From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965103AbdJRFfR (ORCPT ); Wed, 18 Oct 2017 01:35:17 -0400 Received: from ozlabs.org ([103.22.144.67]:50617 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965080AbdJRFfQ (ORCPT ); Wed, 18 Oct 2017 01:35:16 -0400 From: Michael Ellerman To: Andi Kleen , akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, Andi Kleen Subject: Re: [PATCH] Support resetting WARN*_ONCE In-Reply-To: <20171017214017.22708-1-andi@firstfloor.org> References: <20171017214017.22708-1-andi@firstfloor.org> Date: Wed, 18 Oct 2017 16:35:14 +1100 Message-ID: <87infdhvcd.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andi Kleen writes: > From: Andi Kleen > > I like _ONCE warnings because it's guaranteed that they don't > flood the log. > > During testing I find it useful to reset the state of the once warnings, > so that I can rerun tests and see if they trigger again, or can > guarantee that a test run always hits the same warnings. > > This patch adds a debugfs interface to reset all the _ONCE > warnings so that they appear again: > > echo 1 > /sys/kernel/debug/clear_warn_once > > This is implemented by putting all the warning booleans into > a special section, and clearing it. That won't work for arches that do the ONCE logic with a flag will it? ie. arm64, parisc, powerpc, s390, sh, x86. They use the version of WARN_ON_ONCE at line ~64 of bug.h #define __WARN_ONCE_TAINT(taint) __WARN_FLAGS(BUGFLAG_ONCE|BUGFLAG_TAINT(taint)) #define WARN_ON_ONCE(condition) ({ \ int __ret_warn_on = !!(condition); \ if (unlikely(__ret_warn_on)) \ __WARN_ONCE_TAINT(TAINT_WARN); \ unlikely(__ret_warn_on); \ }) cheers > diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h > index 87191357d303..68c2f08b7914 100644 > --- a/include/asm-generic/bug.h > +++ b/include/asm-generic/bug.h > @@ -129,7 +129,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint, > > #ifndef WARN_ON_ONCE > #define WARN_ON_ONCE(condition) ({ \ > - static bool __section(.data.unlikely) __warned; \ > + static bool __section(.data.once) __warned; \ > int __ret_warn_once = !!(condition); \ > \ > if (unlikely(__ret_warn_once && !__warned)) { \ > @@ -141,7 +141,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint, > #endif > > #define WARN_ONCE(condition, format...) ({ \ > - static bool __section(.data.unlikely) __warned; \ > + static bool __section(.data.once) __warned; \ > int __ret_warn_once = !!(condition); \ > \ > if (unlikely(__ret_warn_once && !__warned)) { \ > @@ -152,7 +152,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint, > }) > > #define WARN_TAINT_ONCE(condition, taint, format...) ({ \ > - static bool __section(.data.unlikely) __warned; \ > + static bool __section(.data.once) __warned; \ > int __ret_warn_once = !!(condition); \ > \ > if (unlikely(__ret_warn_once && !__warned)) { \