Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759345Ab3EOPCu (ORCPT ); Wed, 15 May 2013 11:02:50 -0400 Received: from mail-ea0-f178.google.com ([209.85.215.178]:50440 "EHLO mail-ea0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758844Ab3EOPCs (ORCPT ); Wed, 15 May 2013 11:02:48 -0400 Message-ID: <5193A3B5.7010400@suse.cz> Date: Wed, 15 May 2013 17:03:17 +0200 From: Jiri Slaby User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:19.0) Gecko/20130124 Thunderbird/19.0 MIME-Version: 1.0 To: Joerg Roedel , Greg Kroah-Hartman CC: linux-kernel@vger.kernel.org Subject: Re: [PATCH] tty: Add missing lock in n_tty_write() References: <20130515105656.GI24440@8bytes.org> In-Reply-To: <20130515105656.GI24440@8bytes.org> X-Enigmail-Version: 1.6a1pre Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1594 Lines: 53 On 05/15/2013 12:56 PM, Joerg Roedel wrote: > The call of the tty->ops->write callback is protected by > output_lock in all other places I looked at. So it seems the > lock in this code-branch is missing, so take the output_lock > there too. > > Cc: stable@vger.kernel.org > Signed-off-by: Joerg Roedel > --- > drivers/tty/n_tty.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c > index d655416..ffb94a4 100644 > --- a/drivers/tty/n_tty.c > +++ b/drivers/tty/n_tty.c > @@ -2058,10 +2058,14 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, > if (tty->ops->flush_chars) > tty->ops->flush_chars(tty); > } else { > + struct n_tty_data *l = tty->disc_data; > + > + mutex_lock(&l->output_lock); > while (nr > 0) { > c = tty->ops->write(tty, b, nr); > if (c < 0) { > retval = c; > + mutex_unlock(&l->output_lock); > goto break_out; > } > if (!c) > @@ -2069,6 +2073,7 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, > b += c; > nr -= c; > } > + mutex_unlock(&l->output_lock); > } > if (!nr) > break; > Are you fixing any bug here? output_lock does not protect tty->ops->write on the other places, not tty->ops->write. thanks, -- js suse labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/