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Date:   Mon, 9 Aug 2021 12:06:17 -0400
From:   Sasha Levin <sashal@kernel.org>
To:     Eric Dumazet <eric.dumazet@gmail.com>
Cc:     linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        gushengxian <gushengxian@yulong.com>,
        gushengxian <13145886936@163.com>,
        "David S . Miller" <davem@davemloft.net>, netdev@vger.kernel.org
Subject: Re: [PATCH AUTOSEL 5.13 184/189] flow_offload: action should not be
 NULL when it is referenced
Message-ID: <YRFSebqqB7HM7lsK@sashalap>
References: <20210706111409.2058071-1-sashal@kernel.org>
 <20210706111409.2058071-184-sashal@kernel.org>
 <caf751a7-ef2d-e31d-85e9-801e748b70dc@gmail.com>
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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@yulong.com>
>>
>> [ Upstream commit 9ea3e52c5bc8bb4a084938dc1e3160643438927a ]
>>
>> "action" should not be NULL when it is referenced.
>>
>> Signed-off-by: gushengxian <13145886936@163.com>
>> Signed-off-by: gushengxian <gushengxian@yulong.com>
>> Signed-off-by: David S. Miller <davem@davemloft.net>
>> Signed-off-by: Sasha Levin <sashal@kernel.org>
>> ---
>>  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