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| author | Nicolai Stange <nstange@suse.de> | 2017-09-11 09:45:40 +0200 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2017-09-26 01:34:54 +0200 |
| commit | 9561475db680f7144d2223a409dd3d7e322aca03 (patch) | |
| tree | 34aa91f19f3c51bd13402386634f00ac38031371 /drivers | |
| parent | PCI: Add dummy pci_acs_enabled() for CONFIG_PCI=n build (diff) | |
| download | linux-9561475db680f7144d2223a409dd3d7e322aca03.tar.xz linux-9561475db680f7144d2223a409dd3d7e322aca03.zip | |
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')
| -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 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); |