linux-kernel - Re: [PATCH v3 1/1] tty: serial: samsung: add spin_lock for interrupt and console

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <b53be23f-7935-dae3-9dc8-f850493a5fa9@kernel.org>
Date:   Thu, 7 Apr 2022 09:46:46 +0200
From:   Jiri Slaby <jirislaby@...nel.org>
To:     Jaewon Kim <jaewon02.kim@...sung.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Alim Akhtar <alim.akhtar@...sung.com>,
        linux-samsung-soc@...r.kernel.org
Cc:     linux-arm-kernel@...ts.infradead.org, linux-serial@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Chanho Park <chanho61.park@...sung.com>
Subject: Re: [PATCH v3 1/1] tty: serial: samsung: add spin_lock for interrupt
 and console_write

On 07. 04. 22, 9:16, Jaewon Kim wrote:
> The console_write and IRQ handler can run concurrently.
> Problems may occurs console_write is continuously executed while
> the IRQ handler is running.

 From the patch POV:

Reviewed-by: Jiri Slaby <jirislaby@...nel.org>

But given this is a v3 with no version changelog below "---", you've 
just kicked the Greg's bot to wake up :P.

> Signed-off-by: Jaewon Kim <jaewon02.kim@...sung.com>
> ---
>   drivers/tty/serial/samsung_tty.c | 12 ++++++++++++
>   1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
> index e1585fbae909..8af5aceb9f4e 100644
> --- a/drivers/tty/serial/samsung_tty.c
> +++ b/drivers/tty/serial/samsung_tty.c
> @@ -2480,12 +2480,24 @@ s3c24xx_serial_console_write(struct console *co, const char *s,
>   			     unsigned int count)
>   {
>   	unsigned int ucon = rd_regl(cons_uart, S3C2410_UCON);
> +	unsigned long flags;
> +	bool locked = true;
>   
>   	/* not possible to xmit on unconfigured port */
>   	if (!s3c24xx_port_configured(ucon))
>   		return;
>   
> +	if (cons_uart->sysrq)
> +		locked = false;
> +	else if (oops_in_progress)
> +		locked = spin_trylock_irqsave(&cons_uart->lock, flags);
> +	else
> +		spin_lock_irqsave(&cons_uart->lock, flags);
> +
>   	uart_console_write(cons_uart, s, count, s3c24xx_serial_console_putchar);
> +
> +	if (locked)
> +		spin_unlock_irqrestore(&cons_uart->lock, flags);
>   }
>   
>   /* Shouldn't be __init, as it can be instantiated from other module */


-- 
js
suse labs