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authorHiroshi DOYU <hdoyu@nvidia.com>2012-05-11 11:03:09 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-05-14 08:46:01 -0700
commit094e47e9fa79e28f0e51e37400ea6eea35a4ee1f (patch)
treedb1beb67a3d074f9c40f7ca71611f334566678e1 /drivers/base
parent3ce9a7c0ac28561567fadedf1a99272e4970f740 (diff)
downloadlinux-094e47e9fa79e28f0e51e37400ea6eea35a4ee1f.tar.bz2
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.c2
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,