linux-kernel - [tip: sched/core] sched/debug: Convert copy_from_user() + kstrtouint() to kstrtouint_from

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Message-ID: <176907697014.510.1378420592339878350.tip-bot2@tip-bot2>
Date: Thu, 22 Jan 2026 10:16:10 -0000
From: "tip-bot2 for Fushuai Wang" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Yury Norov <ynorov@...dia.com>, Fushuai Wang <wangfushuai@...du.com>,
 "Peter Zijlstra (Intel)" <peterz@...radead.org>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: sched/core] sched/debug: Convert copy_from_user() +
 kstrtouint() to kstrtouint_from_user()

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     4fe82cf3024a4bdd2571d584efc25598533d5c96
Gitweb:        https://git.kernel.org/tip/4fe82cf3024a4bdd2571d584efc25598533d5c96
Author:        Fushuai Wang <wangfushuai@...du.com>
AuthorDate:    Sat, 17 Jan 2026 22:56:14 +08:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Thu, 22 Jan 2026 11:11:16 +01:00

sched/debug: Convert copy_from_user() + kstrtouint() to kstrtouint_from_user()

Using kstrtouint_from_user() instead of copy_from_user() + kstrtouint()
makes the code simpler and less error-prone.

Suggested-by: Yury Norov <ynorov@...dia.com>
Signed-off-by: Fushuai Wang <wangfushuai@...du.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Yury Norov <ynorov@...dia.com>
Link: https://patch.msgid.link/20260117145615.53455-2-fushuai.wang@linux.dev
---
 kernel/sched/debug.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 5f9b771..929fdf0 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -172,18 +172,12 @@ static const struct file_operations sched_feat_fops = {
 static ssize_t sched_scaling_write(struct file *filp, const char __user *ubuf,
 				   size_t cnt, loff_t *ppos)
 {
-	char buf[16];
 	unsigned int scaling;
+	int ret;
 
-	if (cnt > 15)
-		cnt = 15;
-
-	if (copy_from_user(&buf, ubuf, cnt))
-		return -EFAULT;
-	buf[cnt] = '\0';
-
-	if (kstrtouint(buf, 10, &scaling))
-		return -EINVAL;
+	ret = kstrtouint_from_user(ubuf, cnt, 10, &scaling);
+	if (ret)
+		return ret;
 
 	if (scaling >= SCHED_TUNABLESCALING_END)
 		return -EINVAL;