From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751616AbdF1JTr (ORCPT ); Wed, 28 Jun 2017 05:19:47 -0400 Received: from [140.206.112.106] ([140.206.112.106]:4921 "EHLO mail2012.asrmicro.com" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751513AbdF1JTh (ORCPT ); Wed, 28 Jun 2017 05:19:37 -0400 X-Greylist: delayed 904 seconds by postgrey-1.27 at vger.kernel.org; Wed, 28 Jun 2017 05:19:37 EDT From: Qiao Zhou To: , , , , , , , , , CC: Qiao Zhou Subject: [PATCH] arm64: traps: disable irq in die() Date: Wed, 28 Jun 2017 17:04:12 +0800 Message-ID: <1498640652-23338-2-git-send-email-qiaozhou@asrmicro.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1498640652-23338-1-git-send-email-qiaozhou@asrmicro.com> References: <1498640652-23338-1-git-send-email-qiaozhou@asrmicro.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.1.50.16] X-ClientProxiedBy: mail2012.asrmicro.com (10.1.24.123) To mail2012.asrmicro.com (10.1.24.123) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In current die(), the irq is disabled for __die() handle, not including the possible panic() handling. Since the log in __die() can take several hundreds ms, new irq might come and interrupt current die(). If the process calling die() holds some critical resource, and some other process scheduled later also needs it, then it would deadlock. The first panic will not be executed. So here disable irq for the whole flow of die(). Signed-off-by: Qiao Zhou --- arch/arm64/kernel/traps.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 0805b44..b12bf0f 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -274,10 +274,13 @@ static DEFINE_RAW_SPINLOCK(die_lock); void die(const char *str, struct pt_regs *regs, int err) { int ret; + unsigned long flags; + + local_irq_save(flags); oops_enter(); - raw_spin_lock_irq(&die_lock); + raw_spin_lock(&die_lock); console_verbose(); bust_spinlocks(1); ret = __die(str, err, regs); @@ -287,13 +290,16 @@ void die(const char *str, struct pt_regs *regs, int err) bust_spinlocks(0); add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); - raw_spin_unlock_irq(&die_lock); + raw_spin_unlock(&die_lock); oops_exit(); if (in_interrupt()) panic("Fatal exception in interrupt"); if (panic_on_oops) panic("Fatal exception"); + + local_irq_restore(flags); + if (ret != NOTIFY_STOP) do_exit(SIGSEGV); } -- 2.7.4 From mboxrd@z Thu Jan 1 00:00:00 1970 From: qiaozhou@asrmicro.com (Qiao Zhou) Date: Wed, 28 Jun 2017 17:04:12 +0800 Subject: [PATCH] arm64: traps: disable irq in die() In-Reply-To: <1498640652-23338-1-git-send-email-qiaozhou@asrmicro.com> References: <1498640652-23338-1-git-send-email-qiaozhou@asrmicro.com> Message-ID: <1498640652-23338-2-git-send-email-qiaozhou@asrmicro.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org In current die(), the irq is disabled for __die() handle, not including the possible panic() handling. Since the log in __die() can take several hundreds ms, new irq might come and interrupt current die(). If the process calling die() holds some critical resource, and some other process scheduled later also needs it, then it would deadlock. The first panic will not be executed. So here disable irq for the whole flow of die(). Signed-off-by: Qiao Zhou --- arch/arm64/kernel/traps.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 0805b44..b12bf0f 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -274,10 +274,13 @@ static DEFINE_RAW_SPINLOCK(die_lock); void die(const char *str, struct pt_regs *regs, int err) { int ret; + unsigned long flags; + + local_irq_save(flags); oops_enter(); - raw_spin_lock_irq(&die_lock); + raw_spin_lock(&die_lock); console_verbose(); bust_spinlocks(1); ret = __die(str, err, regs); @@ -287,13 +290,16 @@ void die(const char *str, struct pt_regs *regs, int err) bust_spinlocks(0); add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); - raw_spin_unlock_irq(&die_lock); + raw_spin_unlock(&die_lock); oops_exit(); if (in_interrupt()) panic("Fatal exception in interrupt"); if (panic_on_oops) panic("Fatal exception"); + + local_irq_restore(flags); + if (ret != NOTIFY_STOP) do_exit(SIGSEGV); } -- 2.7.4