lkml.org 
[lkml]   [2017]   [Sep]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/3] PCI: fix race condition with driver_override
Date
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")
Cc: stable@vger.kernel.org # v3.16+
Signed-off-by: Nicolai Stange <nstange@suse.de>
---
drivers/pci/pci-sysfs.c | 11 +++++++++--
1 file 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);

--
2.13.5
\
 
 \ /
  Last update: 2017-09-11 09:46    [W:0.056 / U:1.108 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site