tty: n_gsm: Debug output allocation must use GFP_ATOMIC

[PATCH] tty: n_gsm: Debug output allocation must use GFP_ATOMIC

Posted by Tony Lindgren 1 year, 11 months ago

Dan Carpenter <dan.carpenter@oracle.com> reported the following Smatch
warning:

drivers/tty/n_gsm.c:720 gsm_data_kick()
warn: sleeping in atomic context

This is because gsm_control_message() is holding a spin lock so
gsm_hex_dump_bytes() needs to use GFP_ATOMIC instead of GFP_KERNEL.

Fixes: 925ea0fa5277 ("tty: n_gsm: Fix packet data hex dump output")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 drivers/tty/n_gsm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -459,7 +459,7 @@ static void gsm_hex_dump_bytes(const char *fname, const u8 *data,
 		return;
 	}
 
-	prefix = kasprintf(GFP_KERNEL, "%s: ", fname);
+	prefix = kasprintf(GFP_ATOMIC, "%s: ", fname);
 	if (!prefix)
 		return;
 	print_hex_dump(KERN_INFO, prefix, DUMP_PREFIX_OFFSET, 16, 1, data, len,
-- 
2.36.1

Re: [PATCH] tty: n_gsm: Debug output allocation must use GFP_ATOMIC

Posted by Gregory CLEMENT 1 year, 11 months ago

Tony Lindgren <tony@atomide.com> writes:

> Dan Carpenter <dan.carpenter@oracle.com> reported the following Smatch
> warning:
>
> drivers/tty/n_gsm.c:720 gsm_data_kick()
> warn: sleeping in atomic context
>
> This is because gsm_control_message() is holding a spin lock so
> gsm_hex_dump_bytes() needs to use GFP_ATOMIC instead of GFP_KERNEL.
>
> Fixes: 925ea0fa5277 ("tty: n_gsm: Fix packet data hex dump output")
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Tony Lindgren <tony@atomide.com>


Reviewed-by: Gregory CLEMENT <gregory.clement@bootlin.com>


> ---
>  drivers/tty/n_gsm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
> --- a/drivers/tty/n_gsm.c
> +++ b/drivers/tty/n_gsm.c
> @@ -459,7 +459,7 @@ static void gsm_hex_dump_bytes(const char *fname, const u8 *data,
>  		return;
>  	}
>  
> -	prefix = kasprintf(GFP_KERNEL, "%s: ", fname);
> +	prefix = kasprintf(GFP_ATOMIC, "%s: ", fname);
>  	if (!prefix)
>  		return;
>  	print_hex_dump(KERN_INFO, prefix, DUMP_PREFIX_OFFSET, 16, 1, data, len,
> -- 
> 2.36.1

-- 
Gregory Clement, Bootlin
Embedded Linux and Kernel engineering
http://bootlin.com