linux-kernel - Re: [RFC][PATCH 5/7] tty: Deal with nested sleeps

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, 5 Aug 2014 16:29:16 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	mingo@...nel.org, oleg@...hat.com, torvalds@...ux-foundation.org,
	tglx@...utronix.de, ilya.dryomov@...tank.com,
	umgwanakikbuti@...il.com, linux-kernel@...r.kernel.org,
	Jiri Slaby <jslaby@...e.cz>
Subject: Re: [RFC][PATCH 5/7] tty: Deal with nested sleeps

On Mon, Aug 04, 2014 at 12:30:30PM +0200, Peter Zijlstra wrote:
> n_tty_{read,write} are wait loops with sleeps in. Wait loops rely on
> task_struct::state and sleeps do too, since that's the only means of
> actually sleeping. Therefore the nested sleeps destroy the wait loop
> state and the wait loop breaks the sleep functions that assume
> TASK_RUNNING (mutex_lock).
> 
> Fix this by using the new woken_wake_function and wait_woken() stuff,
> which registers wakeups in wait and thereby allows shrinking the
> task_state::state changes to the actual sleep part.
> 
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Cc: Jiri Slaby <jslaby@...e.cz>
> Signed-off-by: Peter Zijlstra <peterz@...radead.org>
> ---
>  drivers/tty/n_tty.c |   17 +++++------------
>  1 file changed, 5 insertions(+), 12 deletions(-)
> 

Acked-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
--
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/