On Mon, 23 Mar 2020 at 12:13, Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote: > > On Mon, Mar 23, 2020 at 11:13:22AM +0000, Emil Velikov wrote: > > Hi Dan, > > > > On Fri, 20 Mar 2020 at 13:23, Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote: > > > > > > If the "handles" allocation or the copy_from_user() fails then we leak > > > "objs". It's supposed to be freed in panfrost_job_cleanup(). > > > > > > Fixes: c117aa4d8701 ("drm: Add a drm_gem_objects_lookup helper") > > > Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> > > > --- > > > drivers/gpu/drm/drm_gem.c | 4 ++-- > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c > > > index a9e4a610445a..f28724f2eb69 100644 > > > --- a/drivers/gpu/drm/drm_gem.c > > > +++ b/drivers/gpu/drm/drm_gem.c > > > @@ -710,6 +710,8 @@ int drm_gem_objects_lookup(struct drm_file *filp, void __user *bo_handles, > > > if (!objs) > > > return -ENOMEM; > > > > > > + *objs_out = objs; > > > + > > > handles = kvmalloc_array(count, sizeof(u32), GFP_KERNEL); > > > if (!handles) { > > > ret = -ENOMEM; > > > @@ -723,8 +725,6 @@ int drm_gem_objects_lookup(struct drm_file *filp, void __user *bo_handles, > > > } > > > > > > ret = objects_lookup(filp, handles, count, objs); > > > - *objs_out = objs; > > > - > > > out: > > > kvfree(handles); > > > return ret; > > > > It seems that this will return error to the caller, mangle the output > > pointer and effectively still leak the objs. > > The patch works. > > This is "one function frees everything" style error handling. It gets > passed back to panfrost_ioctl_submit() which calls panfrost_job_put() > which calls panfrost_job_cleanup() which frees it. > > It's a horrible way to do error handling but this was the only actual > bug I could see with the approach. > > > Better option IMHO is to: > > - move the __user/copy_from_user into the caller > > Removes a silly kvmalloc_array(1,...) in ~90+ users and drops the "out" label. > > Extra bonus, this is the only instance in drm_gem with __user - > > consistency is nice. > > - add "err" or similar label, where the objs is freed before returning an error. > > Those sound like good ideas. Also we could use kvcalloc() instead of > kvmalloc_array() with __GFP_ZERO. But it's too much for me to do... > I'm mostly focused on static analysis warnings. > Your patch addresses the issue with the smallest diffstat, so I've pushed it to drm-misc-next. Thanks Emil _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel