ps3fb: prevent use after free of fb_info

In ps3fb_shutdown, freeing the framebuffer will cause fb_info (in
dev->core.driver_data) to be free()ed, which we potentially access
from the ps3fbd kthread.

This change frees the framebuffer after stopping the ps3fbd kthread.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 6 deletions

diff --git a/drivers/video/ps3fb.c b/drivers/video/ps3fb.c
index b3128903d673..ae07e02943d8 100644
--- a/drivers/video/ps3fb.c
+++ b/drivers/video/ps3fb.c
@@ -1234,12 +1234,6 @@ static int ps3fb_shutdown(struct ps3_system_bus_device *dev)
         ps3fb_flip_ctl(0, &ps3fb);      /* flip off */
         ps3fb.dinfo->irq.mask = 0;
 
-        if (info) {
-                unregister_framebuffer(info);
-                fb_dealloc_cmap(&info->cmap);
-                framebuffer_release(info);
-        }
-
         ps3av_register_flip_ctl(NULL, NULL);
         if (ps3fb.task) {
                 struct task_struct *task = ps3fb.task;
@@ -1250,6 +1244,12 @@ static int ps3fb_shutdown(struct ps3_system_bus_device *dev)
                 free_irq(ps3fb.irq_no, &dev->core);
                 ps3_irq_plug_destroy(ps3fb.irq_no);
         }
+        if (info) {
+                unregister_framebuffer(info);
+                fb_dealloc_cmap(&info->cmap);
+                framebuffer_release(info);
+                info = dev->core.driver_data = NULL;
+        }
         iounmap((u8 __iomem *)ps3fb.dinfo);
 
         status = lv1_gpu_context_free(ps3fb.context_handle);