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Groups > linux.kernel > #1624076
| From | tip-bot for Thomas Gleixner <tipbot@zytor.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [tip:sched/core] powerpc/smp: Replace open coded task affinity logic |
| Date | 2017-04-15 16:30 +0200 |
| Message-ID | <twwS5-7Dd-3@gated-at.bofh.it> (permalink) |
| References | <tvx3Q-QV-37@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
Commit-ID: 6d11b87d55eb75007a3721c2de5938f5bbf607fb
Gitweb: http://git.kernel.org/tip/6d11b87d55eb75007a3721c2de5938f5bbf607fb
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Wed, 12 Apr 2017 22:07:31 +0200
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sat, 15 Apr 2017 12:20:54 +0200
powerpc/smp: Replace open coded task affinity logic
Init task invokes smp_ops->setup_cpu() from smp_cpus_done(). Init task can
run on any online CPU at this point, but the setup_cpu() callback requires
to be invoked on the boot 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.
That's actually not a problem in this context as neither CPU hotplug nor
affinity settings can happen, but the access to task_struct::cpus_allowed
is about to restricted.
Replace it with a call to work_on_cpu_safe() which achieves the same result.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Len Brown <lenb@kernel.org>
Link: http://lkml.kernel.org/r/20170412201042.518053336@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/powerpc/kernel/smp.c | 26 +++++++++++---------------
1 file changed, 11 insertions(+), 15 deletions(-)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 46f89e6..d68ed1f 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -787,24 +787,21 @@ static struct sched_domain_topology_level powerpc_topology[] = {
{ NULL, },
};
-void __init smp_cpus_done(unsigned int max_cpus)
+static __init long smp_setup_cpu_workfn(void *data __always_unused)
{
- cpumask_var_t old_mask;
+ smp_ops->setup_cpu(boot_cpuid);
+ return 0;
+}
- /* We want the setup_cpu() here to be called from CPU 0, but our
- * init thread may have been "borrowed" by another CPU in the meantime
- * se we pin us down to CPU 0 for a short while
+void __init smp_cpus_done(unsigned int max_cpus)
+{
+ /*
+ * We want the setup_cpu() here to be called on the boot CPU, but
+ * init might run on any CPU, so make sure it's invoked on the boot
+ * CPU.
*/
- alloc_cpumask_var(&old_mask, GFP_NOWAIT);
- cpumask_copy(old_mask, ¤t->cpus_allowed);
- set_cpus_allowed_ptr(current, cpumask_of(boot_cpuid));
-
if (smp_ops && smp_ops->setup_cpu)
- smp_ops->setup_cpu(boot_cpuid);
-
- set_cpus_allowed_ptr(current, old_mask);
-
- free_cpumask_var(old_mask);
+ work_on_cpu_safe(boot_cpuid, smp_setup_cpu_workfn, NULL);
if (smp_ops && smp_ops->bringup_done)
smp_ops->bringup_done();
@@ -812,7 +809,6 @@ void __init smp_cpus_done(unsigned int max_cpus)
dump_numa_cpu_topology();
set_sched_topology(powerpc_topology);
-
}
#ifdef CONFIG_HOTPLUG_CPU
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[patch 00/13] sched/treewide: Clean up various racy task affinity issues Thomas Gleixner <tglx@linutronix.de> - 2017-04-12 22:30 +0200
[patch 12/13] cpufreq/sparc-us2e: Replace racy task affinity logic Thomas Gleixner <tglx@linutronix.de> - 2017-04-12 22:30 +0200
Re: [patch 12/13] cpufreq/sparc-us2e: Replace racy task affinity logic Viresh Kumar <viresh.kumar@linaro.org> - 2017-04-13 05:00 +0200
[patch V2 12/13] cpufreq/sparc-us2e: Replace racy task affinity logic Thomas Gleixner <tglx@linutronix.de> - 2017-04-13 10:20 +0200
[patch V3 12/13] cpufreq/sparc-us2e: Replace racy task affinity logic Thomas Gleixner <tglx@linutronix.de> - 2017-04-13 10:30 +0200
[tip:sched/core] cpufreq/sparc-us2e: Replace racy task affinity logic tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2017-04-15 16:30 +0200
Re: [patch V2 12/13] cpufreq/sparc-us2e: Replace racy task affinity logic David Miller <davem@davemloft.net> - 2017-04-13 17:00 +0200
[patch 03/13] ia64/salinfo: Replace racy task affinity logic Thomas Gleixner <tglx@linutronix.de> - 2017-04-12 22:30 +0200
[tip:sched/core] ia64/salinfo: Replace racy task affinity logic tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2017-04-15 16:30 +0200
[patch 04/13] ia64/sn/hwperf: Replace racy task affinity logic Thomas Gleixner <tglx@linutronix.de> - 2017-04-12 22:30 +0200
[patch V 2 04/13] ia64/sn/hwperf: Replace racy task affinity logic Thomas Gleixner <tglx@linutronix.de> - 2017-04-12 23:00 +0200
[tip:sched/core] ia64/sn/hwperf: Replace racy task affinity logic tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2017-04-15 16:30 +0200
[patch 11/13] cpufreq/sparc-us3: Replace racy task affinity logic Thomas Gleixner <tglx@linutronix.de> - 2017-04-12 22:30 +0200
Re: [patch 11/13] cpufreq/sparc-us3: Replace racy task affinity logic Viresh Kumar <viresh.kumar@linaro.org> - 2017-04-13 04:50 +0200
[tip:sched/core] cpufreq/sparc-us3: Replace racy task affinity logic tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2017-04-15 16:30 +0200
[patch 01/13] ia64/topology: Remove cpus_allowed manipulation Thomas Gleixner <tglx@linutronix.de> - 2017-04-12 22:30 +0200
[tip:sched/core] ia64/topology: Remove cpus_allowed manipulation tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2017-04-15 16:30 +0200
[patch 07/13] ACPI/processor: Fix error handling in __acpi_processor_start() Thomas Gleixner <tglx@linutronix.de> - 2017-04-12 22:30 +0200
[tip:sched/core] ACPI/processor: Fix error handling in __acpi_processor_start() tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2017-04-15 16:30 +0200
[patch 08/13] ACPI/processor: Replace racy task affinity logic. Thomas Gleixner <tglx@linutronix.de> - 2017-04-12 22:30 +0200
Re: [patch 08/13] ACPI/processor: Replace racy task affinity logic. Peter Zijlstra <peterz@infradead.org> - 2017-04-13 13:50 +0200
Re: [patch 08/13] ACPI/processor: Replace racy task affinity logic. Thomas Gleixner <tglx@linutronix.de> - 2017-04-13 14:10 +0200
Re: [patch 08/13] ACPI/processor: Replace racy task affinity logic. Peter Zijlstra <peterz@infradead.org> - 2017-04-13 15:00 +0200
[tip:sched/core] ACPI/processor: Replace racy task affinity logic tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2017-04-15 16:30 +0200
[patch 13/13] crypto: n2 - Replace racy task affinity logic Thomas Gleixner <tglx@linutronix.de> - 2017-04-12 22:30 +0200
Re: [patch 13/13] crypto: n2 - Replace racy task affinity logic Herbert Xu <herbert@gondor.apana.org.au> - 2017-04-13 07:40 +0200
[patch V2 13/13] crypto: n2 - Replace racy task affinity logic Thomas Gleixner <tglx@linutronix.de> - 2017-04-13 10:30 +0200
Re: [patch V2 13/13] crypto: n2 - Replace racy task affinity logic David Miller <davem@davemloft.net> - 2017-04-13 17:00 +0200
[tip:sched/core] crypto: N2 - Replace racy task affinity logic tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2017-04-15 16:40 +0200
[patch 05/13] powerpc/smp: Replace open coded task affinity logic Thomas Gleixner <tglx@linutronix.de> - 2017-04-12 22:30 +0200
Re: [patch 05/13] powerpc/smp: Replace open coded task affinity logic Michael Ellerman <mpe@ellerman.id.au> - 2017-04-13 07:50 +0200
[tip:sched/core] powerpc/smp: Replace open coded task affinity logic tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2017-04-15 16:30 +0200
[patch 06/13] sparc/sysfs: Replace racy task affinity logic Thomas Gleixner <tglx@linutronix.de> - 2017-04-12 22:30 +0200
Re: [patch 06/13] sparc/sysfs: Replace racy task affinity logic David Miller <davem@davemloft.net> - 2017-04-13 04:00 +0200
[patch V2 06/13] sparc/sysfs: Replace racy task affinity logic Thomas Gleixner <tglx@linutronix.de> - 2017-04-13 10:20 +0200
[tip:sched/core] sparc/sysfs: Replace racy task affinity logic tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2017-04-15 16:20 +0200
[patch 02/13] workqueue: Provide work_on_cpu_safe() Thomas Gleixner <tglx@linutronix.de> - 2017-04-12 22:30 +0200
Re: [patch 02/13] workqueue: Provide work_on_cpu_safe() Dou Liyang <douly.fnst@cn.fujitsu.com> - 2017-04-13 13:20 +0200
Re: [patch 02/13] workqueue: Provide work_on_cpu_safe() Thomas Gleixner <tglx@linutronix.de> - 2017-04-13 23:30 +0200
Re: [patch 02/13] workqueue: Provide work_on_cpu_safe() Tejun Heo <tj@kernel.org> - 2017-04-14 06:20 +0200
Re: [patch 02/13] workqueue: Provide work_on_cpu_safe() Peter Zijlstra <peterz@infradead.org> - 2017-04-14 11:00 +0200
Re: [patch 02/13] workqueue: Provide work_on_cpu_safe() Thomas Gleixner <tglx@linutronix.de> - 2017-04-14 12:00 +0200
Re: [patch 02/13] workqueue: Provide work_on_cpu_safe() Peter Zijlstra <peterz@infradead.org> - 2017-04-14 12:00 +0200
[tip:sched/core] workqueue: Provide work_on_cpu_safe() tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2017-04-15 16:30 +0200
Re: [patch 00/13] sched/treewide: Clean up various racy task affinity issues Peter Zijlstra <peterz@infradead.org> - 2017-04-13 11:10 +0200
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