[PATCH] AHCI: fix Null pointer dereference in achi_host_active()

From: Xiaotian Feng
Date: Tue Jul 16 2013 - 01:19:23 EST


commit b29900e6 introuded a regression, which resulted Null pointer
dereference for achi host with dummy ports. For ahci ports, when the
port is dummy port, its private_data will be NULL, as ata_dummy_port_ops
doesn't support ->port_start.

Reported-and-tested-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
Signed-off-by: Xiaotian Feng <xtfeng@xxxxxxxxx>
Cc: Alexander Gordeev <agordeev@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: linux-ide@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
drivers/ata/ahci.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 5064f3e..f1de689 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1147,10 +1147,16 @@ int ahci_host_activate(struct ata_host *host, int irq, unsigned int n_msis)

for (i = 0; i < host->n_ports; i++) {
struct ahci_port_priv *pp = host->ports[i]->private_data;
+ const char *desc;

+ if (ata_port_is_dummy(host->ports[i]))
+ desc = dev_driver_string(host->dev);
+ else
+ desc = pp->irq_desc;
+
rc = devm_request_threaded_irq(host->dev,
irq + i, ahci_hw_interrupt, ahci_thread_fn, IRQF_SHARED,
- pp->irq_desc, host->ports[i]);
+ desc, host->ports[i]);
if (rc)
goto out_free_irqs;
}
--
1.7.9.6 (Apple Git-31.1)

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