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Subject[PATCH 3/10] video: use safer test on the result of find_first_zero_bit
Date
From: Julia Lawall <Julia.Lawall@lip6.fr>

Find_first_zero_bit considers BITS_PER_LONG bits at a time, and thus may
return a larger number than the maximum position argument if that position
is not a multiple of BITS_PER_LONG.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression e1,e2,e3;
statement S1,S2;
@@

e1 = find_first_zero_bit(e2,e3)
...
if (e1
- ==
+ >=
e3)
S1 else S2
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---
drivers/video/fbdev/sh_mobile_meram.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff -u -p a/drivers/video/fbdev/sh_mobile_meram.c b/drivers/video/fbdev/sh_mobile_meram.c
--- a/drivers/video/fbdev/sh_mobile_meram.c
+++ b/drivers/video/fbdev/sh_mobile_meram.c
@@ -222,7 +222,7 @@ static int meram_plane_alloc(struct sh_m
unsigned long idx;

idx = find_first_zero_bit(&priv->used_icb, 28);
- if (idx == 28)
+ if (idx >= 28)
return -ENOMEM;
plane->cache = &priv->icbs[idx];



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