From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758776Ab3BFV7Y (ORCPT ); Wed, 6 Feb 2013 16:59:24 -0500 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:20808 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758615Ab3BFV7Q (ORCPT ); Wed, 6 Feb 2013 16:59:16 -0500 X-Authority-Analysis: v=2.0 cv=f8jK9ZOM c=1 sm=0 a=rXTBtCOcEpjy1lPqhTCpEQ==:17 a=mNMOxpOpBa8A:10 a=Ciwy3NGCPMMA:10 a=iX436ahayn8A:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=meVymXHHAAAA:8 a=Kq2jaWyG-zMA:10 a=VwQbUJbxAAAA:8 a=5GsgiXXBMyPZXWBjK_kA:9 a=Zh68SRI7RUMA:10 a=jeBq3FmKZ4MA:10 a=rXTBtCOcEpjy1lPqhTCpEQ==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 74.67.115.198 Message-Id: <20130206215915.058901172@goodmis.org> User-Agent: quilt/0.60-1 Date: Wed, 06 Feb 2013 16:58:19 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-rt-users Cc: Thomas Gleixner , Carsten Emde , John Kacur , Subject: [PATCH RT 1/6] drivers-tty-pl011-irq-disable-madness.patch References: <20130206215818.969089606@goodmis.org> Content-Disposition: inline; filename=0001-drivers-tty-pl011-irq-disable-madness.patch.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Gleixner Cc: stable-rt@vger.kernel.org Signed-off-by: Thomas Gleixner Signed-off-by: Steven Rostedt --- drivers/tty/serial/amba-pl011.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index b69356c..7b29c92 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -1788,13 +1788,19 @@ pl011_console_write(struct console *co, const char *s, unsigned int count) clk_enable(uap->clk); - local_irq_save(flags); + /* + * local_irq_save(flags); + * + * This local_irq_save() is nonsense. If we come in via sysrq + * handling then interrupts are already disabled. Aside of + * that the port.sysrq check is racy on SMP regardless. + */ if (uap->port.sysrq) locked = 0; else if (oops_in_progress) - locked = spin_trylock(&uap->port.lock); + locked = spin_trylock_irqsave(&uap->port.lock, flags); else - spin_lock(&uap->port.lock); + spin_lock_irqsave(&uap->port.lock, flags); /* * First save the CR then disable the interrupts @@ -1816,8 +1822,7 @@ pl011_console_write(struct console *co, const char *s, unsigned int count) writew(old_cr, uap->port.membase + UART011_CR); if (locked) - spin_unlock(&uap->port.lock); - local_irq_restore(flags); + spin_unlock_irqrestore(&uap->port.lock, flags); clk_disable(uap->clk); } -- 1.7.10.4