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Subject: Re: [PATCH net-next] net/fsl: xgmac_mdio: fix return value check in
 xgmac_mdio_probe()
To:     Tobias Waldekranz <tobias@waldekranz.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, Andrew Lunn <andrew@lunn.ch>,
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CC:     <netdev@vger.kernel.org>, <kernel-janitors@vger.kernel.org>,
        Hulk Robot <hulkci@huawei.com>
References: <20220129012702.3220704-1-weiyongjun1@huawei.com>
 <87czkabjgo.fsf@waldekranz.com>
From:   "weiyongjun (A)" <weiyongjun1@huawei.com>
Message-ID: <2855194d-9680-c78f-ad87-a2b789cc0363@huawei.com>
Date:   Sun, 30 Jan 2022 08:58:55 +0800
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> On Sat, Jan 29, 2022 at 01:27, Wei Yongjun <weiyongjun1@huawei.com> wrote:
>> In case of error, the function devm_ioremap() returns NULL pointer
>> not ERR_PTR(). The IS_ERR() test in the return value check should
>> be replaced with NULL test.
>>
>> Fixes: 1d14eb15dc2c ("net/fsl: xgmac_mdio: Use managed device resources")
>> Reported-by: Hulk Robot <hulkci@huawei.com>
>> Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
> Reviewed-by: Tobias Waldekranz <tobias@waldekranz.com>
>
> Sorry about that. I started out by using devm_ioremap_resource, which
> uses the in-band error signaling, and forgot to match the guard when I
> changed it.
>
> I see that this was reported by your CI, do you mind me asking what it
> is running in the back-end? At least my version of sparse does not seem
> to catch this.


It was reported by coccinelle with follow script:


@@
expression ret, E;
@@
ret = \(devm_ioport_map\|
devm_ioremap\|
devm_ioremap_wc\|
devm_irq_alloc_generic_chip\|
devm_kasprintf\|
devm_kcalloc\|
devm_kmalloc\|
devm_kmalloc_array\|
devm_kmemdup\|
devm_kstrdup\|
devm_kzalloc\|
\)(...);
... when != ret = E
(
- IS_ERR(ret)
+ !ret
|
- !IS_ERR(ret)
+ ret
|
- PTR_ERR(ret)
+ -ENOMEM
)



It seems smatch also can report this.


Regards,

Wei Yongjun