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>

diff --git a/drivers/video/ps3fb.c b/drivers/video/ps3fb.c
index b3128903d67328fdcb5747de418e59b177fe2dc0..ae07e02943d86946aba598c610dcb3927acd2a5f 100644 (file)
--- 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);