Re: [PATCH] RDMA/siw: Fix a memory leak in siw_init_cpulist()

[Dan Carpenter <dan.carpenter@oracle.com>]

On Fri, Aug 09, 2019 at 11:44:45AM +0000, Bernard Metzler wrote:
> -----"Dan Carpenter" <dan.carpenter@oracle.com> wrote: -----
> 
> >To: "Bernard Metzler" <bmt@zurich.ibm.com>
> >From: "Dan Carpenter" <dan.carpenter@oracle.com>
> >Date: 08/09/2019 12:16PM
> >Cc: "Doug Ledford" <dledford@redhat.com>, "Jason Gunthorpe"
> ><jgg@ziepe.ca>, linux-rdma@vger.kernel.org,
> >kernel-janitors@vger.kernel.org
> >Subject: [EXTERNAL] [PATCH] RDMA/siw: Fix a memory leak in
> >siw_init_cpulist()
> >
> >The error handling code doesn't free siw_cpu_info.tx_valid_cpus[0].
> >The
> >first iteration through the loop is a no-op so this is sort of an off
> >by
> >one bug.
> >
> >Fixes: bdcf26bf9b3a ("rdma/siw: network and RDMA core interface")
> >Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> >---
> > drivers/infiniband/sw/siw/siw_main.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> >diff --git a/drivers/infiniband/sw/siw/siw_main.c
> >b/drivers/infiniband/sw/siw/siw_main.c
> >index d0f140daf659..95ace3967391 100644
> >--- a/drivers/infiniband/sw/siw/siw_main.c
> >+++ b/drivers/infiniband/sw/siw/siw_main.c
> >@@ -160,9 +160,9 @@ static int siw_init_cpulist(void)
> > 
> > out_err:
> > 	siw_cpu_info.num_nodes = 0;
> >-	while (i) {
> >+	while (--i >= 0) {
> > 		kfree(siw_cpu_info.tx_valid_cpus[i]);
> >-		siw_cpu_info.tx_valid_cpus[i--] = NULL;
> >+		siw_cpu_info.tx_valid_cpus[i] = NULL;
> > 	}
> > 	kfree(siw_cpu_info.tx_valid_cpus);
> > 	siw_cpu_info.tx_valid_cpus = NULL;
> >-- 
> >2.20.1
> >
> >
> Dan, many thanks for catching this one!
> 
> I suggest you provide an even simpler fix, taking the 
> chance to remove the redundant
> "siw_cpu_info.tx_valid_cpus[i] = NULL;" line (since
> the whole structure gets kfree'd a line further
> down...).
> This shall be suffcient:
> 
> -	while (i) {
> +	while (--i >= 0)
>  		kfree(siw_cpu_info.tx_valid_cpus[i]);
> -		siw_cpu_info.tx_valid_cpus[i--] = NULL;

Yeah that's a good point.  I'll resend.

regards,
dan carpenter