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From: Andrew Rybchenko <arybchenko@solarflare.com>
To: Thomas Monjalon <thomas@monjalon.net>
Cc: <dev@dpdk.org>, Ferruh Yigit <ferruh.yigit@intel.com>, <stable@dpdk.org>
Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH v2] ethdev: avoid usage of uninit device info in bad port case
Date: Tue, 23 Jul 2019 16:34:30 +0300	[thread overview]
Message-ID: <ec2b6790-f8ce-70fc-3f53-6a999a51d904@solarflare.com> (raw)
In-Reply-To: <1925153.tuYcfiiuYR@xps>

On 7/23/19 4:14 PM, Thomas Monjalon wrote:
> 23/07/2019 14:11, Andrew Rybchenko:
>> rte_eth_dev_info_get() returns void and caller does know if the function
>> does its job or not. Changing of the return value to int would be
>> API/ABI breakage which requires deprecation process and cannot be
>> backported to stable branches. For now, make sure that device info is
>> initialized even in the case of invalid port ID.
>>
>> Fixes: a30268e9a2d0 ("ethdev: reset whole dev info structure before filling")
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
>> ---
>> --- a/lib/librte_ethdev/rte_ethdev.c
>> +++ b/lib/librte_ethdev/rte_ethdev.c
>> +	/*
>> +	 * Init dev_info before port_id check since caller does not have
>> +	 * return status and does not know if get is successful or not.
>> +	 */
>> +	memset(dev_info, 0, sizeof(struct rte_eth_dev_info));
> If someone was using a canary to detect failure, it will be resetted.

I've not thought about such ways to check. I would expected check
for not NULL device or driver_name. It is not defined behaviour of
the function to not touch dev_info in the case of bad port ID.

> Why is it urgent to have this workaround?

Nothing really urgent, but I still think that it is a right fix to be
applied and backported to stable branches.
I really met calls with invalid port ID and it took some time
to understand where uninitialized data come from.

> Can we wait one more release for the definitive fix with error code?

No strong opinion, but definitive fix will not be backported.

>> +
>>   	RTE_ETH_VALID_PORTID_OR_RET(port_id);
>>   	dev = &rte_eth_devices[port_id];
>>   
>> -	memset(dev_info, 0, sizeof(struct rte_eth_dev_info));
>>   	dev_info->rx_desc_lim = lim;
>>   	dev_info->tx_desc_lim = lim;
>>   	dev_info->device = dev->device;
>>


  reply	other threads:[~2019-07-23 13:34 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-23  9:13 [dpdk-stable] [PATCH] " Andrew Rybchenko
2019-07-23 10:40 ` Ferruh Yigit
2019-07-23 12:16   ` Andrew Rybchenko
2019-07-23 12:50     ` Thomas Monjalon
2019-07-23 12:11 ` [dpdk-stable] [PATCH v2] " Andrew Rybchenko
2019-07-23 13:14   ` [dpdk-stable] [dpdk-dev] " Thomas Monjalon
2019-07-23 13:34     ` Andrew Rybchenko [this message]
2019-07-23 13:39       ` Thomas Monjalon
2019-07-23 18:45         ` Thomas Monjalon

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