diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2015-07-05 19:12:33 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2015-07-07 11:54:04 +0200 |
| commit | cbb24dc761d95fe39a7a122bb1b298e9604cae15 (patch) | |
| tree | 796028ad04f906c2c60f7fe998ed6bc7dc623d14 | |
| parent | x86/irq: Plug irq vector hotplug race (diff) | |
| download | linux-cbb24dc761d95fe39a7a122bb1b298e9604cae15.tar.xz linux-cbb24dc761d95fe39a7a122bb1b298e9604cae15.zip | |
x86/irq: Use proper locking in check_irq_vectors_for_cpu_disable()
It's unsafe to examine fields in the irq descriptor w/o holding the
descriptor lock. Add proper locking.
While at it add a comment why the vector check can run lock less
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: xiao jin <jin.xiao@intel.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Link: http://lkml.kernel.org/r/20150705171102.236544164@linutronix.de
| -rw-r--r-- | arch/x86/kernel/irq.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index 88b366487b0e..85ca76e6241c 100644 --- a/arch/x86/kernel/irq.c +++ b/arch/x86/kernel/irq.c @@ -347,14 +347,22 @@ int check_irq_vectors_for_cpu_disable(void) if (!desc) continue; + /* + * Protect against concurrent action removal, + * affinity changes etc. + */ + raw_spin_lock(&desc->lock); data = irq_desc_get_irq_data(desc); cpumask_copy(&affinity_new, data->affinity); cpumask_clear_cpu(this_cpu, &affinity_new); /* Do not count inactive or per-cpu irqs. */ - if (!irq_has_action(irq) || irqd_is_per_cpu(data)) + if (!irq_has_action(irq) || irqd_is_per_cpu(data)) { + raw_spin_unlock(&desc->lock); continue; + } + raw_spin_unlock(&desc->lock); /* * A single irq may be mapped to multiple * cpu's vector_irq[] (for example IOAPIC cluster @@ -385,6 +393,9 @@ int check_irq_vectors_for_cpu_disable(void) * vector. If the vector is marked in the used vectors * bitmap or an irq is assigned to it, we don't count * it as available. + * + * As this is an inaccurate snapshot anyway, we can do + * this w/o holding vector_lock. */ for (vector = FIRST_EXTERNAL_VECTOR; vector < first_system_vector; vector++) { |