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authorThomas Gleixner <tglx@linutronix.de>2015-07-05 17:12:35 +0000
committerThomas Gleixner <tglx@linutronix.de>2015-07-07 11:54:04 +0200
commit09cf92b784fae6109450c5d64f9908066d605249 (patch)
tree5c4dcac5d736a39342f24a4d7d627a2290f54fb1
parentcbb24dc761d95fe39a7a122bb1b298e9604cae15 (diff)
downloadlinux-next-09cf92b784fae6109450c5d64f9908066d605249.tar.gz
x86/irq: Retrieve irq data after locking irq_desc
irq_data is protected by irq_desc->lock, so retrieving the irq chip from irq_data outside the lock is racy vs. an concurrent update. Move it into the lock held region. While at it add a comment why the vector walk does not require vector_lock. 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/20150705171102.331320612@linutronix.de
-rw-r--r--arch/x86/kernel/irq.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 85ca76e6241c..c7dfe1be784e 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -497,6 +497,11 @@ void fixup_irqs(void)
*/
mdelay(1);
+ /*
+ * We can walk the vector array of this cpu without holding
+ * vector_lock because the cpu is already marked !online, so
+ * nothing else will touch it.
+ */
for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
unsigned int irr;
@@ -508,9 +513,9 @@ void fixup_irqs(void)
irq = __this_cpu_read(vector_irq[vector]);
desc = irq_to_desc(irq);
+ raw_spin_lock(&desc->lock);
data = irq_desc_get_irq_data(desc);
chip = irq_data_get_irq_chip(data);
- raw_spin_lock(&desc->lock);
if (chip->irq_retrigger) {
chip->irq_retrigger(data);
__this_cpu_write(vector_irq[vector], VECTOR_RETRIGGERED);