Hello David, 

> One could argue from a defensive programming perspective that
> this bug comes from the fact that the ifb_init_one() loop
> advances state before checking for errors ('i' is advanced before
> the 'err' check due to the loop construct), and that's why the
> error recovery code had to be coded specially :-)

Now when I look at it I might be wrong and it is not a bug at all. 
It's just coded in weird way. Anyway isn't there kfree(ifbs) missing
on error path?

The patch below should clear things a bit (against plain 2.6.20-rc2-mm1).

Signed-off-by: Mariusz Kozlowski <[EMAIL PROTECTED]>

 drivers/net/ifb.c |   16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

--- linux-2.6.20-rc2-mm1-a/drivers/net/ifb.c    2006-12-24 05:00:32.000000000 
+0100
+++ linux-2.6.20-rc2-mm1-b/drivers/net/ifb.c    2007-01-02 11:35:48.000000000 
+0100
@@ -264,18 +264,22 @@ static void ifb_free_one(int index)

 static int __init ifb_init_module(void)
 {
-       int i, err = 0;
+       int i, err;
+
        ifbs = kmalloc(numifbs * sizeof(void *), GFP_KERNEL);
        if (!ifbs)
                return -ENOMEM;
-       for (i = 0; i < numifbs && !err; i++)
+       for (i = 0; i < numifbs; i++) {
                err = ifb_init_one(i);
-       if (err) {
-               i--;
-               while (--i >= 0)
-                       ifb_free_one(i);
+               if (err)
+                       goto err;
        }
+       return 0;

+err:
+       while (i--)
+               ifb_free_one(i);
+       kfree(ifbs);
        return err;
 }



-- 
Regards,

        Mariusz Kozlowski
-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to