linux-kernel - Re: [PATCH] idr: Print a stack dump after ida

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Message-ID: <1368437418.4326.3.camel@chaos.site>
Date:	Mon, 13 May 2013 11:30:18 +0200
From:	Jean Delvare <jdelvare@...e.de>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	linux-kernel <linux-kernel@...r.kernel.org>,
	Tejun Heo <tj@...nel.org>, Takashi Iwai <tiwai@...e.de>
Subject: Re: [PATCH] idr: Print a stack dump after ida_remove warning

Hi Andrew,

Le Tuesday 07 May 2013 à 16:34 -0700, Andrew Morton a écrit :
> On Sun, 05 May 2013 11:32:03 +0200 Jean Delvare <jdelvare@...e.de> wrote:
> 
> > We print a dump stack after idr_remove warning. This is useful to find
> > the faulty piece of code. Let's do the same for ida_remove, as it
> > would be equally useful there.
> > 
> > ...
> >
> > --- linux-3.10-rc0.orig/lib/idr.c	2013-05-05 10:17:03.086198024 +0200
> > +++ linux-3.10-rc0/lib/idr.c	2013-05-05 10:41:11.939134735 +0200
> > @@ -1066,6 +1066,7 @@ void ida_remove(struct ida *ida, int id)
> >   err:
> >  	printk(KERN_WARNING
> >  	       "ida_remove called for id=%d which is not allocated.\n", id);
> > +	dump_stack();
> >  }
> >  EXPORT_SYMBOL(ida_remove);
> 
> If we're going to do this, we should make that printk a KERN_EMERG or
> something, otherwise users might see a stack dump with no explanation
> why it occurred.
> 
> We can do all that with plain old WARN().  How does this look?
> 
> 
> From: Andrew Morton <akpm@...ux-foundation.org>
> Subject: idr-print-a-stack-dump-after-ida_remove-warning-fix
> 
> convert the open-coded printk+dump_stack into WARN()
> 
> Cc: Jean Delvare <jdelvare@...e.de>
> Cc: Takashi Iwai <tiwai@...e.de>
> Cc: Tejun Heo <tj@...nel.org>
> Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
> ---
> 
>  lib/idr.c |    8 ++------
>  1 file changed, 2 insertions(+), 6 deletions(-)
> 
> diff -puN lib/idr.c~idr-print-a-stack-dump-after-ida_remove-warning-fix lib/idr.c
> --- a/lib/idr.c~idr-print-a-stack-dump-after-ida_remove-warning-fix
> +++ a/lib/idr.c
> @@ -524,9 +524,7 @@ EXPORT_SYMBOL(idr_alloc_cyclic);
>  
>  static void idr_remove_warning(int id)
>  {
> -	printk(KERN_WARNING
> -		"idr_remove called for id=%d which is not allocated.\n", id);
> -	dump_stack();
> +	WARN(1, "idr_remove called for id=%d which is not allocated.\n", id);
>  }
>  
>  static void sub_remove(struct idr *idp, int shift, int id)
> @@ -1064,9 +1062,7 @@ void ida_remove(struct ida *ida, int id)
>  	return;
>  
>   err:
> -	printk(KERN_WARNING
> -	       "ida_remove called for id=%d which is not allocated.\n", id);
> -	dump_stack();
> +	WARN(1, "ida_remove called for id=%d which is not allocated.\n", id);
>  }
>  EXPORT_SYMBOL(ida_remove);
>  

Acked-by: Jean Delvare <jdelvare@...e.de>

-- 
Jean Delvare
Suse L3

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