linux-kernel - Re: [patch 7/9] signals: Fix more rcu assumptions

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:	Fri, 11 Dec 2009 13:59:04 +0000
From:	David Howells <dhowells@...hat.com>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	dhowells@...hat.com, Oleg Nesterov <oleg@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Dipankar Sarma <dipankar@...ibm.com>,
	Ingo Molnar <mingo@...e.hu>,
	Peter Zijlstra <peterz@...radead.org>,
	Al Viro <viro@...iv.linux.org.uk>,
	James Morris <jmorris@...ei.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [patch 7/9] signals: Fix more rcu assumptions

Thomas Gleixner <tglx@...utronix.de> wrote:

> > Perhaps it is better to modify __sigqueue_alloc() instead? It can take
> > rcu_lock() around cred->user itself.
> 
> Indeed. Was too tired to see the obvious :)

Ah, but...  If __sigqueue_alloc() is called from sigqueue_alloc(), then you
don't need the RCU read lock as the target task is current.

So perhaps the callsite for __sigqueue_alloc() in __send_signal()?  That at
least puts the rcu_read_lock() call in proximity to the function that actually
needs it.

David
--
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/