ARM: amba: Fix race condition with driver_override (6a7228d9) · Commits · 戴 / test

The driver_override implementation is susceptible to a race condition when different threads are reading vs storing a different driver override. Add locking to avoid this race condition. Cfr. commits ("driver core: platform: fix race condition with driver_override") and ("PCI: Fix race condition with driver_override"). Fixes: ("ARM: 8256/1: driver coamba: add device binding path 'driver_override'") Signed-off-by:

Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by:

Todd Kjos <tkjos@google.com> Cc: stable <stable@vger.kernel.org> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/amba/bus.c

+9 −2

Original line number	Diff line number	Diff line
		@@ -69,8 +69,12 @@ static ssize_t driver_override_show(struct device *_dev,
		struct device_attribute attr, char buf)
		{
		struct amba_device *dev = to_amba_device(_dev);
		ssize_t len;

		return sprintf(buf, "%s\n", dev->driver_override);
		device_lock(_dev);
		len = sprintf(buf, "%s\n", dev->driver_override);
		device_unlock(_dev);
		return len;
		}

		static ssize_t driver_override_store(struct device *_dev,
		@@ -78,7 +82,7 @@ static ssize_t driver_override_store(struct device *_dev,
		const char *buf, size_t count)
		{
		struct amba_device *dev = to_amba_device(_dev);
		char driver_override, old = dev->driver_override, *cp;
		char driver_override, old, *cp;

		/* We need to keep extra room for a newline */
		if (count >= (PAGE_SIZE - 1))
		@@ -92,12 +96,15 @@ static ssize_t driver_override_store(struct device *_dev,
		if (cp)
		*cp = '\0';

		device_lock(_dev);
		old = dev->driver_override;
		if (strlen(driver_override)) {
		dev->driver_override = driver_override;
		} else {
		kfree(driver_override);
		dev->driver_override = NULL;
		}
		device_unlock(_dev);

		kfree(old);

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