Re: [bug report] RDMA/iw_cxgb4: Handle return value of c4iw_ofld_send() in abort_arp_failure()

[Dan Carpenter <dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>]

Any update on this?  It really looks buggy to me.

regards,
dan carpenter

On Thu, Feb 23, 2017 at 06:58:09PM +0300, Dan Carpenter wrote:
> Hello Hariprasad S,
> 
> The patch 761e19a504af: "RDMA/iw_cxgb4: Handle return value of
> c4iw_ofld_send() in abort_arp_failure()" from May 6, 2016, leads to
> the following static checker warning:
> 
> 	drivers/infiniband/hw/cxgb4/cm.c:575 abort_arp_failure()
> 	warn: passing freed memory 'skb'
> 
> drivers/infiniband/hw/cxgb4/cm.c
>    559  /*
>    560   * Handle an ARP failure for a CPL_ABORT_REQ.  Change it into a no RST variant
>    561   * and send it along.
>    562   */
>    563  static void abort_arp_failure(void *handle, struct sk_buff *skb)
>    564  {
>    565          int ret;
>    566          struct c4iw_ep *ep = handle;
>    567          struct c4iw_rdev *rdev = &ep->com.dev->rdev;
>    568          struct cpl_abort_req *req = cplhdr(skb);
>    569  
>    570          PDBG("%s rdev %p\n", __func__, rdev);
>    571          req->cmd = CPL_ABORT_NO_RST;
>    572          ret = c4iw_ofld_send(rdev, skb);
>    573          if (ret) {
> 
> If c4iw_ofld_send() fails then it frees skb.
> 
>    574                  __state_set(&ep->com, DEAD);
>    575                  queue_arp_failure_cpl(ep, skb, FAKE_CPL_PUT_EP_SAFE);
>                                                   ^^^
> Used after free here.  These are ref counted data so it might actually
> be that I have misread it and miscounted the references so perhaps it's
> OK, but it looks might suspect at a glance.
> 
>    576          }
>    577  }
> 
> regards,
> dan carpenter
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