[PATCH 4.4 07/24] drm: set FMODE_UNSIGNED_OFFSET for drm files

From: Greg Kroah-Hartman
Date: Tue Jun 12 2018 - 13:00:09 EST

4.4-stable review patch. If anyone has any objections, please let me know.


From: Dave Airlie <airlied@xxxxxxxxxx>

commit 76ef6b28ea4f81c3d511866a9b31392caa833126 upstream.

Since we have the ttm and gem vma managers using a subset
of the file address space for objects, and these start at
0x100000000 they will overflow the new mmap checks.

I've checked all the mmap routines I could see for any
bad behaviour but overall most people use GEM/TTM VMA
managers even the legacy drivers have a hashtable.

Reported-and-Tested-by: Arthur Marsh (amarsh04 on #radeon)
Fixes: be83bbf8068 (mmap: introduce sane default mmap limits)
Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/gpu/drm/drm_fops.c | 1 +
1 file changed, 1 insertion(+)

--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -209,6 +209,7 @@ static int drm_open_helper(struct file *
return -ENOMEM;

filp->private_data = priv;
+ filp->f_mode |= FMODE_UNSIGNED_OFFSET;
priv->filp = filp;
priv->uid = current_euid();
priv->pid = get_pid(task_pid(current));