linux-kernel - Re: [PATCH 2/2][RFC][BUG] msync: updating ctime and mtime at syncing

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] [thread-next>] [day] [month] [year] [list]

Message-ID: <4df4ef0c0801120438n4a3c1cfpd3563531929a1a91@mail.gmail.com>
Date:	Sat, 12 Jan 2008 15:38:41 +0300
From:	"Anton Salikhmetov" <salikhmetov@...il.com>
To:	"Peter Zijlstra" <a.p.zijlstra@...llo.nl>
Cc:	linux-mm@...ck.org, jakob@...hought.net,
	linux-kernel@...r.kernel.org, Valdis.Kletnieks@...edu,
	riel@...hat.com, ksm@...dk, staubach@...hat.com,
	jesper.juhl@...il.com
Subject: Re: [PATCH 2/2][RFC][BUG] msync: updating ctime and mtime at syncing

2008/1/12, Peter Zijlstra <a.p.zijlstra@...llo.nl>:
>
> On Sat, 2008-01-12 at 10:36 +0100, Peter Zijlstra wrote:
> > On Fri, 2008-01-11 at 03:44 +0300, Anton Salikhmetov wrote:
> >
> > > +/*
> > > + * Update the ctime and mtime stamps after checking if they are to be updated.
> > > + */
> > > +void mapped_file_update_time(struct file *file)
> > > +{
> > > +   if (test_and_clear_bit(AS_MCTIME, &file->f_mapping->flags)) {
> > > +           get_file(file);
> > > +           file_update_time(file);
> > > +           fput(file);
> > > +   }
> > > +}
> > > +
> >
> > I don't think you need the get/put file stuff here, because
>
> BTW, the reason for me noticing this is that if it would be needed there
> is a race condition right there, who is to say that the file pointer
> you're deref'ing in your test condition isn't a dead one already.

So, in your opinion, is it at all needed here to play with the file reference
counter? May I drop the get_file() and fput() calls from the
sys_msync() function?

>
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/