Re: [PATCH] phy: qcom-qmp-usb: Fix an NULL vs IS_ERR() bug

From: Johan Hovold <johan@kernel.org>
To: Chenyuan Yang <chenyuan0y@gmail.com>
Cc: vkoul@kernel.org, kishon@kernel.org, lumag@kernel.org,
	quic_kriskura@quicinc.com, manivannan.sadhasivam@linaro.org,
	konrad.dybcio@oss.qualcomm.com, quic_varada@quicinc.com,
	quic_kbajaj@quicinc.com, johan+linaro@kernel.org,
	linux-arm-msm@vger.kernel.org, linux-phy@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] phy: qcom-qmp-usb: Fix an NULL vs IS_ERR() bug
Date: Mon, 14 Apr 2025 08:57:10 +0200	[thread overview]
Message-ID: <Z_yxxoa12N9rNn2z@hovoldconsulting.com> (raw)
In-Reply-To: <20250413212518.2625540-1-chenyuan0y@gmail.com>

On Sun, Apr 13, 2025 at 04:25:18PM -0500, Chenyuan Yang wrote:
> In qmp_usb_iomap(), one branch returns the result of devm_ioremap(), which
> can be NULL. Since IS_ERR() does not catch a NULL pointer,
> add an explicit NULL check in qmp_usb_parse_dt_legacy() to prevent
> potential dereference issues.

Good catch, but please move the handling of this into the
qmp_usb_iomap() helper so that it returns an error pointer also if
devm_ioremap() fails.

> Signed-off-by: Chenyuan Yang <chenyuan0y@gmail.com>
> Fixes: 2a55ec4f0a04 ("phy: qcom-qmp-usb: merge driver data")

This is not the commit that introduced the issue; this should be:

Fixes: a5d6b1ac56cb ("phy: qcom-qmp-usb: fix memleak on probe deferral")

>  	qmp->pcs = qmp_usb_iomap(dev, np, 2, exclusive);
> +	if (!qmp->pcs)
> +		return -ENOMEM;
>  	if (IS_ERR(qmp->pcs))
>  		return PTR_ERR(qmp->pcs);

Johan

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