linux-kernel - Re: [PATCH 2/4] staging: most: Replace calls to BUG_ON() with WARN

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Message-ID: <20180301162130.GB15087@kroah.com>
Date:   Thu, 1 Mar 2018 17:21:30 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Quytelda Kahja <quytelda@...alin.org>
Cc:     christian.gromm@...rochip.com, devel@...verdev.osuosl.org,
        Michael.Fabry@...rochip.com, chris@...ineersdelight.de,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/4] staging: most: Replace calls to BUG_ON() with
 WARN_ONCE() and return.

On Fri, Feb 23, 2018 at 11:58:33PM -0800, Quytelda Kahja wrote:
> Replace calls to BUG_ON() used to check for NULL pointers with WARN_ONCE()
> followed by a return.

Are you sure this will work?

> 
> Signed-off-by: Quytelda Kahja <quytelda@...alin.org>
> ---
>  drivers/staging/most/core.c | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/staging/most/core.c b/drivers/staging/most/core.c
> index 18157dd80324..3f65390a6e17 100644
> --- a/drivers/staging/most/core.c
> +++ b/drivers/staging/most/core.c
> @@ -916,7 +916,11 @@ static void arm_mbo(struct mbo *mbo)
>  	unsigned long flags;
>  	struct most_channel *c;
>  
> -	BUG_ON((!mbo) || (!mbo->context));
> +	if (WARN_ONCE(!mbo || !mbo->context,
> +		      "Bad mbo or missing channel reference.\n")) {
> +		return;

How is the code supposed to recover from this major problem?

> +	}
> +
>  	c = mbo->context;
>  
>  	if (c->is_poisoned) {
> @@ -1001,7 +1005,7 @@ static int arm_mbo_chain(struct most_channel *c, int dir,
>  void most_submit_mbo(struct mbo *mbo)
>  {
>  	if (WARN_ONCE(!mbo || !mbo->context,
> -		      "bad mbo or missing channel reference\n"))
> +		      "Bad mbo or missing channel reference.\n"))

You did something different here that you did not describe in your
changelog :(

thanks,

greg k-h