412201042.421132173@linutronix.de> Subject: ia64/sn/hwperf: Replace racy task affinity logic From: Thomas Gleixner <tglx@linutronix.de> Date: Thu, 06 Apr 2017 14:56:18 +0200 sn_hwperf_op_cpu() which is invoked from an ioctl requires to run code on the requested cpu. This is achieved by temporarily setting the affinity of the calling user space thread to the requested CPU and reset it to the original affinity afterwards. That's racy vs. CPU hotplug and concurrent affinity settings for that thread resulting in code executing on the wrong CPU and overwriting the new affinity setting. Replace it by using work_on_cpu_safe() which guarantees to run the code on the requested CPU or to fail in case the CPU is offline. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: linux-ia64@vger.kernel.org --- V2: Use the work function for real and remove the unused variable (reported by kbuild robot) arch/ia64/sn/kernel/sn2/sn_hwperf.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) Index: b/arch/ia64/sn/kernel/sn2/sn_hwperf.c =================================--- a/arch/ia64/sn/kernel/sn2/sn_hwperf.c +++ b/arch/ia64/sn/kernel/sn2/sn_hwperf.c @@ -598,12 +598,17 @@ static void sn_hwperf_call_sal(void *inf op_info->ret = r; } +static long sn_hwperf_call_sal_work(void *info) +{ + sn_hwperf_call_sal(info); + return 0; +} + static int sn_hwperf_op_cpu(struct sn_hwperf_op_info *op_info) { u32 cpu; u32 use_ipi; int r = 0; - cpumask_t save_allowed; cpu = (op_info->a->arg & SN_HWPERF_ARG_CPU_MASK) >> 32; use_ipi = op_info->a->arg & SN_HWPERF_ARG_USE_IPI_MASK; @@ -629,13 +634,9 @@ static int sn_hwperf_op_cpu(struct sn_hw /* use an interprocessor interrupt to call SAL */ smp_call_function_single(cpu, sn_hwperf_call_sal, op_info, 1); - } - else { - /* migrate the task before calling SAL */ - save_allowed = current->cpus_allowed; - set_cpus_allowed_ptr(current, cpumask_of(cpu)); - sn_hwperf_call_sal(op_info); - set_cpus_allowed_ptr(current, &save_allowed); + } else { + /* Call on the target CPU */ + work_on_cpu_safe(cpu, sn_hwperf_call_sal_work, op_info); } } r = op_info->ret;
next prev parent reply other threads:[~2017-04-12 20:53 UTC|newest] Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-04-12 20:07 [patch 00/13] sched/treewide: Clean up various racy task affinity issues Thomas Gleixner 2017-04-12 20:07 ` [patch 01/13] ia64/topology: Remove cpus_allowed manipulation Thomas Gleixner 2017-04-12 20:07 ` Thomas Gleixner 2017-04-15 14:15 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 02/13] workqueue: Provide work_on_cpu_safe() Thomas Gleixner 2017-04-13 11:11 ` Dou Liyang 2017-04-13 21:28 ` Thomas Gleixner 2017-04-14 4:18 ` Tejun Heo 2017-04-14 8:54 ` Peter Zijlstra 2017-04-14 9:51 ` Thomas Gleixner 2017-04-14 9:56 ` Peter Zijlstra 2017-04-15 14:16 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 03/13] ia64/salinfo: Replace racy task affinity logic Thomas Gleixner 2017-04-12 20:07 ` Thomas Gleixner 2017-04-15 14:17 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 04/13] ia64/sn/hwperf: " Thomas Gleixner 2017-04-12 20:07 ` Thomas Gleixner 2017-04-12 20:53 ` Thomas Gleixner [this message] 2017-04-12 20:53 ` [patch V 2 " Thomas Gleixner 2017-04-15 14:17 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 05/13] powerpc/smp: Replace open coded " Thomas Gleixner 2017-04-12 20:07 ` Thomas Gleixner 2017-04-13 5:47 ` Michael Ellerman 2017-04-15 14:18 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 06/13] sparc/sysfs: Replace racy " Thomas Gleixner 2017-04-12 20:07 ` Thomas Gleixner 2017-04-13 1:52 ` David Miller 2017-04-13 1:52 ` David Miller 2017-04-13 8:17 ` [patch V2 " Thomas Gleixner 2017-04-13 8:17 ` Thomas Gleixner 2017-04-15 14:18 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 07/13] ACPI/processor: Fix error handling in __acpi_processor_start() Thomas Gleixner 2017-04-15 14:19 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 08/13] ACPI/processor: Replace racy task affinity logic Thomas Gleixner 2017-04-13 11:39 ` Peter Zijlstra 2017-04-13 12:01 ` Thomas Gleixner 2017-04-13 12:52 ` Peter Zijlstra 2017-04-15 14:19 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 09/13] cpufreq/ia64: " Thomas Gleixner 2017-04-12 20:55 ` [patch V2 " Thomas Gleixner 2017-04-15 14:20 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-13 2:42 ` [patch 09/13] " Viresh Kumar 2017-04-12 20:07 ` [patch 10/13] cpufreq/sh: " Thomas Gleixner 2017-04-13 2:46 ` Viresh Kumar 2017-04-15 14:20 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 11/13] cpufreq/sparc-us3: " Thomas Gleixner 2017-04-13 2:48 ` Viresh Kumar 2017-04-15 14:21 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-12 20:07 ` [patch 12/13] cpufreq/sparc-us2e: " Thomas Gleixner 2017-04-13 2:50 ` Viresh Kumar 2017-04-13 8:19 ` [patch V2 " Thomas Gleixner 2017-04-13 8:22 ` [patch V3 " Thomas Gleixner 2017-04-15 14:21 ` [tip:sched/core] " tip-bot for Thomas Gleixner 2017-04-13 14:50 ` [patch V2 12/13] " David Miller 2017-04-12 20:07 ` [patch 13/13] crypto: n2 - " Thomas Gleixner 2017-04-13 4:56 ` Herbert Xu 2017-04-13 8:20 ` [patch V2 " Thomas Gleixner 2017-04-13 14:51 ` David Miller 2017-04-15 14:22 ` [tip:sched/core] crypto: N2 " tip-bot for Thomas Gleixner 2017-04-13 9:02 ` [patch 00/13] sched/treewide: Clean up various racy task affinity issues Peter Zijlstra
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=alpine.DEB.2.20.1704122251450.2548@nanos \ --to=tglx@linutronix.de \ --cc=benh@kernel.crashing.org \ --cc=bigeasy@linutronix.de \ --cc=davem@davemloft.net \ --cc=fenghua.yu@intel.com \ --cc=herbert@gondor.apana.org.au \ --cc=jiangshanlai@gmail.com \ --cc=lenb@kernel.org \ --cc=linux-ia64@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=mingo@kernel.org \ --cc=mpe@ellerman.id.au \ --cc=peterz@infradead.org \ --cc=rjw@rjwysocki.net \ --cc=tj@kernel.org \ --cc=tony.luck@intel.com \ --cc=viresh.kumar@linaro.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.