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From: Jan Glauber <Jan.Glauber@cavium.com>
To: Will Deacon <will.deacon@arm.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: dcache_readdir NULL inode oops
Date: Sat, 10 Nov 2018 11:17:03 +0000	[thread overview]
Message-ID: <20181110111656.GA16667@hc> (raw)
In-Reply-To: <20181109155856.GC2091@brain-police>

On Fri, Nov 09, 2018 at 03:58:56PM +0000, Will Deacon wrote:
> On Fri, Nov 09, 2018 at 02:37:51PM +0000, Jan Glauber wrote:
> > I'm seeing the following oops reproducible with upstream kernel on arm64
> > (ThunderX2):
> 
> [...]
> 
> > It happens after 1-3 hours of running 'stress-ng --dev 128'. This testcase
> > does a scandir of /dev and then calls random stuff like ioctl, lseek,
> > open/close etc. on the entries. I assume no files are deleted under /dev
> > during the testcase.
> >
> > The NULL pointer is the inode pointer of next. The next dentry->d_flags is
> > DCACHE_RCUACCESS when this happens.
> >
> > Any hints on how to further debug this?
> 
> Can you reproduce the issue with vanilla -rc1 and do you have a "known good"
> kernel?

I can try out -rc1, but IIRC this wasn't bisectible as the bug was present at
least back to 4.14. I need to double check that as there were other issues
that are resolved now so I may confuse things here. I've defintely seen
the same bug with 4.18.

Unfortunately I lost access to the machine as our data center seems to be
moving currently so it might take some days until I can try -rc1.

thanks,
Jan

  reply	other threads:[~2018-11-10 21:01 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-09 14:37 dcache_readdir NULL inode oops Jan Glauber
2018-11-09 15:58 ` Will Deacon
2018-11-10 11:17   ` Jan Glauber [this message]
2018-11-20 18:28     ` Will Deacon
2018-11-20 19:03       ` Will Deacon
2018-11-21 13:19         ` Jan Glauber
2018-11-23 18:05           ` Will Deacon
2018-11-28 20:08             ` Will Deacon
2018-11-29 19:25               ` Jan Glauber
2018-11-30 10:41                 ` gregkh
2018-11-30 15:16                   ` Eric W. Biederman
2018-11-30 16:08                     ` Al Viro
2018-11-30 16:32                       ` Will Deacon
2019-04-30  9:32                         ` Jan Glauber

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