linux-kernel - [PATCH v2 094/101] fbdev/vfb: Duplicate video-mode option string

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Message-Id: <20230309160201.5163-95-tzimmermann@suse.de>
Date:   Thu,  9 Mar 2023 17:01:54 +0100
From:   Thomas Zimmermann <tzimmermann@...e.de>
To:     deller@....de, geert+renesas@...der.be, timur@...nel.org,
        rdunlap@...radead.org, paulus@...ba.org, benh@...nel.crashing.org,
        linux@...linux.org.uk, pjones@...hat.com, adaplas@...il.com,
        s.hauer@...gutronix.de, shawnguo@...nel.org, mbroemme@...mpq.org,
        thomas@...ischhofer.net, James.Bottomley@...senPartnership.com,
        sudipm.mukherjee@...il.com, teddy.wang@...iconmotion.com,
        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 v2 094/101] fbdev/vfb: 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. Allocate the
copy's memory with kstrdup() and free it in the module's exit function.

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

v2:
	* replace static memory with kstrdup()/kfree() (Geert)

Signed-off-by: Thomas Zimmermann <tzimmermann@...e.de>
---
 drivers/video/fbdev/vfb.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/video/fbdev/vfb.c b/drivers/video/fbdev/vfb.c
index 680c88267ef4..de27fe84d820 100644
--- a/drivers/video/fbdev/vfb.c
+++ b/drivers/video/fbdev/vfb.c
@@ -37,6 +37,7 @@ static u_long videomemorysize = VIDEOMEMSIZE;
 module_param(videomemorysize, ulong, 0);
 MODULE_PARM_DESC(videomemorysize, "RAM available to frame buffer (in bytes)");
 
+static char *mode_option_buf;
 static char *mode_option = NULL;
 module_param(mode_option, charp, 0);
 MODULE_PARM_DESC(mode_option, "Preferred video mode (e.g. 640x480-8@60)");
@@ -412,8 +413,11 @@ static int __init vfb_setup(char *options)
 		/* Test disable for backwards compatibility */
 		if (!strcmp(this_opt, "disable"))
 			vfb_enable = 0;
-		else
-			mode_option = this_opt;
+		else {
+			kfree(mode_option_buf);
+			mode_option_buf = kstrdup(this_opt, GFP_KERNEL); // ignore errors
+			mode_option = mode_option_buf;
+		}
 	}
 	return 1;
 }
@@ -543,6 +547,7 @@ static void __exit vfb_exit(void)
 {
 	platform_device_unregister(vfb_device);
 	platform_driver_unregister(&vfb_driver);
+	kfree(mode_option_buf);
 }
 
 module_exit(vfb_exit);
-- 
2.39.2