From:   Thomas Zimmermann <tzimmermann@suse.de>
To:     deller@gmx.de, geert+renesas@glider.be, timur@kernel.org,
        rdunlap@infradead.org, paulus@samba.org, benh@kernel.crashing.org,
        linux@armlinux.org.uk, pjones@redhat.com, adaplas@gmail.com,
        s.hauer@pengutronix.de, shawnguo@kernel.org, mbroemme@libmpq.org,
        thomas@winischhofer.net, James.Bottomley@HansenPartnership.com,
        sudipm.mukherjee@gmail.com, teddy.wang@siliconmotion.com,
        corbet@lwn.net
Cc:     linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org,
        Thomas Zimmermann <tzimmermann@suse.de>
Subject: [PATCH v2 050/101] fbdev/nvidiafb: Duplicate video-mode option string
Date:   Thu,  9 Mar 2023 17:01:10 +0100
Message-Id: <20230309160201.5163-51-tzimmermann@suse.de>
In-Reply-To: <20230309160201.5163-1-tzimmermann@suse.de>
References: <20230309160201.5163-1-tzimmermann@suse.de>
MIME-Version: 1.0
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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@suse.de>
---
 drivers/video/fbdev/nvidia/nvidia.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/video/fbdev/nvidia/nvidia.c b/drivers/video/fbdev/nvidia/nvidia.c
index e60a276b4855..8ad4bcff84df 100644
--- a/drivers/video/fbdev/nvidia/nvidia.c
+++ b/drivers/video/fbdev/nvidia/nvidia.c
@@ -77,6 +77,7 @@ static int reverse_i2c;
 static bool nomtrr = false;
 static int backlight = IS_BUILTIN(CONFIG_PMAC_BACKLIGHT);
 
+static char *mode_option_buf;
 static char *mode_option = NULL;
 
 static struct fb_fix_screeninfo nvidiafb_fix = {
@@ -1498,8 +1499,11 @@ static int nvidiafb_setup(char *options)
 			fpdither = simple_strtol(this_opt+9, NULL, 0);
 		} else if (!strncmp(this_opt, "bpp:", 4)) {
 			bpp = simple_strtoul(this_opt+4, NULL, 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;
+		}
 	}
 	NVTRACE_LEAVE();
 	return 0;
@@ -1542,6 +1546,7 @@ module_init(nvidiafb_init);
 static void __exit nvidiafb_exit(void)
 {
 	pci_unregister_driver(&nvidiafb_driver);
+	kfree(mode_option_buf);
 }
 
 module_exit(nvidiafb_exit);
-- 
2.39.2