From: Al Viro <viro@ZenIV.linux.org.uk>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "'tj@kernel.org'" <tj@kernel.org>,
"Hatayama, Daisuke" <d.hatayama@jp.fujitsu.com>,
"'gregkh@linuxfoundation.org'" <gregkh@linuxfoundation.org>,
"Okajima, Toshiyuki" <toshi.okajima@jp.fujitsu.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"'ebiederm@aristanetworks.com'" <ebiederm@aristanetworks.com>
Subject: Re: [CFT][PATCH] kernfs: Correct kernfs directory seeks.
Date: Thu, 7 Jun 2018 19:36:20 +0100 [thread overview]
Message-ID: <20180607183620.GU30522@ZenIV.linux.org.uk> (raw)
In-Reply-To: <8736y1dt1m.fsf@xmission.com>
On Tue, Jun 05, 2018 at 12:47:33PM -0500, Eric W. Biederman wrote:
> Sigh, I have found another issue with kernfs_fop_readdir.
>
> We are not currently protecting file->private_data with the kernfs_mutex
> or any other kind of serialization. Which means if two processes are
> calling readdir on the same file descriptor we might get unpredictable
> behavior.
>
> It doesn't look too bad and easy enough to fix, but definitely something
> to be watchful of.
As discussed off-list - this is not a problem; getdents() et.al. are
serialized on per-struct-file basis by fdget_pos() in relevant syscalls,
since all directories automatically get FMODE_ATOMIC_POS in ->f_mode.
prev parent reply other threads:[~2018-06-07 18:36 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-28 12:54 [RESEND PATCH v2] kernfs: fix dentry unexpected skip Hatayama, Daisuke
2018-05-28 13:08 ` Hatayama, Daisuke
2018-05-29 16:26 ` 'tj@kernel.org'
2018-06-01 9:25 ` Hatayama, Daisuke
2018-06-01 17:07 ` 'tj@kernel.org'
2018-06-04 9:46 ` Hatayama, Daisuke
2018-06-02 17:25 ` Eric W. Biederman
2018-06-03 18:51 ` [CFT][PATCH] kernfs: Correct kernfs directory seeks Eric W. Biederman
2018-06-04 9:34 ` Hatayama, Daisuke
2018-06-04 14:44 ` Eric W. Biederman
2018-06-05 2:02 ` Eric W. Biederman
2018-06-05 5:52 ` Hatayama, Daisuke
2018-06-05 5:45 ` Hatayama, Daisuke
2018-06-05 15:31 ` Eric W. Biederman
2018-06-05 15:42 ` 'tj@kernel.org'
2018-06-05 17:47 ` Eric W. Biederman
2018-06-07 18:36 ` Al Viro [this message]
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