Eric Lee / smarc-ti-linux-kernel

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Commit 6acbfb96976fc3350e30d964acb1dbbdf876d55e

Authored by Lai Jiangshan
Committed by Ingo Molnar
1 parent 4dac0b6383
Exists in ti-lsk-linux-4.1.y and in 12 other branches dlt-processor-sdk-linux-03.00.00.04, processor-sdk-linux-02.00.01, smarc-ti-linux-3.15.y, smarc-ti-lsk-linux-4.1.y, smarct3x-processor-sdk-04.01.00.06, smarct3x-processor-sdk-linux-02.00.01, smarct3x-processor-sdk-linux-03.00.00.04, smarct4x-800-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-04.01.00.06, smarct4x-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-linux-03.00.00.04, ti-linux-3.15.y

sched: Fix hotplug vs. set_cpus_allowed_ptr() 

Lai found that:

  WARNING: CPU: 1 PID: 13 at arch/x86/kernel/smp.c:124 native_smp_send_reschedule+0x2d/0x4b()
  ...
  migration_cpu_stop+0x1d/0x22

was caused by set_cpus_allowed_ptr() assuming that cpu_active_mask is
always a sub-set of cpu_online_mask.

This isn't true since 5fbd036b552f ("sched: Cleanup cpu_active madness").

So set active and online at the same time to avoid this particular
problem.

Fixes: 5fbd036b552f ("sched: Cleanup cpu_active madness")
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael wang <wangyun@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Link: http://lkml.kernel.org/r/53758B12.8060609@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Showing 2 changed files with 4 additions and 3 deletions Side-by-side Diff

... ... @@ -726,10 +726,12 @@
726 726  
727 727 void set_cpu_online(unsigned int cpu, bool online)
728 728 {
729   - if (online)
  729 + if (online) {
730 730 cpumask_set_cpu(cpu, to_cpumask(cpu_online_bits));
731   - else
  731 + cpumask_set_cpu(cpu, to_cpumask(cpu_active_bits));
  732 + } else {
732 733 cpumask_clear_cpu(cpu, to_cpumask(cpu_online_bits));
  734 + }
733 735 }
734 736  
735 737 void set_cpu_active(unsigned int cpu, bool active)
... ... @@ -5076,7 +5076,6 @@
5076 5076 unsigned long action, void *hcpu)
5077 5077 {
5078 5078 switch (action & ~CPU_TASKS_FROZEN) {
5079   - case CPU_STARTING:
5080 5079 case CPU_DOWN_FAILED:
5081 5080 set_cpu_active((long)hcpu, true);
5082 5081 return NOTIFY_OK;