[tip:irq/core] genirq: Prevent crash in irq_move_irq()

From: tip-bot for Jiang Liu
Date: Sat Jun 20 2015 - 13:20:20 EST

Commit-ID: 77ed42f18edd486e9994ccd1f174076309a6343f
Gitweb: http://git.kernel.org/tip/77ed42f18edd486e9994ccd1f174076309a6343f
Author: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
AuthorDate: Mon, 1 Jun 2015 16:05:11 +0800
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Fri, 12 Jun 2015 16:54:21 +0200

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

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.

Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1433145945-789-3-git-send-email-jiang.liu@xxxxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
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 ca3f4aa..dd203e2 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)))
@@ -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)))

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