From f6b1464f647424bbeb609ec832428e4079940701 Mon Sep 17 00:00:00 2001 From: Jiang Liu Date: Mon, 1 Jun 2015 16:05:11 +0800 Subject: [PATCH] genirq: Prevent crash in irq_move_irq() The functions irq_move_irq() and irq_move_masked_irq() expect that the caller passes the top-level irq_data to them when hierarchical irqdomains are enabled. But that's not true when called from apic_ack_edge(), which results in a null pointer dereference by idata->chip->irq_mask(idata). Instead of fixing callers to passing top-level irq_data, we rather change irq_move_irq()/irq_move_masked_irq() to accept any irq_data. Fixes: 52f518a3a7c 'x86/MSI: Use hierarchical irqdomains to manage MSI interrupts' Reported-by: Huang Ying Signed-off-by: Jiang Liu Cc: Konrad Rzeszutek Wilk Cc: Tony Luck Cc: Bjorn Helgaas Cc: Benjamin Herrenschmidt Cc: Randy Dunlap Cc: Yinghai Lu Cc: Borislav Petkov Link: http://lkml.kernel.org/r/1433145945-789-3-git-send-email-jiang.liu@linux.intel.com Signed-off-by: Thomas Gleixner --- kernel/irq/migration.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/kernel/irq/migration.c b/kernel/irq/migration.c index ca3f4aaff707..dd203e276b07 100644 --- a/kernel/irq/migration.c +++ b/kernel/irq/migration.c @@ -7,7 +7,7 @@ void irq_move_masked_irq(struct irq_data *idata) { struct irq_desc *desc = irq_data_to_desc(idata); - struct irq_chip *chip = idata->chip; + struct irq_chip *chip = desc->irq_data.chip; if (likely(!irqd_is_setaffinity_pending(&desc->irq_data))) return; @@ -52,6 +52,13 @@ void irq_move_irq(struct irq_data *idata) { bool masked; + /* + * Get top level irq_data when CONFIG_IRQ_DOMAIN_HIERARCHY is enabled, + * and it should be optimized away when CONFIG_IRQ_DOMAIN_HIERARCHY is + * disabled. So we avoid an "#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY" here. + */ + idata = irq_desc_get_irq_data(irq_data_to_desc(idata)); + if (likely(!irqd_is_setaffinity_pending(idata))) return;