diff mbox series

[2/2] drivers: tty: vt: vt.c: fixed segmentation fault in vt.c

Message ID 20231101235332.4314-1-dimadrumspro@gmail.com
State Superseded
Headers show
Series None | expand

Commit Message

dimadrumspro@gmail.com Nov. 1, 2023, 11:53 p.m. UTC
From: dimaaac <dimadrumspro@gmail.com>

The previous code lacked proper synchronization, leading to potential data corruption and crashes. Added a spin lock to protect shared variable 'scrollback_delta' to prevent concurrent access.

Signed-off-by: dimaaac <dimaac@bk.ru>
---
 drivers/tty/vt/vt.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

Comments

Greg Kroah-Hartman Nov. 2, 2023, 5:45 a.m. UTC | #1
On Thu, Nov 02, 2023 at 12:53:32AM +0100, dimadrumspro@gmail.com wrote:
> From: dimaaac <dimadrumspro@gmail.com>
> 
> The previous code lacked proper synchronization, leading to potential data corruption and crashes. Added a spin lock to protect shared variable 'scrollback_delta' to prevent concurrent access.
> 
> Signed-off-by: dimaaac <dimaac@bk.ru>
> ---
>  drivers/tty/vt/vt.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
> index 5c47f77804f0..29cf7fe11662 100644
> --- a/drivers/tty/vt/vt.c
> +++ b/drivers/tty/vt/vt.c
> @@ -301,12 +301,13 @@ static inline unsigned short *screenpos(const struct vc_data *vc, int offset,
>  }
>  
>  /* Called  from the keyboard irq path.. */
> +static DEFINE_SPINLOCK(scrolldelta_lock);
> +
>  static inline void scrolldelta(int lines)
>  {
> -	/* FIXME */
> -	/* scrolldelta needs some kind of consistency lock, but the BKL was
> -	   and still is not protecting versus the scheduled back end */
> +	spin_lock(&scrolldelta_lock);
>  	scrollback_delta += lines;
> +	spin_unlock(&scrolldelta_lock);
>  	schedule_console_callback();
>  }
>  
> -- 
> 2.42.0
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
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diff mbox series

Patch

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 5c47f77804f0..29cf7fe11662 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -301,12 +301,13 @@  static inline unsigned short *screenpos(const struct vc_data *vc, int offset,
 }
 
 /* Called  from the keyboard irq path.. */
+static DEFINE_SPINLOCK(scrolldelta_lock);
+
 static inline void scrolldelta(int lines)
 {
-	/* FIXME */
-	/* scrolldelta needs some kind of consistency lock, but the BKL was
-	   and still is not protecting versus the scheduled back end */
+	spin_lock(&scrolldelta_lock);
 	scrollback_delta += lines;
+	spin_unlock(&scrolldelta_lock);
 	schedule_console_callback();
 }