Commit-ID: cbb24dc761d95fe39a7a122bb1b298e9604cae15 Gitweb: http://git.kernel.org/tip/cbb24dc761d95fe39a7a122bb1b298e9604cae15 Author: Thomas Gleixner <[email protected]> AuthorDate: Sun, 5 Jul 2015 17:12:33 +0000 Committer: Thomas Gleixner <[email protected]> CommitDate: Tue, 7 Jul 2015 11:54:04 +0200
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 <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: xiao jin <[email protected]> Cc: Joerg Roedel <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Yanmin Zhang <[email protected]> Link: http://lkml.kernel.org/r/[email protected] --- arch/x86/kernel/irq.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index 88b36648..85ca76e 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++) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
