Re: [PATCH AUTOSEL 5.13 184/189] flow_offload: action should not be NULL when it is referenced

[Sasha Levin]

On Fri, Aug 06, 2021 at 11:30:04AM +0200, Eric Dumazet wrote:
> On 7/6/21 1:14 PM, Sasha Levin wrote:
> > From: gushengxian <gushengxian@xxxxxxxxxx>
> >
> > [ Upstream commit 9ea3e52c5bc8bb4a084938dc1e3160643438927a ]
> >
> > "action" should not be NULL when it is referenced.
> >
> > Signed-off-by: gushengxian <13145886936@xxxxxxx>
> > Signed-off-by: gushengxian <gushengxian@xxxxxxxxxx>
> > Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> > ---
> >  include/net/flow_offload.h | 12 +++++++-----
> >  1 file changed, 7 insertions(+), 5 deletions(-)
> >
> > diff --git a/include/net/flow_offload.h b/include/net/flow_offload.h
> > index dc5c1e69cd9f..69c9eabf8325 100644
> > --- a/include/net/flow_offload.h
> > +++ b/include/net/flow_offload.h
> > @@ -319,12 +319,14 @@ flow_action_mixed_hw_stats_check(const struct flow_action *action,
> >  	if (flow_offload_has_one_action(action))
> >  		return true;
> >
> > -	flow_action_for_each(i, action_entry, action) {
> > -		if (i && action_entry->hw_stats != last_hw_stats) {
> > -			NL_SET_ERR_MSG_MOD(extack, "Mixing HW stats types for actions is not supported");
> > -			return false;
> > +	if (action) {
> > +		flow_action_for_each(i, action_entry, action) {
> > +			if (i && action_entry->hw_stats != last_hw_stats) {
> > +				NL_SET_ERR_MSG_MOD(extack, "Mixing HW stats types for actions is not supported");
> > +				return false;
> > +			}
> > +			last_hw_stats = action_entry->hw_stats;
> >  		}
> > -		last_hw_stats = action_entry->hw_stats;
> >  	}
> >  	return true;
> >  }
>
> This patch makes no sense really.
>
> If action is NULL, a crash would happen earlier anyway in
>
> if (flow_offload_has_one_action(action))
>    return true;
>
> Also, I wonder why it has been backported to stable version,
> there was no Fixes: tag in the submission.

That's the AUTOSEL logic: it will attempt to find fixes in commits that
don't have a fixes: tag. Those get longer review times and aren't
backported as quickly as commits with a stable tag or a fixes tag.

--
Thanks,
Sasha