from netdev... applied 2/13/11.

-------- Original Message --------
Subject:        [PATCH] ATM, Solos PCI ADSL2+: Don't deref NULL pointer if 
net_ratelimit() and alloc_skb() interact badly.
Date:   Sun, 13 Feb 2011 21:49:32 +0100 (CET)
From:   Jesper Juhl <[email protected]>
To:     [email protected]
CC:     Chas Williams <[email protected]>, [email protected], 
[email protected], Nathan Williams <[email protected]>, David Woodhouse 
<[email protected]>, Treker Chen <[email protected]>



If alloc_skb() fails to allocate memory and returns NULL then we want to
return -ENOMEM from drivers/atm/solos-pci.c::popen() regardless of the
value of net_ratelimit(). The way the code is today, we may not return if
net_ratelimit() returns 0, then we'll proceed to pass a NULL pointer to
skb_put() which will blow up in our face.
This patch ensures that we always return -ENOMEM on alloc_skb() failure
and only let the dev_warn() be controlled by the value of net_ratelimit().

Signed-off-by: Jesper Juhl<[email protected]>
---
 solos-pci.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/atm/solos-pci.c b/drivers/atm/solos-pci.c
index 73fb1c4..25ef1a4 100644
--- a/drivers/atm/solos-pci.c
+++ b/drivers/atm/solos-pci.c
@@ -866,8 +866,9 @@ static int popen(struct atm_vcc *vcc)
        }

        skb = alloc_skb(sizeof(*header), GFP_ATOMIC);
-       if (!skb&&  net_ratelimit()) {
-               dev_warn(&card->dev->dev, "Failed to allocate sk_buff in 
popen()\n");
+       if (!skb) {
+               if (net_ratelimit())
+                       dev_warn(&card->dev->dev, "Failed to allocate sk_buff in 
popen()\n");
                return -ENOMEM;
        }
        header = (void *)skb_put(skb, sizeof(*header));


--
Jesper Juhl<[email protected]>             http://www.chaosbits.net/
Plain text mails only, please.
Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html



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