linux-kernel - Re: [PATCH 1/2] vfs: free vfsmount through rcu work from kern

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: <YhCG9cdw2JZSKbDZ@zeniv-ca.linux.org.uk>
Date:   Sat, 19 Feb 2022 05:58:13 +0000
From:   Al Viro <viro@...iv.linux.org.uk>
To:     Rik van Riel <riel@...riel.com>
Cc:     linux-kernel@...r.kernel.org, kernel-team@...com,
        linux-fsdevel@...r.kernel.org, paulmck@...nel.org,
        gscrivan@...hat.com, Eric Biederman <ebiederm@...ssion.com>,
        Chris Mason <clm@...com>
Subject: Re: [PATCH 1/2] vfs: free vfsmount through rcu work from kern_unmount

On Sat, Feb 19, 2022 at 05:53:37AM +0000, Al Viro wrote:
> On Fri, Feb 18, 2022 at 01:31:13PM -0500, Rik van Riel wrote:
> 
> >  struct super_block;
> >  struct vfsmount;
> > @@ -73,6 +74,7 @@ struct vfsmount {
> >  	struct super_block *mnt_sb;	/* pointer to superblock */
> >  	int mnt_flags;
> >  	struct user_namespace *mnt_userns;
> > +	struct rcu_work free_rwork;
> >  } __randomize_layout;
> 
> Wait, what?  First of all, that has no business being in vfsmount -
> everything that deeply internal belongs in struct mount, not in
> its public part.  Moreover, there's already mount->mnt_rcu, so what's
> the point duplicating that?

Argh... You need rcu_work there...

OK, so make that a member of the same union mnt_rcu is.  In struct mount,
please.  And I'm not sure I like the idea of shoving that much into
struct mount, TBH...