linux-kernel - Re: [PATCH resend] fs/proc: Move kfree outside pde_unload

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:	Thu, 4 Apr 2013 21:44:59 +0100
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Nathan Zimmer <nzimmer@....com>
Cc:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	David Woodhouse <dwmw2@...radead.org>, stable@...r.kernel.org
Subject: Re: [PATCH resend] fs/proc: Move kfree outside pde_unload_lock

On Thu, Apr 04, 2013 at 12:12:05PM -0500, Nathan Zimmer wrote:

> Ok I am cloning the tree now.
> It does look like the patches would conflict.
> I'll run some tests and take a deeper look.

FWIW, I've just pushed there a tentative patch that switches to hopefully
saner locking (head should be at cb673c115c1f99d3480471ca5d8cb3f89a1e3bee).
Is that more or less what you want wrt spinlock contention?

One note: for any given pde_opener, close_pdeo() can be called at most
by two threads - final fput() and remove_proc_entry() resp.  I think
the use of completion + flag is safe there; pde->pde_unload_lock
should serialize the critical areas.
--
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/