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64 lines
1.9 KiB
Diff
64 lines
1.9 KiB
Diff
From 6265539776a0810b7ce6398c27866ddb9c6bd154 Mon Sep 17 00:00:00 2001
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From: Adrian Salido <salidoa@google.com>
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Date: Tue, 25 Apr 2017 16:55:26 -0700
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Subject: driver core: platform: fix race condition with driver_override
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The driver_override implementation is susceptible to race condition when
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different threads are reading vs storing a different driver override.
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Add locking to avoid race condition.
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Fixes: 3d713e0e382e ("driver core: platform: add device binding path 'driver_override'")
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Cc: stable@vger.kernel.org
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Signed-off-by: Adrian Salido <salidoa@google.com>
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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---
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drivers/base/platform.c | 11 +++++++++--
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1 file changed, 9 insertions(+), 2 deletions(-)
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diff --git a/drivers/base/platform.c b/drivers/base/platform.c
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index a102152..97332d0 100644
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--- a/drivers/base/platform.c
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+++ b/drivers/base/platform.c
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@@ -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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--
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cgit v1.1
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