[PATCH v2 1/5] printk/nmi: Generic solution for safe printk in NMI
From: pmladek@suse.com (Petr Mladek)
Date: 2016-03-18 10:03:16
Also in:
linux-mips, linux-sh, linuxppc-dev, lkml, sparclinux
On Thu 2016-03-17 12:35:27, Andrew Morton wrote:
On Fri, 4 Dec 2015 17:57:44 +0100 Petr Mladek [off-list ref] wrote:quoted
On Wed 2015-12-02 00:24:49, Jiri Kosina wrote:quoted
On Fri, 27 Nov 2015, Petr Mladek wrote:quoted
MN10300 has its own implementation for entering and exiting NMI handlers. It does not call nmi_enter() and nmi_exit(). Please, find below an updated patch that adds printk_nmi_enter() and printk_nmi_exit() to the custom entry points. Then we could add HAVE_NMI to arch/mn10300/Kconfig and avoid the above warning.Hmm, so what exactly would go wrong if MN10300 (whatever that architecture is) would call nmi_enter() and nmi_exit() at the places where it's starting and finishing NMI handler?quoted
From a cursory look, it seems like most (if not all) of the things calledfrom nmi_{enter,exit}() would be nops there anyway.Good point. Max mentioned in the other main that the NMI handler should follow the NMI ruler. I do not why it could not work. In fact, it might improve things, e.g. nmi_enter() blocks recursive NMIs. I think that it will move it into a separate patch, thought.I've sort of lost the plot on this patchset. I know Daniel had concerns (resolved?). Sergey lost the ability to perform backtraces and has a proposed fix ("printk/nmi: restore printk_func in nmi_panic") but that wasn't fully resolved and I didn't merge anything. I'm not sure what Jan's thinking is on it all. So... I'll retain printk-nmi-generic-solution-for-safe-printk-in-nmi.patch printk-nmi-use-irq-work-only-when-ready.patch printk-nmi-warn-when-some-message-has-been-lost-in-nmi-context.patch printk-nmi-increase-the-size-of-nmi-buffer-and-make-it-configurable.patch in -mm for now. Perhaps I should drop them all and we start again after -rc1?
Please, drop it for now. I'll send an updated version that will better handle Daniel's concerns after rc1. I thought that it had already been decided. You wanted to remove the patchset in favour of "improvements to the nmi_backtrace code" by Chris Metcalf, see http://thread.gmane.org/gmane.linux.ports.arm.kernel/482845/focus=483002 Best Regards, Petr