From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:44128 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754580AbeCRQFQ (ORCPT ); Sun, 18 Mar 2018 12:05:16 -0400 Subject: Patch "powerpc/xmon: Fix an unexpected xmon on/off state change" has been added to the 4.9-stable tree To: xinhui.pan@linux.vnet.ibm.com, alexander.levin@microsoft.com, gpiccoli@linux.vnet.ibm.com, gregkh@linuxfoundation.org, mpe@ellerman.id.au Cc: , From: Date: Sun, 18 Mar 2018 17:03:51 +0100 Message-ID: <152138903112121@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled powerpc/xmon: Fix an unexpected xmon on/off state change to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-xmon-fix-an-unexpected-xmon-on-off-state-change.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Sun Mar 18 16:55:33 CET 2018 From: Pan Xinhui Date: Wed, 22 Mar 2017 16:27:49 -0300 Subject: powerpc/xmon: Fix an unexpected xmon on/off state change From: Pan Xinhui [ Upstream commit 3b5bf42b81d56085fd58692b5117f69aa77fdff7 ] Once xmon is triggered by sysrq-x, it is enabled always afterwards even if it is disabled during boot. This will cause a system reset interrupt fail to dump. So keep xmon in its original state after exit. We have several ways to set xmon on or off. 1) by a build config CONFIG_XMON_DEFAULT. 2) by a boot cmdline with xmon or xmon=early or xmon=on to enable xmon and xmon=off to disable xmon. This value will override that in step 1. 3) by a debugfs interface, as proposed in this patchset. And this value can override those in step 1 and 2. Signed-off-by: Pan Xinhui Signed-off-by: Guilherme G. Piccoli Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/xmon/xmon.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -74,6 +74,7 @@ static int xmon_gate; #endif /* CONFIG_SMP */ static unsigned long in_xmon __read_mostly = 0; +static int xmon_on = IS_ENABLED(CONFIG_XMON_DEFAULT); static unsigned long adrs; static int size = 1; @@ -3244,6 +3245,8 @@ static void sysrq_handle_xmon(int key) /* ensure xmon is enabled */ xmon_init(1); debugger(get_irq_regs()); + if (!xmon_on) + xmon_init(0); } static struct sysrq_key_op sysrq_xmon_op = { @@ -3260,7 +3263,7 @@ static int __init setup_xmon_sysrq(void) __initcall(setup_xmon_sysrq); #endif /* CONFIG_MAGIC_SYSRQ */ -static int __initdata xmon_early, xmon_off; +static int __initdata xmon_early; static int __init early_parse_xmon(char *p) { @@ -3268,10 +3271,12 @@ static int __init early_parse_xmon(char /* just "xmon" is equivalent to "xmon=early" */ xmon_init(1); xmon_early = 1; - } else if (strncmp(p, "on", 2) == 0) + xmon_on = 1; + } else if (strncmp(p, "on", 2) == 0) { xmon_init(1); - else if (strncmp(p, "off", 3) == 0) - xmon_off = 1; + xmon_on = 1; + } else if (strncmp(p, "off", 3) == 0) + xmon_on = 0; else if (strncmp(p, "nobt", 4) == 0) xmon_no_auto_backtrace = 1; else @@ -3283,10 +3288,8 @@ early_param("xmon", early_parse_xmon); void __init xmon_setup(void) { -#ifdef CONFIG_XMON_DEFAULT - if (!xmon_off) + if (xmon_on) xmon_init(1); -#endif if (xmon_early) debugger(NULL); } Patches currently in stable-queue which might be from xinhui.pan@linux.vnet.ibm.com are queue-4.9/powerpc-xmon-fix-an-unexpected-xmon-on-off-state-change.patch