From: Johan Hovold <johan@kernel.org>
To: Loic Poulain <loic.poulain@oss.qualcomm.com>
Cc: vkoul@kernel.org, kishon@kernel.org,
linux-arm-msm@vger.kernel.org, linux-phy@lists.infradead.org,
dmitry.baryshkov@oss.qualcomm.com, neil.armstrong@linaro.org,
konrad.dybcio@oss.qualcomm.com,
Abel Vesa <abel.vesa@oss.qualcomm.com>
Subject: Re: [PATCH v3 3/5] phy: qcom: qmp-usb-legacy: Fix possible NULL-deref on early runtime suspend
Date: Fri, 13 Feb 2026 10:02:44 +0100 [thread overview]
Message-ID: <aY7otFH-XdY0xwZu@hovoldconsulting.com> (raw)
In-Reply-To: <20260205160240.748371-4-loic.poulain@oss.qualcomm.com>
On Thu, Feb 05, 2026 at 05:02:38PM +0100, Loic Poulain wrote:
> There is a small window where the runtime suspend callback may run
> after pm_runtime_enable() and before pm_runtime_forbid(). In this
> case, a crash occurs because runtime suspend/resume dereferences
> qmp->phy pointer, which is not yet initialized:
> `if (!qmp->phy->init_count) {`
So here too, what would trigger a suspend in this window? (Except
possibly user space disabling and reenabling runtime pm, which can't
happen in practice).
> This can also happen if user re-enables runtime-pm via the sysfs
> attribute before qmp phy is initialized.
This I guess can happen in theory, but you'd need to try pretty hard.
But I think the commit message should better reflect this is all mostly
theoretical (currently it sounds like something you've actually hit).
Johan
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next prev parent reply other threads:[~2026-02-13 9:02 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-05 16:02 [PATCH v3 0/5] phy: qcom: Fix possible NULL-deref and runtime PM race conditions Loic Poulain
2026-02-05 16:02 ` [PATCH v3 1/5] phy: qcom: qmp-combo: Prevent unnecessary PM runtime suspend at boot Loic Poulain
2026-02-13 8:47 ` Johan Hovold
2026-02-05 16:02 ` [PATCH v3 2/5] phy: qcom: qmp-usbc: " Loic Poulain
2026-02-09 13:18 ` Dmitry Baryshkov
2026-02-05 16:02 ` [PATCH v3 3/5] phy: qcom: qmp-usb-legacy: Fix possible NULL-deref on early runtime suspend Loic Poulain
2026-02-09 13:18 ` Dmitry Baryshkov
2026-02-13 9:02 ` Johan Hovold [this message]
2026-02-05 16:02 ` [PATCH v3 4/5] phy: qcom: qmp-usb-legacy: Prevent unnecessary PM runtime suspend at boot Loic Poulain
2026-02-09 13:18 ` Dmitry Baryshkov
2026-02-05 16:02 ` [PATCH v3 5/5] phy: qcom: snps-femto-v2: Fix possible NULL-deref on early runtime suspend Loic Poulain
2026-02-13 9:07 ` Johan Hovold
2026-02-13 9:45 ` Loic Poulain
2026-02-13 10:45 ` Johan Hovold
2026-02-13 15:04 ` Loic Poulain
2026-02-13 20:15 ` Vladimir Oltean
2026-02-16 10:47 ` Johan Hovold
2026-02-17 10:40 ` Loic Poulain
2026-02-16 10:41 ` Johan Hovold
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