Messages in this thread Patch in this message | | | Date | Thu, 31 Mar 2022 11:00:46 +0200 | From | Greg KH <> | Subject | Re: [PATCH v3] misc/mei: Add NULL check to component match callback functions |
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On Thu, Mar 31, 2022 at 08:49:18AM +0000, Won Chung wrote: > Component match callback functions need to check if expected data is > passed to them. Without this check, it can cause a NULL pointer > dereference when another driver registers a component before i915 > drivers have their component master fully bind.
How can that happen in a real system? Or does this just happen for when you are doing development and testing?
> > Fixes: 1e8d19d9b0dfc ("mei: hdcp: bind only with i915 on the same PCH") > Fixes: c2004ce99ed73 ("mei: pxp: export pavp client to me client bus") > Suggested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> > Suggested-by: Mika Westerberg <mika.westerberg@linux.intel.com> > Signed-off-by: Won Chung <wonchung@google.com> > Cc: stable@vger.kernel.org
Why does this need to go to stable? How can this be triggered in older kernels?
> --- > Changes from v2: > - Correctly add "Suggested-by" tag > - Add "Cc: stable@vger.kernel.org" > > Changes from v1: > - Add "Fixes" tag > - Send to stable@vger.kernel.org > > drivers/misc/mei/hdcp/mei_hdcp.c | 2 +- > drivers/misc/mei/pxp/mei_pxp.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/misc/mei/hdcp/mei_hdcp.c b/drivers/misc/mei/hdcp/mei_hdcp.c > index ec2a4fce8581..843dbc2b21b1 100644 > --- a/drivers/misc/mei/hdcp/mei_hdcp.c > +++ b/drivers/misc/mei/hdcp/mei_hdcp.c > @@ -784,7 +784,7 @@ static int mei_hdcp_component_match(struct device *dev, int subcomponent, > { > struct device *base = data; > > - if (strcmp(dev->driver->name, "i915") || > + if (!base || !dev->driver || strcmp(dev->driver->name, "i915") ||
How can base be NULL?
> subcomponent != I915_COMPONENT_HDCP) > return 0; > > diff --git a/drivers/misc/mei/pxp/mei_pxp.c b/drivers/misc/mei/pxp/mei_pxp.c > index f7380d387bab..e32a81da8af6 100644 > --- a/drivers/misc/mei/pxp/mei_pxp.c > +++ b/drivers/misc/mei/pxp/mei_pxp.c > @@ -131,7 +131,7 @@ static int mei_pxp_component_match(struct device *dev, int subcomponent, > { > struct device *base = data; > > - if (strcmp(dev->driver->name, "i915") || > + if (!base || !dev->driver || strcmp(dev->driver->name, "i915") ||
Same here, shouldn't this be caught by the driver core or bus and match should not be called?
Why not fix this in the component/driver core instead?
thanks,
greg k-h
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