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From: Linus Walleij <linus.walleij@linaro.org>
To: Praveen Talari <praveen.talari@oss.qualcomm.com>
Cc: Bjorn Andersson <andersson@kernel.org>,
	Konrad Dybcio <konradybcio@kernel.org>,
	 Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	 Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>,
	 Dmitry Baryshkov <lumag@kernel.org>,
	linux-arm-msm@vger.kernel.org,  devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org,  linux-gpio@vger.kernel.org,
	linux-serial@vger.kernel.org,  alexey.klimov@linaro.org,
	krzk@kernel.org, bryan.odonoghue@linaro.org,
	 jorge.ramirez@oss.qualcomm.com,
	dmitry.baryshkov@oss.qualcomm.com,
	 Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>,
	psodagud@quicinc.com, djaggi@quicinc.com,
	 quic_msavaliy@quicinc.com, quic_vtanuku@quicinc.com,
	 quic_arandive@quicinc.com, quic_shazhuss@quicinc.com,
	 quic_cchiluve@quicinc.com,
	Prasad Sodagudi <prasad.sodagudi@oss.qualcomm.com>
Subject: Re: [PATCH v1 2/4] pinctrl: qcom: msm: Fix potential deadlock in pinmux configuration
Date: Wed, 12 Nov 2025 13:43:30 +0100	[thread overview]
Message-ID: <CACRpkdYEbxtjoi8KQxS5fY6xr3UZwQmG-yKvT3L8fRcCXDaAwQ@mail.gmail.com> (raw)
In-Reply-To: <20251110101043.2108414-3-praveen.talari@oss.qualcomm.com>

Hi Praveen,

thanks for your patch!

On Mon, Nov 10, 2025 at 11:11 AM Praveen Talari
<praveen.talari@oss.qualcomm.com> wrote:

> Replace disable_irq() with disable_irq_nosync() in msm_pinmux_set_mux()
> to prevent potential deadlock when wakeup IRQ is triggered on the same
> GPIO being reconfigured.
>
> The issue occurs when a wakeup IRQ is triggered on a GPIO and the IRQ
> handler attempts to reconfigure the same GPIO's pinmux. In this scenario,
> msm_pinmux_set_mux() calls disable_irq() which waits for the currently
> running IRQ handler to complete, creating a circular dependency that
> results in deadlock.
>
> Using disable_irq_nosync() avoids waiting for the IRQ handler to
> complete, preventing the deadlock condition while still properly
> disabling the interrupt during pinmux reconfiguration.
>
> Suggested-by: Prasad Sodagudi <prasad.sodagudi@oss.qualcomm.com>
> Signed-off-by: Praveen Talari <praveen.talari@oss.qualcomm.com>

I applied this patch 2/4 to the pin control tree for fixes.

I removed the word "potential" from subject and text so as to
reflect what Bjorn is saying: it's a very real issue.

Thanks for fixing this!
Linus Walleij

  parent reply	other threads:[~2025-11-12 12:43 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-10 10:10 [PATCH v1 0/4] Enable Serial on SA8255p Qualcomm platforms Praveen Talari
2025-11-10 10:10 ` [PATCH v1 1/4] arm64: dts: qcom: qrb2210-rb1: Fix UART3 wakeup IRQ storm Praveen Talari
2025-11-10 11:10   ` Konrad Dybcio
2025-11-10 10:10 ` [PATCH v1 2/4] pinctrl: qcom: msm: Fix potential deadlock in pinmux configuration Praveen Talari
2025-11-11  4:08   ` Bjorn Andersson
2025-11-11  5:22     ` Praveen Talari
2025-11-11 15:35       ` Bjorn Andersson
2025-11-12 12:43   ` Linus Walleij [this message]
2025-11-10 10:10 ` [PATCH v1 3/4] serial: qcom-geni: Enable PM runtime for serial driver Praveen Talari
2025-11-26 13:01   ` Andy Shevchenko
2025-11-10 10:10 ` [PATCH v1 4/4] serial: qcom-geni: Enable Serial on SA8255p Qualcomm platforms Praveen Talari
2025-11-26 13:06   ` Andy Shevchenko
2025-11-14  0:18 ` (subset) [PATCH v1 0/4] " Bjorn Andersson

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