linux-kernel - Re: nfsd changes for 2.6.37

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: <20101027151959.GA17370@infradead.org>
Date:	Wed, 27 Oct 2010 11:19:59 -0400
From:	Christoph Hellwig <hch@...radead.org>
To:	"J. Bruce Fields" <bfields@...ldses.org>
Cc:	Christoph Hellwig <hch@...radead.org>,
	Arnd Bergmann <arnd@...db.de>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Bryan Schumaker <bjschuma@...app.com>,
	linux-nfs@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: nfsd changes for 2.6.37

On Wed, Oct 27, 2010 at 11:16:46AM -0400, J. Bruce Fields wrote:
> On Wed, Oct 27, 2010 at 10:59:29AM -0400, Christoph Hellwig wrote:
> > On Wed, Oct 27, 2010 at 10:55:39AM -0400, J. Bruce Fields wrote:
> > > Hm, two problems:
> > > 	- We introduce the possibility of fcntl(fd, F_SETLEASE, F_UNLCK)
> > > 	  failing with ENOMEM.
> > 
> > splitt ->setlease into ->add_least and ->delete_lease.  No need to pass
> > in a structure for the later.  No need to return one either.
> 
> Sounds fine to me.
> 
> > 
> > > 	- fasync_helper(.,.,1,.) sleeps.  Argh.
> > 
> > That's not new..
> 
> So we could do
> 
> 	unlock_flocks();
> 	error = fasync_helper(fd, filp, 1, &fl->fl_fasync);
> 	lock_flocks();
> 
> and say, hey, we didn't introduce any new bug there.  But....
> 
> I don't know, maybe add a version of fasync_add_entry() that takes a
> preallocated fasync_struct??

Or just convert the lock to a sleeping mutex.  Now that we have adaptive
spinning the horrible behaviour that Willy saw years ago might not be
that bad any more.  That'll need some benchmarking, though.
--
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/