linux-kernel - Re: [announce] vfs-scale git tree update

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]

Date:	Tue, 11 Jan 2011 08:51:42 -0800
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	aelder@....com
Cc:	Nick Piggin <npiggin@...nel.dk>, Al Viro <viro@...iv.linux.org.uk>,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [announce] vfs-scale git tree update

On Tue, Jan 11, 2011 at 8:34 AM, Alex Elder <aelder@....com> wrote:
>
> FYI, when using this code, as merged by Linus, I hit the
> BUG_ON() at the beginning of d_set_d_op() when it's called
> by autofs4_dir_mkdir().  I managed to work around it by
> just commenting out those BUG_ON() calls but it's something
> that ought to get addressed properly.

Yeah, removing the BUG_ON() isn't the right thing to do - it means
that autofs4 is obviously setting the dentry ops twice for the same
dentry.

Possibly the thing could be relaxed to allow setting the _same_ d_op
pointer, ie do something like

   if (dentry->d_op == op)
      return;

at the top of that function. But looking at it, I don't think that
fixes the autofs4 issue.

The fact that autofs4 does "d_add()" before it sets the d_ops (or
other dentry state, for that matter) looks a bit scary. To me that
smells like it might get a  dentry lookup hit before it's actually
fully done.

Does it make any difference if you move the various d_add() calls down
to the end of the functions to when the "dentry" has really been
instantiated?

                      Linus
--
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/