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From: Ferruh Yigit <ferruh.yigit@intel.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: dev@dpdk.org, stable@dpdk.org
Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH] kni: fix build with gcc 8.1
Date: Wed, 20 Jun 2018 18:04:42 +0100	[thread overview]
Message-ID: <6bcc0a2c-9dbb-eefb-412c-10fea466e213@intel.com> (raw)
In-Reply-To: <90559d85-5fc2-8f77-3b2f-676c9d0b664a@intel.com>

On 6/20/2018 5:39 PM, Ferruh Yigit wrote:
> On 6/20/2018 12:35 AM, Stephen Hemminger wrote:
>> On Tue, 19 Jun 2018 13:08:55 +0100
>> Ferruh Yigit <ferruh.yigit@intel.com> wrote:
>>
>>> Error observed when CONFIG_RTE_KNI_KMOD_ETHTOOL config option is
>>> enabled.
>>>
>>> build error:
>>> In function ‘strncpy’,
>>>     inlined from ‘igb_get_drvinfo’ at
>>>     .../dpdk/build/build/kernel/linux/kni/igb_ethtool.c:814:2:
>>>     .../include/linux/string.h:246:9: error: ‘__builtin_strncpy’ output
>>>     may be truncated copying 31 bytes from a string of length 42
>>>     [-Werror=stringop-truncation]
>>>       return __builtin_strncpy(p, q, size);
>>>                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>
>>> Fixed by reducing the adapter->fw_version size and adjusting strncpy
>>> limit size.
>>>
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
>>> ---
>>>  kernel/linux/kni/ethtool/igb/igb.h         | 2 +-
>>>  kernel/linux/kni/ethtool/igb/igb_ethtool.c | 2 +-
>>>  2 files changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/kernel/linux/kni/ethtool/igb/igb.h b/kernel/linux/kni/ethtool/igb/igb.h
>>> index 8aa2a3088..5e798ae83 100644
>>> --- a/kernel/linux/kni/ethtool/igb/igb.h
>>> +++ b/kernel/linux/kni/ethtool/igb/igb.h
>>> @@ -592,7 +592,7 @@ struct igb_adapter {
>>>  	int int_mode;
>>>  	u32 rss_queues;
>>>  	u32 vmdq_pools;
>>> -	char fw_version[43];
>>> +	char fw_version[32];
>>
>> Use ETHTOOL_FWVERS_LEN?
> 
> Yes, that is what drvinfo->fw_version uses, and it seems it has been around
> enough to not cause any build issue, will use that one.

Ah so much fun, it has been updated to 43 by me in the past, to prevent another
warning [1] which another part of code has potential to write larger string to
fw_version.

Reducing value back to 32 may bring back that old warning ...

[1]
Fixes: c3698192940c ("kni: fix build with gcc 7.1")

> 
>>
>>>  	u32 wvbr;
>>>  	struct igb_mac_addr *mac_table;
>>>  #ifdef CONFIG_IGB_VMDQ_NETDEV
>>> diff --git a/kernel/linux/kni/ethtool/igb/igb_ethtool.c b/kernel/linux/kni/ethtool/igb/igb_ethtool.c
>>> index 064528bcf..0b8b25ff1 100644
>>> --- a/kernel/linux/kni/ethtool/igb/igb_ethtool.c
>>> +++ b/kernel/linux/kni/ethtool/igb/igb_ethtool.c
>>> @@ -812,7 +812,7 @@ static void igb_get_drvinfo(struct net_device *netdev,
>>>  	strncpy(drvinfo->version, igb_driver_version, sizeof(drvinfo->version) - 1);
>>>  
>>>  	strncpy(drvinfo->fw_version, adapter->fw_version,
>>> -		sizeof(drvinfo->fw_version) - 1);
>>> +		sizeof(drvinfo->fw_version));
>>
>> Why not:
>> 	strlcpy(drvinfo->fw_version, adapter->fw_version,
>> 		sizeof(drvinfo->fw_version));
> 
> Just to be cautious about changing API, to not have any problem with older
> version of kernels.
> But it seems strlcpy supported long enough to not cause an issue, I will use it.
> 

  reply	other threads:[~2018-06-20 17:04 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-19 12:08 [dpdk-stable] " Ferruh Yigit
2018-06-19 23:35 ` [dpdk-stable] [dpdk-dev] " Stephen Hemminger
2018-06-20 16:39   ` Ferruh Yigit
2018-06-20 17:04     ` Ferruh Yigit [this message]
2018-06-20  9:01 ` [dpdk-stable] " De Lara Guarch, Pablo
2018-06-20 16:40   ` Ferruh Yigit
2018-06-26  9:02 ` [dpdk-stable] [PATCH v2] " Ferruh Yigit
2018-06-26  9:54   ` Thomas Monjalon
2018-06-26 11:38   ` [dpdk-stable] [PATCH v3] " Ferruh Yigit
2018-06-26 13:43     ` De Lara Guarch, Pablo
2018-06-27 13:15       ` Thomas Monjalon

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