[PATCH v2 05/43] fbdev/deferred-io: Test smem_start for I/O memory

Thomas Zimmermann
2024-04-10T13:06:02Z

Test smem_start before looking up pages from its value. Return
NULL if it is unset. This will result in a SIGBUS signal.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
drivers/video/fbdev/core/fb_defio.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/video/fbdev/core/fb_defio.c b/drivers/video/fbdev/core/fb_defio.c
index b38f775cd39dd..fe84218ded457 100644
--- a/drivers/video/fbdev/core/fb_defio.c
+++ b/drivers/video/fbdev/core/fb_defio.c
@@ -26,11 +26,11 @@
static struct page *fb_deferred_io_page(struct fb_info *info, unsigned long offs)
{
const void *screen_buffer = info->screen_buffer;
- struct page *page;
+ struct page *page = NULL;

if (is_vmalloc_addr(screen_buffer + offs))
page = vmalloc_to_page(screen_buffer + offs);
- else
+ else if (info->fix.smem_start)
page = pfn_to_page((info->fix.smem_start + offs) >> PAGE_SHIFT);

return page;
--
2.44.0