diff options
| author | Hiroshi DOYU | 2012-05-11 11:03:09 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2012-05-14 08:46:01 -0700 |
| commit | 094e47e9fa79e28f0e51e37400ea6eea35a4ee1f (patch) | |
| tree | db1beb67a3d074f9c40f7ca71611f334566678e1 /drivers/base | |
| parent | 3ce9a7c0ac28561567fadedf1a99272e4970f740 (diff) | |
Driver Core: don't oops with unregistered driver in driver_find_device()
driver_find_device() can be called with an unregistered driver. Need
to check driver_private to see if it's populated or not, especially
under deferrable probe.
In the case that there are 2 drivers, one depends on the other. With
-EPROBE_DEFER, two drivers can use deferred probe to ensure that their
relative probe order doesn't matter. If dependee driver is probed
first, then the dependant's driver_find_device('dependee')
succeeds. If the dependant is probed first, then the dependant's
driver_find_device('dependee') should return NULL, and the dependant
should get -EPROBE_DEFER. driver_find_device() needs to return NULL if
it's not populated.
In [PATCHv5 2/3] ARM: tegra: Add SMMU enabler in AHB:
http://article.gmane.org/gmane.linux.ports.tegra/4658
"tegra_ahb_driver" may not be populated when it's called.
For more SMMU/AHB specific discussion, refer to the following thread:
https://lkml.org/lkml/2012/5/10/21
Signed-off-by: Hiroshi DOYU <hdoyu@nvidia.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base')
| -rw-r--r-- | drivers/base/driver.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/base/driver.c b/drivers/base/driver.c index 3ec3896c83a6..207c27ddf828 100644 --- a/drivers/base/driver.c +++ b/drivers/base/driver.c @@ -80,7 +80,7 @@ struct device *driver_find_device(struct device_driver *drv, struct klist_iter i; struct device *dev; - if (!drv) + if (!drv || !drv->p) return NULL; klist_iter_init_node(&drv->p->klist_devices, &i, |