From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Andrzej Siewior Subject: Re: [PATCH rt] fix "list_bl.h: make list head locking RT safe" for !SMP && !DEBUG_SPINLOCK Date: Tue, 09 Jul 2013 09:39:14 +0200 Message-ID: <51DBBE22.8060403@linutronix.de> References: <1373322392-27604-1-git-send-email-u.kleine-koenig@pengutronix.de> <51DB40BA.60607@windriver.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: =?UTF-8?B?VXdlIEtsZWluZS1Lw7ZuaWc=?= , rostedt@goodmis.org, tglx@linutronix.de, paulmck@linux.vnet.ibm.com, linux-rt-users@vger.kernel.org, kernel@pengutronix.de To: Paul Gortmaker Return-path: Received: from www.linutronix.de ([62.245.132.108]:56046 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753062Ab3GIHjZ (ORCPT ); Tue, 9 Jul 2013 03:39:25 -0400 In-Reply-To: <51DB40BA.60607@windriver.com> Sender: linux-rt-users-owner@vger.kernel.org List-ID: On 07/09/2013 12:44 AM, Paul Gortmaker wrote: > On 13-07-08 06:26 PM, Uwe Kleine-K=C3=B6nig wrote: >> and so depending on LIST_BL_LOCKMASK being one. But LIST_BL_LOCKMASK= is >> only one if at least on of CONFIG_SMP and CONFIG_DEBUG_SPINLOCK are >> defined. Without these the value returned by hlist_bl_first has the >> zeroth bit set which likely results in a crash. >=20 > The incorrect assumption that I made was that the bit spin locks > still set/cleared the bit in the !SMP case. So if we set the bit > and the mask is zero, we get the mismatch, giving something like: >=20 > Acked-by: Paul Gortmaker > Tested-by: Paul Gortmaker Thanks everyone. >=20 > Thanks, > Paul. Sebastian -- To unsubscribe from this list: send the line "unsubscribe linux-rt-user= s" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html