[PATCH V2] video: fbdev: w100fb: Fix a potential double free.

Christophe JAILLET christophe.jaillet at wanadoo.fr
Wed May 6 18:19:02 UTC 2020

Some memory is vmalloc'ed in the 'w100fb_save_vidmem' function and freed in
the 'w100fb_restore_vidmem' function. (these functions are called
respectively from the 'suspend' and the 'resume' functions)

However, it is also freed in the 'remove' function.

In order to avoid a potential double free, set the corresponding pointer
to NULL once freed in the 'w100fb_restore_vidmem' function.

Fixes: aac51f09d96a ("[PATCH] w100fb: Rewrite for platform independence")
Cc: Richard Purdie <rpurdie at rpsys.net>
Cc: Antonino Daplas <adaplas at pol.net>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie at samsung.com>
Cc: <stable at vger.kernel.org> # v2.6.14+
Signed-off-by: Christophe JAILLET <christophe.jaillet at wanadoo.fr>
v2: - Add Cc: tags
    - Reword the commit message to give the names of the functions that
      allocate and free the memory. These functions are called from the
      suspend and resume function.
 drivers/video/fbdev/w100fb.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/video/fbdev/w100fb.c b/drivers/video/fbdev/w100fb.c
index 2d6e2738b792..d96ab28f8ce4 100644
--- a/drivers/video/fbdev/w100fb.c
+++ b/drivers/video/fbdev/w100fb.c
@@ -588,6 +588,7 @@ static void w100fb_restore_vidmem(struct w100fb_par *par)
 		memcpy_toio(remapped_fbuf + (W100_FB_BASE-MEM_WINDOW_BASE), par->saved_extmem, memsize);
+		par->saved_extmem = NULL;
 	if (par->saved_intmem) {
@@ -596,6 +597,7 @@ static void w100fb_restore_vidmem(struct w100fb_par *par)
 			memcpy_toio(remapped_fbuf + (W100_FB_BASE-MEM_WINDOW_BASE), par->saved_intmem, memsize);
+		par->saved_intmem = NULL;

More information about the dri-devel mailing list