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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-aspeed@lists.ozlabs.org
Subject: [PATCH] tty: 8250: replace snprintf in show functions with sysfs_emit
Date: Fri, 15 Oct 2021 08:57:56 +0200	[thread overview]
Message-ID: <YWkmdELuWa6ITIIR@kroah.com> (raw)
In-Reply-To: <1634280682-5002-1-git-send-email-wangqing@vivo.com>

On Thu, Oct 14, 2021 at 11:51:22PM -0700, Qing Wang wrote:
> show() must not use snprintf() when formatting the value to be
> returned to user space.

Why must it not?  What is broken in the existing code?

> 
> Fix the coccicheck warnings:
> WARNING: use scnprintf or sprintf.
> 
> Signed-off-by: Qing Wang <wangqing@vivo.com>
> ---
>  drivers/tty/serial/8250/8250_aspeed_vuart.c | 6 +++---
>  drivers/tty/serial/8250/8250_port.c         | 2 +-
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_aspeed_vuart.c b/drivers/tty/serial/8250/8250_aspeed_vuart.c
> index 2350fb3..082b9bd 100644
> --- a/drivers/tty/serial/8250/8250_aspeed_vuart.c
> +++ b/drivers/tty/serial/8250/8250_aspeed_vuart.c
> @@ -82,7 +82,7 @@ static ssize_t lpc_address_show(struct device *dev,
>  	addr = (aspeed_vuart_readb(vuart, ASPEED_VUART_ADDRH) << 8) |
>  		(aspeed_vuart_readb(vuart, ASPEED_VUART_ADDRL));
>  
> -	return snprintf(buf, PAGE_SIZE - 1, "0x%x\n", addr);
> +	return sysfs_emit(buf - 1, "0x%x\n", addr);

what is the buf-1 thing here for?

Doing a tree-wide change for this type of thing might not be wanted by
many maintainers, especially if you introduce bugs like this :(

greg k-h

WARNING: multiple messages have this Message-ID (diff)
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Qing Wang <wangqing@vivo.com>
Cc: Jiri Slaby <jirislaby@kernel.org>, Joel Stanley <joel@jms.id.au>,
	Andrew Jeffery <andrew@aj.id.au>,
	linux-serial@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tty: 8250: replace snprintf in show functions with sysfs_emit
Date: Fri, 15 Oct 2021 08:57:56 +0200	[thread overview]
Message-ID: <YWkmdELuWa6ITIIR@kroah.com> (raw)
In-Reply-To: <1634280682-5002-1-git-send-email-wangqing@vivo.com>

On Thu, Oct 14, 2021 at 11:51:22PM -0700, Qing Wang wrote:
> show() must not use snprintf() when formatting the value to be
> returned to user space.

Why must it not?  What is broken in the existing code?

> 
> Fix the coccicheck warnings:
> WARNING: use scnprintf or sprintf.
> 
> Signed-off-by: Qing Wang <wangqing@vivo.com>
> ---
>  drivers/tty/serial/8250/8250_aspeed_vuart.c | 6 +++---
>  drivers/tty/serial/8250/8250_port.c         | 2 +-
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_aspeed_vuart.c b/drivers/tty/serial/8250/8250_aspeed_vuart.c
> index 2350fb3..082b9bd 100644
> --- a/drivers/tty/serial/8250/8250_aspeed_vuart.c
> +++ b/drivers/tty/serial/8250/8250_aspeed_vuart.c
> @@ -82,7 +82,7 @@ static ssize_t lpc_address_show(struct device *dev,
>  	addr = (aspeed_vuart_readb(vuart, ASPEED_VUART_ADDRH) << 8) |
>  		(aspeed_vuart_readb(vuart, ASPEED_VUART_ADDRL));
>  
> -	return snprintf(buf, PAGE_SIZE - 1, "0x%x\n", addr);
> +	return sysfs_emit(buf - 1, "0x%x\n", addr);

what is the buf-1 thing here for?

Doing a tree-wide change for this type of thing might not be wanted by
many maintainers, especially if you introduce bugs like this :(

greg k-h

WARNING: multiple messages have this Message-ID (diff)
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Qing Wang <wangqing@vivo.com>
Cc: Jiri Slaby <jirislaby@kernel.org>, Joel Stanley <joel@jms.id.au>,
	Andrew Jeffery <andrew@aj.id.au>,
	linux-serial@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tty: 8250: replace snprintf in show functions with sysfs_emit
Date: Fri, 15 Oct 2021 08:57:56 +0200	[thread overview]
Message-ID: <YWkmdELuWa6ITIIR@kroah.com> (raw)
In-Reply-To: <1634280682-5002-1-git-send-email-wangqing@vivo.com>

On Thu, Oct 14, 2021 at 11:51:22PM -0700, Qing Wang wrote:
> show() must not use snprintf() when formatting the value to be
> returned to user space.

Why must it not?  What is broken in the existing code?

> 
> Fix the coccicheck warnings:
> WARNING: use scnprintf or sprintf.
> 
> Signed-off-by: Qing Wang <wangqing@vivo.com>
> ---
>  drivers/tty/serial/8250/8250_aspeed_vuart.c | 6 +++---
>  drivers/tty/serial/8250/8250_port.c         | 2 +-
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_aspeed_vuart.c b/drivers/tty/serial/8250/8250_aspeed_vuart.c
> index 2350fb3..082b9bd 100644
> --- a/drivers/tty/serial/8250/8250_aspeed_vuart.c
> +++ b/drivers/tty/serial/8250/8250_aspeed_vuart.c
> @@ -82,7 +82,7 @@ static ssize_t lpc_address_show(struct device *dev,
>  	addr = (aspeed_vuart_readb(vuart, ASPEED_VUART_ADDRH) << 8) |
>  		(aspeed_vuart_readb(vuart, ASPEED_VUART_ADDRL));
>  
> -	return snprintf(buf, PAGE_SIZE - 1, "0x%x\n", addr);
> +	return sysfs_emit(buf - 1, "0x%x\n", addr);

what is the buf-1 thing here for?

Doing a tree-wide change for this type of thing might not be wanted by
many maintainers, especially if you introduce bugs like this :(

greg k-h

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2021-10-15  6:57 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-15  6:51 [PATCH] tty: 8250: replace snprintf in show functions with sysfs_emit Qing Wang
2021-10-15  6:51 ` Qing Wang
2021-10-15  6:51 ` Qing Wang
2021-10-15  6:57 ` Greg Kroah-Hartman [this message]
2021-10-15  6:57   ` Greg Kroah-Hartman
2021-10-15  6:57   ` Greg Kroah-Hartman
     [not found] ` <AOQACwDzEi5UM3m3ezm-D4o5.9.1634281082401.Hmail.wangqing@vivo.com>
2021-10-15  7:13   ` 回复: " 王擎
2021-10-15  7:13     ` 王擎
2021-10-15  7:13     ` 王擎

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