From: Bart Van Assche <bvanassche@acm.org>
Date: Fri, 7 Feb 2025 16:25:27 +0000 (-0500)
Subject: drm: zynqmp_dp: Fix a deadlock in zynqmp_dp_ignore_hpd_set()
X-Git-Tag: v6.15-rc1~120^2~19^2~73
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f887685ee0eb4ef716391355568181230338f6eb;p=thirdparty%2Fkernel%2Flinux.git

drm: zynqmp_dp: Fix a deadlock in zynqmp_dp_ignore_hpd_set()

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>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sean Anderson <sean.anderson@seco.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250207162528.1651426-2-sean.anderson@linux.dev
---

diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
index 979f6d3239ba6..189a08cdc73c0 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;
 }