2014-07-16 21:13:03

by Rickard Strandqvist

Subject: [PATCH v4] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereference

This start as a fix for possible null pointer dereference.
But after discussion with especially Wolfram, Jingoo and Emil it was
decided to convert the code to uses Managed Device Resource instead.

Rickard Strandqvist (1):
i2c: busses: i2c-pxa.c: Fix for possible null pointer dereference

drivers/i2c/busses/i2c-pxa.c | 65 ++++++++++++++----------------------------
1 file changed, 22 insertions(+), 43 deletions(-)

--
1.7.10.4

2014-07-16 21:13:00

by Rickard Strandqvist

Subject: [PATCH v4] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereference

Fix for possible null pointer dereference, and there was a risk for
memory leak if something unexpected happens and the function returns.
It now uses the Managed Device Resource instead.

Signed-off-by: Rickard Strandqvist <[email protected]>
---
drivers/i2c/busses/i2c-pxa.c | 65 ++++++++++++++----------------------------
1 file changed, 22 insertions(+), 43 deletions(-)

diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index be671f7..0d0605c 100644
--- a/drivers/i2c/busses/i2c-pxa.c
+++ b/drivers/i2c/busses/i2c-pxa.c
@@ -1141,11 +1141,9 @@ static int i2c_pxa_probe(struct platform_device *dev)
struct resource *res = NULL;
int ret, irq;

- i2c = kzalloc(sizeof(struct pxa_i2c), GFP_KERNEL);
- if (!i2c) {
- ret = -ENOMEM;
- goto emalloc;
- }
+ i2c = devm_kzalloc(&dev->dev, sizeof(struct pxa_i2c), GFP_KERNEL);
+ if (!i2c)
+ return -ENOMEM;

/* Default adapter num to device id; i2c_pxa_probe_dt can override. */
i2c->adap.nr = dev->id;
@@ -1154,19 +1152,16 @@ static int i2c_pxa_probe(struct platform_device *dev)
if (ret > 0)
ret = i2c_pxa_probe_pdata(dev, i2c, &i2c_type);
if (ret < 0)
- goto eclk;
+ return ret;

res = platform_get_resource(dev, IORESOURCE_MEM, 0);
irq = platform_get_irq(dev, 0);
- if (res == NULL || irq < 0) {
- ret = -ENODEV;
- goto eclk;
- }
+ if (res == NULL || irq < 0)
+ return -ENODEV;

- if (!request_mem_region(res->start, resource_size(res), res->name)) {
- ret = -ENOMEM;
- goto eclk;
- }
+ if (!devm_request_mem_region(&dev->dev, res->start,
+ resource_size(res), res->name))
+ return -ENOMEM;

i2c->adap.owner = THIS_MODULE;
i2c->adap.retries = 5;
@@ -1176,17 +1171,13 @@ static int i2c_pxa_probe(struct platform_device *dev)

strlcpy(i2c->adap.name, "pxa_i2c-i2c", sizeof(i2c->adap.name));

- i2c->clk = clk_get(&dev->dev, NULL);
- if (IS_ERR(i2c->clk)) {
- ret = PTR_ERR(i2c->clk);
- goto eclk;
- }
+ i2c->clk = devm_clk_get(&dev->dev, NULL);
+ if (IS_ERR(i2c->clk))
+ return PTR_ERR(i2c->clk);

- i2c->reg_base = ioremap(res->start, resource_size(res));
- if (!i2c->reg_base) {
- ret = -EIO;
- goto eremap;
- }
+ i2c->reg_base = devm_ioremap_resource(&adev->dev, res));
+ if (IS_ERR(i2c->reg_base))
+ return -EIO;

i2c->reg_ibmr = i2c->reg_base + pxa_reg_layout[i2c_type].ibmr;
i2c->reg_idbr = i2c->reg_base + pxa_reg_layout[i2c_type].idbr;
@@ -1227,10 +1218,12 @@ static int i2c_pxa_probe(struct platform_device *dev)
i2c->adap.algo = &i2c_pxa_pio_algorithm;
} else {
i2c->adap.algo = &i2c_pxa_algorithm;
- ret = request_irq(irq, i2c_pxa_handler, IRQF_SHARED,
- dev_name(&dev->dev), i2c);
- if (ret)
- goto ereqirq;
+ ret = devm_request_irq(&dev->dev, irq, i2c_pxa_handler,
+ IRQF_SHARED, dev_name(&dev->dev), i2c);
+ if (ret) {
+ clk_disable_unprepare(i2c->clk);
+ return ret;
+ }
}

i2c_pxa_reset(i2c);
@@ -1244,7 +1237,7 @@ static int i2c_pxa_probe(struct platform_device *dev)
ret = i2c_add_numbered_adapter(&i2c->adap);
if (ret < 0) {
printk(KERN_INFO "I2C: Failed to add bus\n");
- goto eadapt;
+ return ret;
}

platform_set_drvdata(dev, i2c);
@@ -1257,20 +1250,6 @@ static int i2c_pxa_probe(struct platform_device *dev)
dev_name(&i2c->adap.dev));
#endif
return 0;
-
-eadapt:
- if (!i2c->use_pio)
- free_irq(irq, i2c);
-ereqirq:
- clk_disable_unprepare(i2c->clk);
- iounmap(i2c->reg_base);
-eremap:
- clk_put(i2c->clk);
-eclk:
- kfree(i2c);
-emalloc:
- release_mem_region(res->start, resource_size(res));
- return ret;
}

static int i2c_pxa_remove(struct platform_device *dev)
--
1.7.10.4