Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932352AbWBUU2a (ORCPT ); Tue, 21 Feb 2006 15:28:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932553AbWBUU2a (ORCPT ); Tue, 21 Feb 2006 15:28:30 -0500 Received: from mx1.redhat.com ([66.187.233.31]:52621 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S932352AbWBUU23 (ORCPT ); Tue, 21 Feb 2006 15:28:29 -0500 Date: Tue, 21 Feb 2006 15:27:57 -0500 From: Dave Jones To: "David S. Miller" Cc: ak@suse.de, linux-kernel@vger.kernel.org, mingo@elte.hu Subject: Re: softlockup interaction with slow consoles Message-ID: <20060221202757.GB24159@redhat.com> Mail-Followup-To: Dave Jones , "David S. Miller" , ak@suse.de, linux-kernel@vger.kernel.org, mingo@elte.hu References: <20060221.120143.15763934.davem@davemloft.net> <200602212105.38075.ak@suse.de> <20060221.121948.60060362.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060221.121948.60060362.davem@davemloft.net> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3032 Lines: 70 On Tue, Feb 21, 2006 at 12:19:48PM -0800, David S. Miller wrote: > From: Andi Kleen > Date: Tue, 21 Feb 2006 21:05:37 +0100 > > > The classic way is to just use touch_nmi_watchdog() somewhere > > in the loop that does work. That touches the softwatchdog too > > these days. > > "jiffies" aren't advancing, since interrupts are disabled by > release_console_sem(), so that doesn't work. > > I tried that already :-) Where did you put it? I hit a similar problem a few months back, and this patch did the trick for me.. Dave NMI Watchdog detected LOCKUP on CPU2CPU 2 Modules linked in: loop usb_storage md5 ipv6 parport_pc lp parport autofs4 i2c_dev i2c_core rfcomm l2cap bluetooth sunrpc pcdPid: 3138, comm: gpm Not tainted 2.6.11-1.1290_FC4smp RIP: 0010:[] {serial_in+106} RSP: 0018:ffff81003afc3d50 EFLAGS: 00000002 RAX: 0000000000000020 RBX: 0000000000000020 RCX: 0000000000000000 RDX: 00000000000003fd RSI: 0000000000000005 RDI: ffffffff804dcd60 RBP: 00000000000024fc R08: 000000000000000a R09: 0000000000000033 R10: ffff81001beb7c20 R11: 0000000000000020 R12: ffffffff804dcd60 R13: ffffffff804ade76 R14: 000000000000002b R15: 000000000000002c FS: 00002aaaaaac4920(0000) GS:ffffffff804fca00(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00002aaaaabcb000 CR3: 000000003c0d0000 CR4: 00000000000006e0 Process gpm (pid: 3138, threadinfo ffff81003afc2000, task ffff81003eb63780) Stack: ffffffff80275f2e 0000000000000000 ffffffff80448380 0000000000007d6b 000000000000002c fffffffffffffbbf 0000000000000292 0000000000008000 ffffffff80138e8c 0000000000007d97 Call Trace:{serial8250_console_write+270} {__call_console_drivers+76} {release_console_sem+315} {con_open+149} {tty_open+537} {chrdev_open+387} {dentry_open+260} {filp_open+68} {get_unused_fd+227} {sys_open+76} {tracesys+209} Code: 0f b6 c0 c3 66 90 41 57 49 89 f7 41 56 41 be 00 01 00 00 41 console shuts up ... --- linux-2.6.11/drivers/serial/8250.c~ 2005-05-14 02:49:02.000000000 -0400 +++ linux-2.6.11/drivers/serial/8250.c 2005-05-14 02:54:30.000000000 -0400 @@ -2098,9 +2098,11 @@ static inline void wait_for_xmitr(struct /* Wait up to 1s for flow control if necessary */ if (up->port.flags & UPF_CONS_FLOW) { tmout = 1000000; - while (--tmout && - ((serial_in(up, UART_MSR) & UART_MSR_CTS) == 0)) + while (!(serial_in(up, UART_MSR) & UART_MSR_CTS) && --tmout) { udelay(1); + if ((tmout % 1000) == 0) + touch_nmi_watchdog(); + } } } - 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/