[PATCH] drm/amdkfd: Fix a __user pointer dereference in create_signal_event

[Lang Yu]

We should not dereference __user pointers directly.
https://yarchive.net/comp/linux/user_pointers.html

Fixes: 482f07775cf5
("drm/amdkfd: Simplify event ID and signal slot management")

Signed-off-by: Lang Yu <lang...@amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_events.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_events.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
index 3eea4edee355..74d3bdcfe341 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_events.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
@@ -201,7 +201,7 @@ static int create_signal_event(struct file *devkfd,
 
        p->signal_event_count++;
 
-       ev->user_signal_address = &p->signal_page->user_address[ev->event_id];
+       ev->user_signal_address = p->signal_page->user_address + ev->event_id;
        pr_debug("Signal event number %zu created with id %d, address %p\n",
                        p->signal_event_count, ev->event_id,
                        ev->user_signal_address);
-- 
2.25.1