linux-kernel - [PATCH 3/5] kernel/sched: improve the BUILD_BUG_ON() in get_task

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Message-Id: <20210929115036.4851-4-laoar.shao@gmail.com>
Date:   Wed, 29 Sep 2021 11:50:34 +0000
From:   Yafang Shao <laoar.shao@...il.com>
To:     akpm@...ux-foundation.org, pmladek@...e.com, peterz@...radead.org,
        valentin.schneider@....com, keescook@...omium.org,
        mathieu.desnoyers@...icios.com, qiang.zhang@...driver.com,
        robdclark@...omium.org, viro@...iv.linux.org.uk,
        christian@...uner.io, dietmar.eggemann@....com
Cc:     linux-kernel@...r.kernel.org, Yafang Shao <laoar.shao@...il.com>
Subject: [PATCH 3/5] kernel/sched: improve the BUILD_BUG_ON() in get_task_comm()

What we really want to guarantee is that the buf size can't be less than
TASK_COMM_LEN. While the size be greater than TASK_COMM_LEN is
acceptable.

Signed-off-by: Yafang Shao <laoar.shao@...il.com>
---
 include/linux/sched.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index b387b5943db4..959eaef248fc 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1931,7 +1931,7 @@ static inline void set_task_comm(struct task_struct *tsk, const char *from)
 
 extern char *__get_task_comm(char *to, size_t len, struct task_struct *tsk);
 #define get_task_comm(buf, tsk) ({			\
-	BUILD_BUG_ON(sizeof(buf) != TASK_COMM_LEN);	\
+	BUILD_BUG_ON(sizeof(buf) < TASK_COMM_LEN);	\
 	__get_task_comm(buf, sizeof(buf), tsk);		\
 })
 
-- 
2.17.1