Commit-ID: 09cf92b784fae6109450c5d64f9908066d605249 Gitweb: http://git.kernel.org/tip/09cf92b784fae6109450c5d64f9908066d605249 Author: Thomas Gleixner <[email protected]> AuthorDate: Sun, 5 Jul 2015 17:12:35 +0000 Committer: Thomas Gleixner <[email protected]> CommitDate: Tue, 7 Jul 2015 11:54:04 +0200
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 <[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 | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index 85ca76e..c7dfe1b 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); -- 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/
