linux-kernel - Re: [REGRESSION 4.13-rc] NFS returns -EACCESS at the first read

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]

Date:   Wed, 26 Jul 2017 09:37:31 -0400
From:   Anna Schumaker <schumaker.anna@...il.com>
To:     Takashi Iwai <tiwai@...e.de>
Cc:     Trond Myklebust <trond.myklebust@...marydata.com>,
        Anna Schumaker <anna.schumaker@...app.com>,
        linux-nfs@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [REGRESSION 4.13-rc] NFS returns -EACCESS at the first read



On 07/26/2017 09:30 AM, Takashi Iwai wrote:
> On Wed, 26 Jul 2017 14:57:07 +0200,
> Anna Schumaker wrote:
>>
>> Hi Takashi,
>>
>> On 07/26/2017 08:54 AM, Takashi Iwai wrote:
>>> Hi,
>>>
>>> I seem hitting a regression of NFS client on the today's Linus git
>>> tree.  The symptom is that the file read over NFS returns occasionally
>>> -EACCESS at the first read.  When I try to read the same file again
>>> (or do some other thing), I can read it successfully.
>>>
>>> The git bisection leaded to the commit
>>> bd8b2441742b49c76bec707757bd9c028ea9838e
>>>     NFS: Store the raw NFS access mask in the inode's access cache
>>>
>>>
>>> Any further hint for debugging?
>>
>> Does the patch in this email thread help? http://www.spinics.net/lists/linux-nfs/msg64930.html
> 
> Thanks, I gave it a shot and the result looks good.  Feel free to my
> tested-by tag:
>   Tested-by: Takashi Iwai <tiwai@...e.de>
> 
> 
> Though, when I look around the code, I feel somehow uneasy by that
> still MAY_XXX is used for nfs_access_entry.mask, e.g. in
> nfs3_proc_access() or nfs4_proc_access().  Are these function OK
> without the similar conversion?

I just started looking at that at the end of the day yesterday.  I think they work by accident, since all the bits in the mask are set by nfs_do_access().  They should probably be converted, but I don't think it's urgent.

Anna

> 
> 
> thanks,
> 
> Takashi
>