[dpdk-stable] [dpdk-dev] [PATCH] net/i40e: fix unexpected mbuf free in vPMD

[Richardson, Bruce]

> -----Original Message-----
> From: Roger B. Melton [mailto:rmelton at cisco.com]
> Sent: Thursday, October 12, 2017 12:15 PM
> To: Richardson, Bruce <bruce.richardson at intel.com>
> Cc: Zhang, Qi Z <qi.z.zhang at intel.com>; Ananyev, Konstantin
> <konstantin.ananyev at intel.com>; Wu, Jingjing <jingjing.wu at intel.com>;
> Xing, Beilei <beilei.xing at intel.com>; dev at dpdk.org; stable at dpdk.org
> Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH] net/i40e: fix unexpected
> mbuf free in vPMD
> 
> On 10/10/17 7:47 AM, Roger B. Melton wrote:
> > On 10/10/17 7:39 AM, Bruce Richardson wrote:
> >> On Tue, Oct 10, 2017 at 07:05:33AM -0400, Roger B. Melton wrote:
> >>> Hi Bruce,
> >>>
> >>> I can.  It will take a day or 2 to get the results.
> >>>
> >>> Regards,
> >>> Roger
> >>>
> >> Thanks. Keep us posted. We want to ensure we have the best fix
> >> possible for the issue in this release.
> >
> > Thanks for finding a better solution ;-).  I'll let you know the
> > results when I have them, just wanted you to know it may take a couple
> > of days to turn around.
> >
> > -Roger
> 
> Confirmed that this patch does address the issue.  Thanks again Bruce/Qi
> for finding a better alternative.
> 
> Regards, Roger
> >
Great.

Acked-by: Bruce Richardson <bruce.richardson at intel.com>

See also comment below.

> >>
> >> /Bruce
> >>
> >>> On 10/10/17 4:48 AM, Bruce Richardson wrote:
> >>>> +Roger Melton
> >>>>
> >>>> On Tue, Oct 10, 2017 at 09:22:05AM -0400, Qi Zhang wrote:
> >>>>> vPMD tx does not set sw_ring's mbuf to NULL after free it.
> >>>>> So to prevent same mbuf be free again, we need more carefully
> >>>>> check in i40e_tx_queue_release_mbufs.
> >>>>>
Maybe this commit message could be reworded to be a bit more detailed.

"vPMD tx does not set sw_ring's mbuf to NULL after free.
Therefore, in cases where the vector transmit function is in
use, we must use the appropriate index and threshold values
for the queue to only free the unreleased mbufs"