From mboxrd@z Thu Jan 1 00:00:00 1970 From: u.kleine-koenig@pengutronix.de (Uwe =?iso-8859-1?Q?Kleine-K=F6nig?=) Date: Thu, 2 Aug 2012 10:34:13 +0200 Subject: How to debug hard lockup issue In-Reply-To: References: <20120802071530.GG10670@pengutronix.de> Message-ID: <20120802083413.GH10670@pengutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Aug 02, 2012 at 03:59:36PM +0800, Lin Ming wrote: > On Thu, Aug 2, 2012 at 3:15 PM, Uwe Kleine-K?nig > wrote: > > Hello, > > > > On Thu, Aug 02, 2012 at 11:03:31AM +0800, Lin Ming wrote: > >> I encountered a hard lockup on a armv5 board with 2.6.32 kernel. > >> There is no any message output since it is hard lockup. > >> > >> I tried watchdog, but watchdog can only reset the board. I still can't > >> get any info. > >> > >> The hard lockup is possibly because kernel blocked/looped with > >> interrupts disabled. > >> > >> Is there any non-maskable interrupt I can use to dump the kernel stack? > >> Or any other hint? > > Try enabling various debug options. The following come to (my) mind: > > > > CONFIG_DETECT_HUNG_TASK > > CONFIG_PROVE_LOCKING > > CONFIG_DEBUG_ATOMIC_SLEEP > > CONFIG_MAGIC_SYSRQ > > These debug options are already enabled. > But it doesn't help. then if you don't have a hardware debugger handy you can try https://lkml.org/lkml/2012/5/26/83 Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-K?nig | Industrial Linux Solutions | http://www.pengutronix.de/ |