linux-kernel - Re: [PATCH 1/2] xen: correct error handling in xen-acpi-processor

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <5ca1a49b-da31-d1cc-46e3-6ff92d9f0833@suse.com>
Date:   Fri, 31 Mar 2017 16:19:28 +0200
From:   Juergen Gross <jgross@...e.com>
To:     Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org
Cc:     konrad.wilk@...cle.com, stable@...r.kernel.org
Subject: Re: [PATCH 1/2] xen: correct error handling in xen-acpi-processor

On 31/03/17 16:10, Boris Ostrovsky wrote:
> On 03/31/2017 07:19 AM, Juergen Gross wrote:
>> Error handling in upload_pm_data() is rather questionable: possible
>> errno values from called functions are or'ed together resulting in
>> strange return values: -EINVAL and -ENOMEM would e.g. result in
>> returning -EXDEV.
> 
> And it doesn't matter anyway since noone checks return value. (not that
> OR-ing errors makes much sense)

Ha, you are right!

So I can just fold the patches into one and turn some more functions
into retuning void.


Juergen

> 
>>
>> Fix this by bailing out early after the first error.
> 
> I am not sure about this: why should we not try to load P states if C
> states failed to load?
> 
> -boris
> 
>>
>> Cc: stable@...r.kernel.org
>> Signed-off-by: Juergen Gross <jgross@...e.com>
>> ---
>>  drivers/xen/xen-acpi-processor.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/xen/xen-acpi-processor.c b/drivers/xen/xen-acpi-processor.c
>> index 23e391d..3659ed3 100644
>> --- a/drivers/xen/xen-acpi-processor.c
>> +++ b/drivers/xen/xen-acpi-processor.c
>> @@ -283,8 +283,8 @@ static int upload_pm_data(struct acpi_processor *_pr)
>>  	if (_pr->flags.power)
>>  		err = push_cxx_to_hypervisor(_pr);
>>  
>> -	if (_pr->performance && _pr->performance->states)
>> -		err |= push_pxx_to_hypervisor(_pr);
>> +	if (!err && _pr->performance && _pr->performance->states)
>> +		err = push_pxx_to_hypervisor(_pr);
>>  
>>  	mutex_unlock(&acpi_ids_mutex);
>>  	return err;
> 
>