linux-kernel - Re: [PATCH] x86: fix IO APIC resource allocation error message

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Date:	Fri, 20 Mar 2009 23:09:54 +0300
From:	Cyrill Gorcunov <gorcunov@...il.com>
To:	Bartlomiej Zolnierkiewicz <bzolnier@...il.com>
Cc:	Ingo Molnar <mingo@...e.hu>,
	Alan Bartlett <ajb.stxsl@...glemail.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86: fix IO APIC resource allocation error message

[Bartlomiej Zolnierkiewicz - Fri, Mar 20, 2009 at 09:02:28PM +0100]
| On Friday 20 March 2009, Cyrill Gorcunov wrote:
| > [Bartlomiej Zolnierkiewicz - Fri, Mar 20, 2009 at 08:12:41PM +0100]
| > | From: Bartlomiej Zolnierkiewicz <bzolnier@...il.com>
| > | Subject: [PATCH] x86: fix IO APIC resource allocation error message
| > | 
| > | Impact: fix incorrect error message
| > | 
| > | - IO APIC resource allocation error message contains one too many "be".
| > | 
| > | - Print the error message iff there are IO APICs in the system.
| > | 
| > | Cc: Alan Bartlett <ajb.stxsl@...glemail.com>
| > | Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@...il.com>
| > | ---
| > | I've seen this error message for some time on my x86-32 laptop...
| > | 
| > |  arch/x86/kernel/io_apic.c |    4 ++--
| > |  1 file changed, 2 insertions(+), 2 deletions(-)
| > | 
| > | Index: b/arch/x86/kernel/io_apic.c
| > | ===================================================================
| > | --- a/arch/x86/kernel/io_apic.c
| > | +++ b/arch/x86/kernel/io_apic.c
| > | @@ -4150,9 +4150,9 @@ static int __init ioapic_insert_resource
| > |  	int i;
| > |  	struct resource *r = ioapic_resources;
| > |  
| > | -	if (!r) {
| > | +	if (!r && nr_ioapics > 0) {
| > |  		printk(KERN_ERR
| > | -		       "IO APIC resources could be not be allocated.\n");
| > | +		       "IO APIC resources couldn't be allocated.\n");
| > |  		return -1;
| > |  	}
| > |  
| > | 
| > 
| > Hi Bartlomiej,
| > 
| > until I miss something I guess you could even make it simplier :)
| > Something like
| > 
| > ---
| > static int __init ioapic_insert_resources(void)
| > {
| > 	struct resource *r = ioapic_resources;
| > 	int err;
| > 	int i;
| > 
| > 	for (i = 0; i < nr_ioapics; i++) {
| > 		err = insert_resource(&iomem_resource, r);
| > 		if (err) {
| > 			pr_err("IO APIC resources could not be allocated.\n");
| > 			return err;
| > 		}
| > 		r++;
| > 	}
| > 
| > 	return 0;
| > }
| > ---
| > 
| > Now we would have 'err' here and get out only on conflicting resource.
| > Did I miss something?
| 
| nr_ioapics > 0 && r == NULL ?
| 

This case happens when alloc_bootmem fails but we already panic'ed!

Here is what I mean

>From ioapic_setup_resources()

	if (nr_ioapics <= 0)
		return NULL;

	mem = alloc_bootmem(n); <- we panic here anyway
	...
	ioapic_resources = res;

	- Cyrill -
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