On Sat, 2008-12-20 at 08:35 +1000, Dave Airlie wrote: > On Sat, Dec 20, 2008 at 3:10 AM, Julia Lawall <julia@xxxxxxx> wrote: > > From: Julia Lawall <julia@xxxxxxx> > > > > If the NULL test is necessary, then the dereference should be moved below > > the NULL test. > > > > The semantic patch that makes this change is as follows: > > (http://www.emn.fr/x-info/coccinelle/). The result has been modified to > > move the initialization of driver down closer to where it is used. > > > > // <smpl> > > @@ > > type T; > > expression E; > > identifier i,fld; > > statement S; > > @@ > > > > - T i = E->fld; > > + T i; > > ... when != E > > when != i > > if (E == NULL) S > > + i = E->fld; > > // </smpl> > > > > Signed-off-by: Julia Lawall <julia@xxxxxxx> > > > > --- > > drivers/gpu/drm/drm_drv.c | 7 ++++--- > > 1 file changed, 4 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c > > index 0b9f316..4bdfc98 100644 > > --- a/drivers/gpu/drm/drm_drv.c > > +++ b/drivers/gpu/drm/drm_drv.c > > @@ -297,7 +297,7 @@ EXPORT_SYMBOL(drm_init); > > */ > > static void drm_cleanup(struct drm_device * dev) > > { > > - struct drm_driver *driver = dev->driver; > > + struct drm_driver *driver; > > > > DRM_DEBUG("\n"); > > > > @@ -324,8 +324,9 @@ static void drm_cleanup(struct drm_device * dev) > > dev->agp = NULL; > > } > > > > - if (dev->driver->unload) > > - dev->driver->unload(dev); > > + driver = dev->driver; > > + if (driver->unload) > > + driver->unload(dev); > > Huh? > > The original test is to check it dev->driver->unload exists, not it > dev->driver exists. > > I think your test parameters are wrong. No, it was valid, but I think the better patch is: From 1e0a24cfe75a328db5a50dbcdaaf0eb461638b6b Mon Sep 17 00:00:00 2001 From: Eric Anholt <eric@xxxxxxxxxx> Date: Fri, 19 Dec 2008 15:07:11 -0800 Subject: [PATCH] drm: Avoid use-before-null-test on dev in drm_cleanup(). Signed-off-by: Eric Anholt <eric@xxxxxxxxxx> --- drivers/gpu/drm/drm_drv.c | 4 +--- 1 files changed, 1 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 373e3de..febb517 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -294,8 +294,6 @@ EXPORT_SYMBOL(drm_init); */ static void drm_cleanup(struct drm_device * dev) { - struct drm_driver *driver = dev->driver; - DRM_DEBUG("\n"); if (!dev) { @@ -330,7 +328,7 @@ static void drm_cleanup(struct drm_device * dev) if (drm_core_check_feature(dev, DRIVER_MODESET)) drm_put_minor(&dev->control); - if (driver->driver_features & DRIVER_GEM) + if (dev->driver->driver_features & DRIVER_GEM) drm_gem_destroy(dev); drm_put_minor(&dev->primary); -- 1.5.6.5 -- Eric Anholt eric@xxxxxxxxxx eric.anholt@xxxxxxxxx
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