Patchwork AHCI: fix Null pointer dereference in achi_host_active()

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Submitter Xiaotian Feng
Date July 16, 2013, 5:18 a.m.
Message ID <1373951920-31699-1-git-send-email-xtfeng@gmail.com>
Download mbox | patch
Permalink /patch/259346/
State Not Applicable
Delegated to: David Miller
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Comments

Xiaotian Feng - July 16, 2013, 5:18 a.m.
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@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 |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
Sergei Shtylyov - July 16, 2013, 11:48 a.m.
Hello.

On 16-07-2013 9:18, Xiaotian Feng wrote:

> commit b29900e6 introuded a regression, which resulted Null pointer

    Please also specify that commit's summary in parens.

> 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@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

MBR, Sergei


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Patch

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;
 	}