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[13.212.242.176]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3a088cf5b02sm1534349a91.14.2026.09.23.01.44.07 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Wed, 23 Sep 2026 01:44:08 -0700 (PDT) From: Ginger Li To: claudiu.beznea@tuxon.dev, broonie@kernel.org Cc: linux-sound@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] ASoC: mchp-spdiftx: Fix a deadlock with the interrupt handler Date: Wed, 23 Sep 2026 16:44:01 +0800 Message-ID: <20260923084401.65336-1-ginger.jzllee@gmail.com> X-Mailer: git-send-email 2.46.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" mchp_spdiftx_interrupt() is a hardirq handler and takes ctrl->lock to serialize the user data and channel status updates, while mchp_spdiftx_trigger() takes the same lock with spin_lock() from process context. Interrupts stay enabled while the lock is held in mchp_spdiftx_trigger(), so if an SPDIFTX interrupt is delivered on the CPU that is inside that critical section, the hardirq handler spins on a lock that the interrupted code is holding and can never release. Take ctrl->lock with spin_lock_irqsave() in mchp_spdiftx_trigger(), like the other process context users of this lock in the driver already do. Fixes: 06ca24e98e6b ("ASoC: mchp-spdiftx: add driver for S/PDIF TX Controll= er") Signed-off-by: Ginger Li --- sound/soc/atmel/mchp-spdiftx.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/sound/soc/atmel/mchp-spdiftx.c b/sound/soc/atmel/mchp-spdiftx.c --- a/sound/soc/atmel/mchp-spdiftx.c +++ b/sound/soc/atmel/mchp-spdiftx.c @@ -306,10 +306,11 @@ static int mchp_spdiftx_trigger(struct snd_pcm_substre { struct mchp_spdiftx_dev *dev =3D snd_soc_dai_get_drvdata(dai); struct mchp_spdiftx_mixer_control *ctrl =3D &dev->control; + unsigned long flags; int ret; =20 /* do not start/stop while channel status or user data is updated */ - spin_lock(&ctrl->lock); + spin_lock_irqsave(&ctrl->lock, flags); switch (cmd) { case SNDRV_PCM_TRIGGER_RESUME: case SNDRV_PCM_TRIGGER_START: @@ -335,7 +336,7 @@ static int mchp_spdiftx_trigger(struct snd_pcm_substre default: ret =3D -EINVAL; } - spin_unlock(&ctrl->lock); + spin_unlock_irqrestore(&ctrl->lock, flags); if (ret) dev_err(dev->dev, "unable to start/stop TX: %d\n", ret); =20 --=20 2.43.0