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From: Greg KH <gregkh@linuxfoundation.org>
To: "yekai(A)" <yekai13@huawei.com>
Cc: linux-accelerators@lists.ozlabs.org,
	linux-kernel@vger.kernel.org, linuxarm@huawei.com,
	zhangfei.gao@linaro.org, wangzhou1@hisilicon.com
Subject: Re: [PATCH] uacce: use sysfs_emit instead of sprintf
Date: Mon, 17 May 2021 13:56:35 +0200	[thread overview]
Message-ID: <YKJZ8278k0GEcF87@kroah.com> (raw)
In-Reply-To: <e5290000-5481-c662-974f-85eea7660953@huawei.com>

On Mon, May 17, 2021 at 07:49:37PM +0800, yekai(A) wrote:
> 
> 
> On 2021/5/17 18:36, Greg KH wrote:
> > On Mon, May 17, 2021 at 06:25:37PM +0800, Kai Ye wrote:
> > > Use the sysfs_emit to replace sprintf.
> > 
> > That says _what_ you did, not _why_ you are doing this.  What problem
> > are you solving with this change?
> > 
> > thanks,
> > 
> > greg k-h
> > .
> > 
> sprintf is not safe, and it not recommended to use.

Why not?  What is "unsafe" with it in this function?

> sprintf does not know the PAGE_SIZE maximum of the temporary buffer
> used for outputting sysfs content and it's possible to overrun the
> PAGE_SIZE buffer length. so used sysfs_emit that  knows that the size
> of the call situations that also ensures that no overrun is done. so use
> sysfs_emit to replace sprintf maybe better.

But that's not a problem at all for these calls, right?  If so, please
show me how that could ever happen.

thanks,

greg k-h

      reply	other threads:[~2021-05-17 11:56 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-17 10:25 [PATCH] uacce: use sysfs_emit instead of sprintf Kai Ye
2021-05-17 10:36 ` Greg KH
2021-05-17 11:49   ` yekai(A)
2021-05-17 11:56     ` Greg KH [this message]

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