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| author | Thomas Gleixner <tglx@linutronix.de> | 2010-07-20 14:34:50 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2010-07-20 19:11:56 +0200 |
| commit | 96c5397b25bfa8910d4f89ec99190edafc251525 (patch) | |
| tree | 665dea3f4b30c0e82faffc44091dbc92d68dfde3 | |
| parent | 8e7dbdf187d6a6896873a32537fed62111a5910e (diff) | |
| download | lwn-96c5397b25bfa8910d4f89ec99190edafc251525.tar.gz lwn-96c5397b25bfa8910d4f89ec99190edafc251525.zip | |
cpu-hotplug: Prevent softirq wakeup on wrong CPU
When the plugged CPU sets the online flag it enables interrupts and
goes idle. When an interrupt happens and tried to wakeup a softirq
thread before the other cpu sets the active flag, then the softirq
thread is put on one of the active cpus. Prevent this by waiting for
the cpu_active bit.
Temporary workaround. Needs more thought.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| -rw-r--r-- | arch/x86/kernel/smpboot.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index b4e870cbdc60..4b2c0fe634a4 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -321,6 +321,9 @@ notrace static void __cpuinit start_secondary(void *unused) ipi_call_unlock(); per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE; + while (!cpumask_test_cpu(smp_processor_id(), cpu_active_mask)) + cpu_relax(); + /* enable local interrupts */ local_irq_enable(); |