From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
To: sedat.dilek@gmail.com
Cc: linux-next@vger.kernel.org, linux-kernel@vger.kernel.org,
Al Viro <viro@zeniv.linux.org.uk>, Jens Axboe <axboe@kernel.dk>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Miklos Szeredi <miklos@szeredi.hu>,
fuse-devel@lists.sourceforge.net,
Stephen Rothwell <sfr@canb.auug.org.au>,
Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: linux-next: Tree for Jun 26 [ vfs | block | fuse (cpuidle) releated? ]
Date: Wed, 26 Jun 2013 17:24:46 +0200 [thread overview]
Message-ID: <20130626172446.51f0bd5f@skate> (raw)
In-Reply-To: <CA+icZUXtTxVUfOmFak9GzyUdGa7bBuxTr2CJEY0vNn0bH2-4Vw@mail.gmail.com>
Dear Sedat Dilek,
On Wed, 26 Jun 2013 16:50:55 +0200, Sedat Dilek wrote:
> [ TO/CC char-misc folks ]
>
> The CULPRIT commit [1] due to my git-bisecting is:
>
> commit 585d98e00ba7a5e2abe65f7a1eff631cb612289b
> "char: misc: assign file->private_data in all cases"
>
> After reverting it, my system boots up fine again.
>
> Can someone from the char-misc folks look at that?
Ok. My understanding is that the misc device registered by
fs/fuse/dev.c:fuse_dev_init() makes the assumption that
file->private_data == NULL when a misc device is opened. But I'm not
sure to fully understand the code flow of the FUSE filesystem.
And since it doesn't provide its own implementation of the ->open()
operation, the misc infrastructure was leaving the file->private_data
defined to NULL before my patch.
With my patch, the file->private_data gets assigned unconditionally
(regardless of whether the misc driver provides or does not provide a
->open() operation) which modifies the unwritten assumption that fuse
was making about the initial value of file->private_data. I believe the
assumption made by fuse over the initial value of this variable is a
bit fragile.
Maybe the FUSE code needs to be slightly adjusted to not make this
assumption?
Best regards,
Thomas
--
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
next prev parent reply other threads:[~2013-06-26 15:24 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-26 9:48 linux-next: Tree for Jun 26 [ vfs | block | fuse (cpuidle) releated? ] Sedat Dilek
2013-06-26 9:50 ` Sedat Dilek
2013-06-26 14:50 ` Sedat Dilek
2013-06-26 15:24 ` Thomas Petazzoni [this message]
2013-06-26 15:31 ` Sedat Dilek
2013-06-26 15:32 ` Greg Kroah-Hartman
2013-06-26 15:36 ` Sedat Dilek
2013-06-26 17:15 ` Greg Kroah-Hartman
2013-06-26 17:47 ` Sedat Dilek
2013-06-26 15:46 ` Thomas Petazzoni
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