linux-kernel - [PATCH 26/99] fbdev/geode: Duplicate video-mode option string

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Date:   Mon,  6 Mar 2023 16:59:03 +0100
From:   Thomas Zimmermann <tzimmermann@...e.de>
To:     deller@....de, paulus@...ba.org, benh@...nel.crashing.org,
        linux@...linux.org.uk, pjones@...hat.com, timur@...nel.org,
        adaplas@...il.com, s.hauer@...gutronix.de, shawnguo@...nel.org,
        mbroemme@...mpq.org, thomas@...ischhofer.net,
        James.Bottomley@...senPartnership.com, spock@...too.org,
        sudipm.mukherjee@...il.com, teddy.wang@...iconmotion.com,
        geert+renesas@...der.be, corbet@....net
Cc:     linux-fbdev@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org,
        Thomas Zimmermann <tzimmermann@...e.de>
Subject: [PATCH 26/99] fbdev/geode: Duplicate video-mode option string

Assume that the driver does not own the option string or its substrings
and hence duplicate the option string for the video mode. The driver only
parses the option string once as part of module initialization, so use
a static buffer to store the duplicated mode option. Linux automatically
frees the memory upon releasing the module.

Done in preparation of switching the driver to struct option_iter and
constifying the option string.

Signed-off-by: Thomas Zimmermann <tzimmermann@...e.de>
---
 drivers/video/fbdev/geode/gxfb_core.c | 10 +++++++++-
 drivers/video/fbdev/geode/lxfb_core.c | 13 +++++++++++--
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/video/fbdev/geode/gxfb_core.c b/drivers/video/fbdev/geode/gxfb_core.c
index 8e05e76de075..3ed85d2d53e9 100644
--- a/drivers/video/fbdev/geode/gxfb_core.c
+++ b/drivers/video/fbdev/geode/gxfb_core.c
@@ -497,10 +497,18 @@ static int __init gxfb_setup(char *options)
 		return 0;
 
 	while ((opt = strsep(&options, ",")) != NULL) {
+		static char mode_option_buf[256];
+		int ret;
+
 		if (!*opt)
 			continue;
 
-		mode_option = opt;
+		ret = snprintf(mode_option_buf, sizeof(mode_option_buf), "%s", opt);
+		if (WARN(ret < 0, "gxfb: ignoring invalid option, ret=%d\n", ret))
+			continue;
+		if (WARN(ret >= sizeof(mode_option_buf), "gxfb: option too long\n"))
+			continue;
+		mode_option = mode_option_buf;
 	}
 
 	return 0;
diff --git a/drivers/video/fbdev/geode/lxfb_core.c b/drivers/video/fbdev/geode/lxfb_core.c
index 8130e9eee2b4..6e1e73a21bdb 100644
--- a/drivers/video/fbdev/geode/lxfb_core.c
+++ b/drivers/video/fbdev/geode/lxfb_core.c
@@ -635,8 +635,17 @@ static int __init lxfb_setup(char *options)
 			nopanel = 1;
 		else if (!strcmp(opt, "nocrt"))
 			nocrt = 1;
-		else
-			mode_option = opt;
+		else {
+			static char mode_option_buf[256];
+			int ret;
+
+			ret = snprintf(mode_option_buf, sizeof(mode_option_buf), "%s", opt);
+			if (WARN(ret < 0, "lxfb: ignoring invalid option, ret=%d\n", ret))
+				continue;
+			if (WARN(ret >= sizeof(mode_option_buf), "lxfb: option too long\n"))
+				continue;
+			mode_option = mode_option_buf;
+		}
 	}
 
 	return 0;
-- 
2.39.2