linux-kernel - [PATCH] kernel/cpu.c: don't use snprintf() for sysfs attrs

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Date:   Mon, 24 Aug 2020 23:10:29 +0100
From:   Alex Dewar <alex.dewar90@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Alex Dewar <alex.dewar90@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Qais Yousef <qais.yousef@....com>,
        Peter Zijlstra <peterz@...radead.org>, Qian Cai <cai@....pw>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Arnd Bergmann <arnd@...db.de>,
        Tyler Hicks <tyhicks@...onical.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] kernel/cpu.c: don't use snprintf() for sysfs attrs

As per the documentation (Documentation/filesystems/sysfs.rst),
snprintf() should not be used for formatting values returned by sysfs.

In these two instances, we know that the string will be <PAGE_SIZE in
length, so just use sprintf().

Issue identified by Coccinelle.

Signed-off-by: Alex Dewar <alex.dewar90@...il.com>
---
 kernel/cpu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 6ff2578ecf17d..31694e02df958 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -2334,7 +2334,7 @@ show_smt_control(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	const char *state = smt_states[cpu_smt_control];
 
-	return snprintf(buf, PAGE_SIZE - 2, "%s\n", state);
+	return sprintf(buf, "%s\n", state);
 }
 
 static ssize_t
@@ -2348,7 +2348,7 @@ static DEVICE_ATTR(control, 0644, show_smt_control, store_smt_control);
 static ssize_t
 show_smt_active(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	return snprintf(buf, PAGE_SIZE - 2, "%d\n", sched_smt_active());
+	return sprintf(buf, "%d\n", sched_smt_active());
 }
 static DEVICE_ATTR(active, 0444, show_smt_active, NULL);
 
-- 
2.28.0