From: Jan Kara <jack@suse.cz>
To: Amir Goldstein <amir73il@gmail.com>
Cc: Jan Kara <jack@suse.cz>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Greg KH <gregkh@linuxfoundation.org>
Subject: Re: [PATCH 2/2] fsnotify: Protect bail out path of fsnotify_add_mark_locked() properly
Date: Tue, 31 Oct 2017 17:10:08 +0100 [thread overview]
Message-ID: <20171031161008.GD26128@quack2.suse.cz> (raw)
In-Reply-To: <CAOQ4uxihykkEa87Q1W6mO80M0YY4adNyeOmSpx29X9Pi2VA1HQ@mail.gmail.com>
On Tue 31-10-17 14:26:35, Amir Goldstein wrote:
> On Tue, Oct 31, 2017 at 11:33 AM, Jan Kara <jack@suse.cz> wrote:
> > When fsnotify_add_mark_locked() fails it cleans up the mark it was
> > adding. Since the mark is already visible in group's list, we should
> > protect update of mark->flags with mark->lock. I'm not aware of any real
> > issues this could cause (since we also hold group->mark_mutex) but
> > better be safe and obey locking rules properly.
> >
> > Signed-off-by: Jan Kara <jack@suse.cz>
>
> Reviewed-by: Amir Goldstein <amir73il@gmail.com>
>
> IMO, even though this does not fix a concrete bug, if it's worth
> fixing in upstream, it's worth fixing in stable.
> A future stable fix may either make this into a concrete bug
> or just be harder to apply.
>
> So I suggest to add the Fixes: and Cc: stable tags.
>
> Greg,
>
> Do you agree with this reasoning?
Similarly as with patch 1, I don't think real users can hit this (and even
if they could, I doubt it would have any negative impact). So bothering
stable with this is just a waste of resources... It falls under the
"theoretical race condition" cathegory which is explicitely forbidden from
stable.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
prev parent reply other threads:[~2017-10-31 16:10 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-31 9:33 [PATCH 0/2] dnotify: Fix ENOMEM handling Jan Kara
2017-10-31 9:33 ` [PATCH 1/2] dnotify: Handle errors from fsnotify_add_mark_locked() in fcntl_dirnotify() Jan Kara
2017-10-31 12:11 ` Amir Goldstein
2017-10-31 15:45 ` Jan Kara
2017-10-31 16:15 ` Jan Kara
2017-10-31 16:28 ` Amir Goldstein
2017-10-31 9:33 ` [PATCH 2/2] fsnotify: Protect bail out path of fsnotify_add_mark_locked() properly Jan Kara
2017-10-31 12:26 ` Amir Goldstein
2017-10-31 12:50 ` Greg KH
2017-10-31 12:57 ` Amir Goldstein
2017-10-31 13:40 ` Greg KH
2017-10-31 16:10 ` Jan Kara [this message]
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