Patchwork [v2] AHCI: fix Null pointer dereference in achi_host_active()

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Submitter Xiaotian Feng
Date July 23, 2013, 3:54 a.m.
Message ID <1374551650-56759-1-git-send-email-xtfeng@gmail.com>
Download mbox | patch
Permalink /patch/260950/
State Not Applicable
Delegated to: David Miller
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Comments

Xiaotian Feng - July 23, 2013, 3:54 a.m.
commit b29900e6 (AHCI: Make distinct names for ports in /proc/interrupts)
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.

changes in v2: use pp to check dummy ports, update comments

Reported-and-tested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Xiaotian Feng <xtfeng@gmail.com>
Cc: Alexander Gordeev <agordeev@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: linux-ide@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
---
 drivers/ata/ahci.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)
Tejun Heo - July 23, 2013, 2:26 p.m.
On Tue, Jul 23, 2013 at 11:54:10AM +0800, Xiaotian Feng wrote:
> commit b29900e6 (AHCI: Make distinct names for ports in /proc/interrupts)
> 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.
> 
> changes in v2: use pp to check dummy ports, update comments
> 
> Reported-and-tested-by: Alex Williamson <alex.williamson@redhat.com>
> Signed-off-by: Xiaotian Feng <xtfeng@gmail.com>
> Cc: Alexander Gordeev <agordeev@redhat.com>
> Cc: Tejun Heo <tj@kernel.org>
> Cc: linux-ide@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org

Applied to libata/for-3.11-fixes.

Thanks.

Patch

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 5064f3e..db4380d 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1146,11 +1146,18 @@  int ahci_host_activate(struct ata_host *host, int irq, unsigned int n_msis)
 		return rc;
 
 	for (i = 0; i < host->n_ports; i++) {
+		const char* desc;
 		struct ahci_port_priv *pp = host->ports[i]->private_data;
 
+		/* pp is NULL for dummy ports */
+		if (pp)
+			desc = pp->irq_desc;
+		else
+			desc = dev_driver_string(host->dev);
+
 		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;
 	}