linux-kernel - Re: [GIT PULL] Please pull NFS client bugfixes....

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 for Android: free password hash cracker in your pocket

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

Message-ID: <1263475127.4244.327.camel@laptop>
Date:	Thu, 14 Jan 2010 14:18:47 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Trond Myklebust <Trond.Myklebust@...app.com>,
	Andi Kleen <andi@...stfloor.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...e.hu>
Subject: Re: [GIT PULL] Please pull NFS client bugfixes....

On Thu, 2010-01-07 at 18:00 -0800, Linus Torvalds wrote:
> 
> On Thu, 7 Jan 2010, Linus Torvalds wrote:
> > 
> > You cannot mmap a directory (and you can't readdir a non-directory), so if 
> > it's a per-inode NFS lock, then the simplest fix _might_ be to just put 
> > directory locks in a different lockdep class from non-directory locks. 
> > That might fix it.
> > 
> > Of course, if it's not a per-inode lock, that doesn't help.
> 
> Hmm. I notice that we already do this in unlock_new_inode() for i_mutex. 
> And I googled for the problem, and it does indeed seem to be about the 
> normal i_mutex <-> mmap_sem thing with filldir-vs-mmap.
> 
> Is there perhaps some path where NFS creates new inodes without going 
> through the normal path? Like the root inode or something? So then you'd 
> have a root inode with i_mutex annotated as being in the same class as a 
> regular file, which completes the lockdep chain.

Quite possible, but I got lost trying to find anything like the root
inode.

> Or maybe there is something else I'm missing.
> 
> I'm adding Peter and Ingo to the Cc as the "lockdep guys". Maybe they see 
> what I am missing.

Not really, nfs_fhget() seems to know about directories as it has a
S_ISDIR() check of itself before doing unlock_new_inode(), so I would
expect unlock_new_inode() to indeed set the
file_system_type::i_mutex_dir_key.



--
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/