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

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Message-ID: <CADLLry5J5GqB_Rw7n0aKcWgYPJZDOQP89mvyWT-GnB8KAiQrBA@mail.gmail.com>
Date:   Fri, 21 May 2021 15:55:23 +0900
From:   Austin Kim <austindh.kim@...il.com>
To:     Greg KH <gregkh@...uxfoundation.org>
Cc:     tj@...nel.org, neilb@...e.de, linux-kernel@...r.kernel.org,
        김동현 <austin.kim@....com>
Subject: Re: [PATCH] kernfs: move return value check after kmalloc()

2021년 5월 21일 (금) 오후 1:39, Greg KH <gregkh@...uxfoundation.org>님이 작성:
>
> On Fri, May 21, 2021 at 03:55:25AM +0100, Austin Kim wrote:
> > 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>
[...]
>
> Like Neil said, I don't see the "bug" you are fixing here.  What is
> currently wrong with the existing code?

I just found something to improve a little, which has nothing to do with 'Bug'.
(of->prealloc_buf is allocated ahead of kernfs_file_read_iter().)

Should be cautious of adding 'Fixes' tag.

Thanks

>
> thanks,
>
> greg k-h