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From: Sean Anderson <sean.anderson@linux.dev>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>,
	dri-devel@lists.freedesktop.org (open list:DRM DRIVERS FOR
	XILINX)
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	David Airlie <airlied@gmail.com>, Simona Vetter <simona@ffwll.ch>,
	Michal Simek <michal.simek@amd.com>,
	Maxime Ripard <mripard@kernel.org>,
	linux-kernel@vger.kernel.org (open list),
	Thomas Zimmermann <tzimmermann@suse.de>,
	Bart Van Assche <bvanassche@acm.org>,
	Dan Carpenter <dan.carpenter@linaro.org>,
	linux-arm-kernel@lists.infradead.org (moderated list:ARM/ZYNQ
	ARCHITECTURE), Sean Anderson <sean.anderson@linux.dev>
Subject: [PATCH v2 1/2] drm: zynqmp_dp: Fix a deadlock in zynqmp_dp_ignore_hpd_set()
Date: Fri,  7 Feb 2025 11:25:27 -0500	[thread overview]
Message-ID: <20250207162528.1651426-2-sean.anderson@linux.dev> (raw)
In-Reply-To: <20250207162528.1651426-1-sean.anderson@linux.dev>

From: Bart Van Assche <bvanassche@acm.org>

Instead of attempting the same mutex twice, lock and unlock it.

This bug has been detected by the Clang thread-safety analyzer.

Cc: Sean Anderson <sean.anderson@linux.dev>
Cc: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Fixes: 28edaacb821c ("drm: zynqmp_dp: Add debugfs interface for compliance testing")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Sean Anderson <sean.anderson@linux.dev>
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
---

(no changes since v1)

 drivers/gpu/drm/xlnx/zynqmp_dp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
index 979f6d3239ba..189a08cdc73c 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
@@ -2295,7 +2295,7 @@ static int zynqmp_dp_ignore_hpd_set(void *data, u64 val)
 
 	mutex_lock(&dp->lock);
 	dp->ignore_hpd = val;
-	mutex_lock(&dp->lock);
+	mutex_unlock(&dp->lock);
 	return 0;
 }
 
-- 
2.35.1.1320.gc452695387.dirty



  reply	other threads:[~2025-02-07 16:28 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-07 16:25 [PATCH v2 0/2] drm: zynqmp_dp: Use scope-based mutex helpers Sean Anderson
2025-02-07 16:25 ` Sean Anderson [this message]
2025-02-07 16:33   ` [PATCH v2 1/2] drm: zynqmp_dp: Fix a deadlock in zynqmp_dp_ignore_hpd_set() Laurent Pinchart
2025-02-07 16:25 ` [PATCH v2 2/2] drm: zynqmp_dp: Use scope-based mutex helpers Sean Anderson
2025-02-07 16:44   ` Laurent Pinchart
2025-02-07 17:06     ` Sean Anderson
2025-02-12  8:01 ` [PATCH v2 0/2] " Tomi Valkeinen

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