Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755862AbYJVKhz (ORCPT ); Wed, 22 Oct 2008 06:37:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753365AbYJVKhr (ORCPT ); Wed, 22 Oct 2008 06:37:47 -0400 Received: from m-relay2.rz.uni-saarland.de ([134.96.7.8]:8822 "EHLO eris.rz.uni-saarland.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753269AbYJVKhq (ORCPT ); Wed, 22 Oct 2008 06:37:46 -0400 From: Alexander van Heukelum To: Neil Horman , Ingo Molnar , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, vgoyal@redhat.com, hbabu@us.ibm.com, hpa@zytor.com, akpm@linux-foundation.org, Alexander van Heukelum , ebiederm@xmission.com, tglx@linutronix.de Cc: Alexander van Heukelum Subject: [PATCH 5/7] i386, dumpstack: use x86_64's method to account die_nest_count Date: Wed, 22 Oct 2008 12:00:12 +0200 Message-Id: <1224669614-25863-6-git-send-email-heukelum@fastmail.fm> X-Mailer: git-send-email 1.5.4.3 In-Reply-To: <1224669614-25863-5-git-send-email-heukelum@fastmail.fm> References: <1224669614-25863-1-git-send-email-heukelum@fastmail.fm> <1224669614-25863-2-git-send-email-heukelum@fastmail.fm> <1224669614-25863-3-git-send-email-heukelum@fastmail.fm> <1224669614-25863-4-git-send-email-heukelum@fastmail.fm> <1224669614-25863-5-git-send-email-heukelum@fastmail.fm> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-3.0 (eris.rz.uni-saarland.de [134.96.7.8]); Wed, 22 Oct 2008 12:36:43 +0200 (CEST) X-AntiVirus: checked by AntiVir MailGate (version: 2.1.2-14; AVE: 7.9.0.5; VDF: 7.0.7.72; host: AntiVir2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2095 Lines: 75 oops_begin/oops_end should always be used in pairs. On x86_64 oops_begin increments die_nest_count, and oops_end decrements die_nest_count. Doing this makes oops_begin and oops_end equal to the x86_64 versions. Signed-off-by: Alexander van Heukelum --- arch/x86/kernel/dumpstack_32.c | 29 +++++++++++++++++------------ 1 files changed, 17 insertions(+), 12 deletions(-) diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c index a29b88f..7c7d691 100644 --- a/arch/x86/kernel/dumpstack_32.c +++ b/arch/x86/kernel/dumpstack_32.c @@ -289,21 +289,24 @@ static unsigned int die_nest_count; unsigned __kprobes long oops_begin(void) { + int cpu; unsigned long flags; oops_enter(); - if (die_owner != raw_smp_processor_id()) { - console_verbose(); - raw_local_irq_save(flags); - __raw_spin_lock(&die_lock); - die_owner = smp_processor_id(); - die_nest_count = 0; - bust_spinlocks(1); - } else { - raw_local_irq_save(flags); + /* racy, but better than risking deadlock. */ + raw_local_irq_save(flags); + cpu = smp_processor_id(); + if (!__raw_spin_trylock(&die_lock)) { + if (cpu == die_owner) + /* nested oops. should stop eventually */; + else + __raw_spin_lock(&die_lock); } die_nest_count++; + die_owner = cpu; + console_verbose(); + bust_spinlocks(1); return flags; } @@ -315,13 +318,15 @@ void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr) bust_spinlocks(0); die_owner = -1; add_taint(TAINT_DIE); - __raw_spin_unlock(&die_lock); + die_nest_count--; + if (!die_nest_count) + /* Nest count reaches zero, release the lock. */ + __raw_spin_unlock(&die_lock); raw_local_irq_restore(flags); - oops_exit(); + if (!signr) return; - if (in_interrupt()) panic("Fatal exception in interrupt"); if (panic_on_oops) -- 1.5.4.3 -- 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/