linux-kernel - Re: [PATCH] tty: add lockdep annotations

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:	Sat, 2 Jun 2012 21:19:17 +0100
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Eric Dumazet <eric.dumazet@...il.com>,
	Alan Cox <alan@...ux.intel.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Jens Axboe <jaxboe@...ionio.com>
Subject: Re: [PATCH] tty: add lockdep annotations

> I *think* this makes sense. But it has has had absolutely zero
> testing. It compiles in my config, and the locking is at least
> sensible and well-localized, but maybe I'm missing something.
> 
> Comments?

Yep. Been that way 8)

tty_driver_remove_tty is called from tty_shutdown is called from the
final tty_kref_put can be called from IRQ context.

If you move the tty_driver_remove_tty into the queued part of the code
path then driver->termios[] races appear between the destructor and the
next allocation of the same tty.

Really tty_driver_remove_tty should occur at the end of tty_release, and
tty->termios should simply be a struct ktermios (its a fairly small
structure) and copied back to the drivers array on drivers that need it.
That cleans up pty as well.

Alan
--
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/