linux-kernel - [PATCH] devtmpfs: Replace simple_strtoul with kstrtoint in mount

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Message-ID: <20251220125930.76836-2-thorsten.blum@linux.dev>
Date: Sat, 20 Dec 2025 13:59:31 +0100
From: Thorsten Blum <thorsten.blum@...ux.dev>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	Danilo Krummrich <dakr@...nel.org>
Cc: Thorsten Blum <thorsten.blum@...ux.dev>,
	linux-kernel@...r.kernel.org
Subject: [PATCH] devtmpfs: Replace simple_strtoul with kstrtoint in mount_param

Replace simple_strtoul() with the recommended kstrtoint() for parsing
the 'devtmpfs.mount=' boot parameter. Unlike simple_strtoul(), which
returns an unsigned long, kstrtoint() converts the string directly to
int and avoids implicit casting.

Check the return value of kstrtoint() and reject invalid values. This
adds error handling while preserving behavior for existing values, and
removes use of the deprecated simple_strtoul() helper. The current code
silently sets 'mount_dev = 0' if parsing fails, instead of leaving the
default value (IS_ENABLED(CONFIG_DEVTMPFS_MOUNT)) unchanged.

Signed-off-by: Thorsten Blum <thorsten.blum@...ux.dev>
---
 drivers/base/devtmpfs.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 194b44075ac7..3f7d724ef242 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -56,8 +56,7 @@ static struct req {

 static int __init mount_param(char *str)
 {
-	mount_dev = simple_strtoul(str, NULL, 0);
-	return 1;
+	return kstrtoint(str, 0, &mount_dev) == 0;
 }
 __setup("devtmpfs.mount=", mount_param);

-- 
Thorsten Blum <thorsten.blum@...ux.dev>
GPG: 1D60 735E 8AEF 3BE4 73B6  9D84 7336 78FD 8DFE EAD4