[PATCH] drm: avoid passing null pointer to memset

When cmd isn't IOC_IN | IOC_OUT a null "kdata" goes to "memset", which dereferences it.

v2: simpler version just using usize = 0 instead of allocating useless memory

Signed-off-by: Rodrigo Vivi rodrigo.vivi@gmail.com --- drivers/gpu/drm/drm_drv.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 1490e76..f72dce5 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -444,7 +444,8 @@ long drm_ioctl(struct file *filp, } if (asize > usize) memset(kdata + usize, 0, asize - usize); - } + } else + usize = 0;

if (cmd & IOC_IN) { if (copy_from_user(kdata, (void __user *)arg,