diff options
| author | Nicolai Stange <nstange@suse.de> | 2017-09-11 09:45:40 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-10-05 09:44:03 +0200 |
| commit | bb1e06d281a82c75487fb7ddf25e540b82db4306 (patch) | |
| tree | fb6b61d98904dda324ca79281c10fba8cec4af9d /drivers/pci/pci-sysfs.c | |
| parent | 46f062e05920a4d40dbe32aa4bc622df33db6fb2 (diff) | |
PCI: Fix race condition with driver_override
commit 9561475db680f7144d2223a409dd3d7e322aca03 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/pci/pci-sysfs.c')
| -rw-r--r-- | drivers/pci/pci-sysfs.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 1b0786555394..f9f4d1c18eb2 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -527,7 +527,7 @@ 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)) @@ -541,12 +541,15 @@ 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); @@ -557,8 +560,12 @@ 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); |