linux-kernel - Re: [PATCH] ARM: Fix null die() string for unhandled data and prefetch abort cases

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Date:   Sat, 20 Jul 2019 13:30:23 +0100
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     "George G. Davis" <george_davis@...tor.com>
Cc:     "Eric W. Biederman" <ebiederm@...ssion.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Florian Fainelli <f.fainelli@...il.com>,
        Allison Randal <allison@...utok.net>,
        Souptick Joarder <jrdr.linux@...il.com>,
        "moderated list:ARM PORT" <linux-arm-kernel@...ts.infradead.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ARM: Fix null die() string for unhandled data and
 prefetch abort cases

On Fri, Jul 19, 2019 at 10:32:55PM -0400, George G. Davis wrote:
> When an unhandled data or prefetch abort occurs, the die() string
> is empty resulting in backtrace messages similar to the following:
> 
> 	Internal error: : 1 [#1] PREEMPT SMP ARM
> 
> Replace the null string with the name of the abort handler in order
> to provide more meaningful hints as to the cause of the fault.

NAK.

We already print the cause of the abort earlier in the dump, and we've
also added a "cut here" marker to help people include all the necessary
information when reporting a problem.

It's unfortunate that we have the additional colon in the oops dump,
but repeating the information that we've printed on one of the previous
two lines is really not necessary.

> 
> Signed-off-by: George G. Davis <george_davis@...tor.com>
> ---
>  arch/arm/mm/fault.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
> index 0048eadd0681..dddea0a21220 100644
> --- a/arch/arm/mm/fault.c
> +++ b/arch/arm/mm/fault.c
> @@ -557,7 +557,7 @@ do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
>  		inf->name, fsr, addr);
>  	show_pte(current->mm, addr);
>  
> -	arm_notify_die("", regs, inf->sig, inf->code, (void __user *)addr,
> +	arm_notify_die(inf->name, regs, inf->sig, inf->code, (void __user *)addr,
>  		       fsr, 0);
>  }
>  
> @@ -585,7 +585,7 @@ do_PrefetchAbort(unsigned long addr, unsigned int ifsr, struct pt_regs *regs)
>  	pr_alert("Unhandled prefetch abort: %s (0x%03x) at 0x%08lx\n",
>  		inf->name, ifsr, addr);
>  
> -	arm_notify_die("", regs, inf->sig, inf->code, (void __user *)addr,
> +	arm_notify_die(inf->name, regs, inf->sig, inf->code, (void __user *)addr,
>  		       ifsr, 0);
>  }
>  
> -- 
> 2.7.4
> 
> 

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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