Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755049AbXLSQKi (ORCPT ); Wed, 19 Dec 2007 11:10:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752773AbXLSQKW (ORCPT ); Wed, 19 Dec 2007 11:10:22 -0500 Received: from nat-132.atmel.no ([80.232.32.132]:56737 "EHLO relay.atmel.no" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752689AbXLSQKU (ORCPT ); Wed, 19 Dec 2007 11:10:20 -0500 Date: Wed, 19 Dec 2007 17:09:35 +0100 From: Haavard Skinnemoen To: "Remy Bohmer" Cc: "Andrew Victor" , linux-arm-kernel@lists.arm.linux.org.uk, "Russell King" , linux-kernel@vger.kernel.org, kernel@avr32linux.org Subject: Re: [PATCH v2 0/6] atmel_serial: Cleanups, irq handler splitup & DMA Message-ID: <20071219170935.4df62471@dhcp-252-066.norway.atmel.com> In-Reply-To: <3efb10970712190757m18f8851cq54061ff109790805@mail.gmail.com> References: <1198077130-9021-1-git-send-email-hskinnemoen@atmel.com> <3efb10970712190757m18f8851cq54061ff109790805@mail.gmail.com> Organization: Atmel Norway X-Mailer: Claws Mail 3.1.0 (GTK+ 2.12.1; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1336 Lines: 40 On Wed, 19 Dec 2007 16:57:04 +0100 "Remy Bohmer" wrote: > Hello Haavard, > > Sorry.. But I get an Oops on Preempt-RT with the latest set of > patches. I did not see it earlier today with the other set of patches. Hmm...from the backtrace, it looks like lock recursion -- port->lock is held for the whole duration of the tasklet, but we somehow end up in uart_start(), which grabs the lock again. Could you try the patch below? It's a bit strange that you got an oops though... Haavard diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c index 7967054..948c643 100644 --- a/drivers/serial/atmel_serial.c +++ b/drivers/serial/atmel_serial.c @@ -666,7 +666,13 @@ static void atmel_rx_from_ring(struct uart_port *port) uart_insert_char(port, status, ATMEL_US_OVRE, c.ch, flg); } + /* + * Drop the lock here since it might end up calling + * uart_start(), which takes the lock. + */ + spin_unlock(&port->lock); tty_flip_buffer_push(port->info->tty); + spin_lock(&port->lock); } static void atmel_rx_from_dma(struct uart_port *port) -- 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/