[PATCH 3.16 314/366] drm: set FMODE_UNSIGNED_OFFSET for drm files

Ben Hutchings
2018-10-14T15:25:41Z

From: Dave Airlie <airlied@redhat.com>

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@redhat.com>
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
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
@@ -251,6 +251,7 @@ 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));