Messages in this thread | | | Date | Mon, 16 Jun 2014 08:26:10 -0500 | From | Steve Wise <> | Subject | Re: [PATCH] Fix memory leak in cm.c |
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On 6/15/2014 9:26 PM, Nick wrote: > This patch fixes memory by checking in function, > *get_skuff if it is be passing a Null skb > struct. > Cheers Nick > Signed-off-by: Nick <xerofoify@gmail.com> > --- > drivers/infiniband/hw/cxgb4/cm.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/infiniband/hw/cxgb4/cm.c b/drivers/infiniband/hw/cxgb4/cm.c > index 5e153f6..f9477e2 100644 > --- a/drivers/infiniband/hw/cxgb4/cm.c > +++ b/drivers/infiniband/hw/cxgb4/cm.c > @@ -340,7 +340,11 @@ static int status2errno(int status) > */ > static struct sk_buff *get_skb(struct sk_buff *skb, int len, gfp_t gfp) > { > - if (skb && !skb_is_nonlinear(skb) && !skb_cloned(skb)) { > + if (!skb) { > + return NULL; > + } > + > + else if (skb && !skb_is_nonlinear(skb) && !skb_cloned(skb)) { > skb_trim(skb, 0); > skb_get(skb); > skb_reset_transport_header(skb);
This patch is incorrect. If skb is null, then get_skb() will allocate a new one. The idea is to reuse skb if it can be reused (ie is linear and not cloned). Otherwise allocate a new one:
static struct sk_buff *get_skb(struct sk_buff *skb, int len, gfp_t gfp) { if (skb && !skb_is_nonlinear(skb) && !skb_cloned(skb)) { skb_trim(skb, 0); skb_get(skb); skb_reset_transport_header(skb); } else { skb = alloc_skb(len, gfp); } t4_set_arp_err_handler(skb, NULL, NULL); return skb; }
However, if skb is not null and (is not linear or is cloned), then we leak the skb. So there is a bug.
So the else clause should free skb if it not NULL before calling alloc_skb() to get a new one.
Steve.
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