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authorNicolai Stange <nstange@suse.de>2017-09-11 10:45:40 +0300
committerBjorn Helgaas <bhelgaas@google.com>2017-09-26 02:34:54 +0300
commit9561475db680f7144d2223a409dd3d7e322aca03 (patch)
tree34aa91f19f3c51bd13402386634f00ac38031371 /drivers/pci/pci-sysfs.c
parentfe59493240169a2cc3f445ae5f2a2308fda06b63 (diff)
downloadlinux-9561475db680f7144d2223a409dd3d7e322aca03.tar.xz
PCI: Fix race condition with driver_override
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 the race condition. This is in close analogy to commit 6265539776a0 ("driver core: platform: fix race condition with driver_override") from Adrian Salido. Fixes: 782a985d7af2 ("PCI: Introduce new device binding path using pci_dev.driver_override") Signed-off-by: Nicolai Stange <nstange@suse.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: stable@vger.kernel.org # v3.16+
Diffstat (limited to 'drivers/pci/pci-sysfs.c')
-rw-r--r--drivers/pci/pci-sysfs.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 1eecfa301f7f..8e075ea2743e 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -686,7 +686,7 @@ static ssize_t driver_override_store(struct device *dev,
const char *buf, size_t count)
{
struct pci_dev *pdev = to_pci_dev(dev);
- char *driver_override, *old = pdev->driver_override, *cp;
+ char *driver_override, *old, *cp;
/* We need to keep extra room for a newline */
if (count >= (PAGE_SIZE - 1))
@@ -700,12 +700,15 @@ static ssize_t driver_override_store(struct device *dev,
if (cp)
*cp = '\0';
+ device_lock(dev);
+ old = pdev->driver_override;
if (strlen(driver_override)) {
pdev->driver_override = driver_override;
} else {
kfree(driver_override);
pdev->driver_override = NULL;
}
+ device_unlock(dev);
kfree(old);
@@ -716,8 +719,12 @@ static ssize_t driver_override_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct pci_dev *pdev = to_pci_dev(dev);
+ ssize_t len;
- return snprintf(buf, PAGE_SIZE, "%s\n", pdev->driver_override);
+ device_lock(dev);
+ len = snprintf(buf, PAGE_SIZE, "%s\n", pdev->driver_override);
+ device_unlock(dev);
+ return len;
}
static DEVICE_ATTR_RW(driver_override);