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authorThomas Gleixner <tglx@linutronix.de>2015-07-05 17:12:33 +0000
committerThomas Gleixner <tglx@linutronix.de>2015-07-07 11:54:04 +0200
commitcbb24dc761d95fe39a7a122bb1b298e9604cae15 (patch)
tree796028ad04f906c2c60f7fe998ed6bc7dc623d14
parent5a3f75e3f02836518ce49536e9c460ca8e1fa290 (diff)
downloadlinux-next-cbb24dc761d95fe39a7a122bb1b298e9604cae15.tar.gz
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.c13
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++) {