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driver core: platform: fix race condition with driver_override
The driver_override implementation is susceptible to race condition when
different threads are reading vs storing a different driver override.
Add locking to avoid race condition.
Fixes: 3d713e0e38
("driver core: platform: add device binding path 'driver_override'")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Salido <salidoa@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
08332893e3
commit
6265539776
@ -866,7 +866,7 @@ static ssize_t driver_override_store(struct device *dev,
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const char *buf, size_t count)
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{
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struct platform_device *pdev = to_platform_device(dev);
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char *driver_override, *old = pdev->driver_override, *cp;
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char *driver_override, *old, *cp;
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if (count > PATH_MAX)
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return -EINVAL;
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@ -879,12 +879,15 @@ static ssize_t driver_override_store(struct device *dev,
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if (cp)
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*cp = '\0';
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device_lock(dev);
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old = pdev->driver_override;
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if (strlen(driver_override)) {
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pdev->driver_override = driver_override;
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} else {
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kfree(driver_override);
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pdev->driver_override = NULL;
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}
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device_unlock(dev);
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kfree(old);
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@ -895,8 +898,12 @@ static ssize_t driver_override_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct platform_device *pdev = to_platform_device(dev);
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ssize_t len;
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return sprintf(buf, "%s\n", pdev->driver_override);
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device_lock(dev);
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len = sprintf(buf, "%s\n", pdev->driver_override);
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device_unlock(dev);
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return len;
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}
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static DEVICE_ATTR_RW(driver_override);
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