linux-kernel - [PATCH] kernfs: move return value check after kmalloc()

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Message-ID: <20210521025525.GA1379@raspberrypi>
Date:   Fri, 21 May 2021 03:55:25 +0100
From:   Austin Kim <austindh.kim@...il.com>
To:     gregkh@...uxfoundation.org, tj@...nel.org, neilb@...e.de
Cc:     linux-kernel@...r.kernel.org, austin.kim@....com,
        austindh.kim@...il.com
Subject: [PATCH] kernfs: move return value check after kmalloc()

With 414985ae23c0 ("sysfs, kernfs: move file core code to fs/kernfs/file.c"),
'return -ENOMEM' is executed when kmalloc() returns NULL.

Since 'commit 4ef67a8c95f3 ("sysfs/kernfs: make read requests on pre-alloc
files use the buffer.")', 'return -ENOMEM' statement is not properly located.

Fix it by moving 'return -ENOMEM' after return from kmalloc().

Fixes: 4ef67a8c95f3 ("sysfs/kernfs: make read requests on pre-alloc files use the buffer.")
Signed-off-by: Austin Kim <austindh.kim@...il.com>
---
 fs/kernfs/file.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index c75719312147..c5e2429af836 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -191,10 +191,11 @@ static ssize_t kernfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 	buf = of->prealloc_buf;
 	if (buf)
 		mutex_lock(&of->prealloc_mutex);
-	else
+	else {
 		buf = kmalloc(len, GFP_KERNEL);
-	if (!buf)
-		return -ENOMEM;
+		if (!buf)
+			return -ENOMEM;
+	}
 
 	/*
 	 * @of->mutex nests outside active ref and is used both to ensure that
-- 
2.20.1