From b662b162c3d06f120749eea0351ec9317d9dd905 Mon Sep 17 00:00:00 2001
From: Feng Jiang <jiangfeng@kylinos.cn>
Date: Wed, 9 Apr 2025 09:46:33 +0800
Subject: [PATCH 3459/5403] drm: Fix potential overflow issue in event_string
 array
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When calling scnprintf() to append recovery method to event_string,
the second argument should be `sizeof(event_string) - len`, otherwise
there is a potential overflow problem.

Fixes: b7cf9f4ac1b8 ("drm: Introduce device wedged event")
Signed-off-by: Feng Jiang <jiangfeng@kylinos.cn>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Reviewed-by: Raag Jadav <raag.jadav@intel.com>
Link: https://lore.kernel.org/r/20250409014633.31303-1-jiangfeng@kylinos.cn
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
---
 drivers/gpu/drm/drm_drv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 17fc5dc708f4..60e5ac179c15 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -549,7 +549,7 @@ int drm_dev_wedged_event(struct drm_device *dev, unsigned long method)
 		if (drm_WARN_ONCE(dev, !recovery, "invalid recovery method %u\n", opt))
 			break;
 
-		len += scnprintf(event_string + len, sizeof(event_string), "%s,", recovery);
+		len += scnprintf(event_string + len, sizeof(event_string) - len, "%s,", recovery);
 	}
 
 	if (recovery)
-- 
2.54.0

