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| author | Alan Stern <stern@rowland.harvard.edu> | 2009-12-04 11:06:57 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-12-11 11:24:55 -0800 |
| commit | 3589972e51fac1e02d0aaa576fa47f568cb94d40 (patch) | |
| tree | 05e89c751f410a3b54583f948ff9ffc841c333ea | |
| parent | c60e0504c8e4fa14179d0687d80ef25148dd6dd4 (diff) | |
| download | linux-3589972e51fac1e02d0aaa576fa47f568cb94d40.tar.gz | |
Driver core: fix race in dev_driver_string
This patch (as1310) works around a race in dev_driver_string(). If the device is unbound while the function is running, dev->driver might become NULL after we test it and before we dereference it. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Cc: stable <stable@kernel.org> Cc: Oliver Neukum <oliver@neukum.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/base/core.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index 353b13782165..f1290cbd1350 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -56,7 +56,14 @@ static inline int device_is_not_partition(struct device *dev) */ const char *dev_driver_string(const struct device *dev) { - return dev->driver ? dev->driver->name : + struct device_driver *drv; + + /* dev->driver can change to NULL underneath us because of unbinding, + * so be careful about accessing it. dev->bus and dev->class should + * never change once they are set, so they don't need special care. + */ + drv = ACCESS_ONCE(dev->driver); + return drv ? drv->name : (dev->bus ? dev->bus->name : (dev->class ? dev->class->name : "")); } |