netdev - [PATCH v4 07/11] mm/kmemleak: Replace strncpy() with __get_task

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Message-Id: <20240628090517.17994-7-laoar.shao@gmail.com>
Date: Fri, 28 Jun 2024 17:05:13 +0800
From: Yafang Shao <laoar.shao@...il.com>
To: torvalds@...ux-foundation.org,
	laoar.shao@...il.com
Cc: akpm@...ux-foundation.org,
	alexei.starovoitov@...il.com,
	audit@...r.kernel.org,
	bpf@...r.kernel.org,
	catalin.marinas@....com,
	dri-devel@...ts.freedesktop.org,
	ebiederm@...ssion.com,
	linux-fsdevel@...r.kernel.org,
	linux-mm@...ck.org,
	linux-security-module@...r.kernel.org,
	linux-trace-kernel@...r.kernel.org,
	netdev@...r.kernel.org,
	penguin-kernel@...ove.sakura.ne.jp,
	rostedt@...dmis.org,
	selinux@...r.kernel.org
Subject: [PATCH v4 07/11] mm/kmemleak: Replace strncpy() with __get_task_comm()

Since task lock was dropped from __get_task_comm(), it's safe to call it
from kmemleak.

Using __get_task_comm() to read the task comm ensures that the name is
always NUL-terminated, regardless of the source string. This approach also
facilitates future extensions to the task comm.

Signed-off-by: Yafang Shao <laoar.shao@...il.com>
Acked-by: Catalin Marinas <catalin.marinas@....com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
---
 mm/kmemleak.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index d5b6fba44fc9..ef29aaab88a0 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -663,13 +663,7 @@ static struct kmemleak_object *__alloc_object(gfp_t gfp)
 		strncpy(object->comm, "softirq", sizeof(object->comm));
 	} else {
 		object->pid = current->pid;
-		/*
-		 * There is a small chance of a race with set_task_comm(),
-		 * however using get_task_comm() here may cause locking
-		 * dependency issues with current->alloc_lock. In the worst
-		 * case, the command line is not correct.
-		 */
-		strncpy(object->comm, current->comm, sizeof(object->comm));
+		__get_task_comm(object->comm, sizeof(object->comm), current);
 	}
 
 	/* kernel backtrace */
-- 
2.43.5