From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752035AbeBZPbp (ORCPT ); Mon, 26 Feb 2018 10:31:45 -0500 Received: from mga07.intel.com ([134.134.136.100]:39490 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751628AbeBZPbj (ORCPT ); Mon, 26 Feb 2018 10:31:39 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.47,397,1515484800"; d="scan'208";a="33712202" From: Jani Nikula To: Chris Wilson , linux-kernel@vger.kernel.org Cc: intel-gfx@lists.freedesktop.org, Chris Wilson , Rusty Russell , Jean Delvare , Andrew Morton , Li Zhong , Petri Latvala , Daniel Vetter Subject: Re: [PATCH] kernel: Downgrade warning for unsafe parameters In-Reply-To: <20180226151919.9674-1-chris@chris-wilson.co.uk> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20180226151919.9674-1-chris@chris-wilson.co.uk> Date: Mon, 26 Feb 2018 17:31:32 +0200 Message-ID: <87tvu322ej.fsf@intel.com> 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 On Mon, 26 Feb 2018, Chris Wilson wrote: > As using an unsafe module parameter is, by its very definition, an > expected user action, emitting a warning is overkill. Nothing has yet > gone wrong, and we add a taint flag for any future oops should > something actually go wrong. So instead of having a user controllable > pr_warn, downgrade it to a pr_notice for "a normal, but significant > condition". > > We make use of unsafe kernel parameters in igt (we have not yet > succeeded in removing all such debugging options), which generates a > warning and taints the kernel. The warning is unhelpful as we then need > to filter it out again as we check that every test themselves do not > provoke any kernel warnings. IGT being https://cgit.freedesktop.org/drm/igt-gpu-tools/ for those not in the DRM/KMS circles. > References: 91f9d330cc14 ("module: make it possible to have unsafe, tainting module params") > Signed-off-by: Chris Wilson > Cc: Jani Nikula > Cc: Rusty Russell > Cc: Jean Delvare > Cc: Andrew Morton > Cc: Li Zhong > Cc: Petri Latvala > Cc: Daniel Vetter Acked-by: Jani Nikula When I added the unsafe module params, I erred on the side of making more noise about tainting, but there was really no discussion about it. FWIW, I don't mind the change, as long as it's not debug level. BR, Jani. > --- > kernel/params.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/kernel/params.c b/kernel/params.c > index cc9108c2a1fd..ce89f757e6da 100644 > --- a/kernel/params.c > +++ b/kernel/params.c > @@ -111,8 +111,8 @@ bool parameq(const char *a, const char *b) > static void param_check_unsafe(const struct kernel_param *kp) > { > if (kp->flags & KERNEL_PARAM_FL_UNSAFE) { > - pr_warn("Setting dangerous option %s - tainting kernel\n", > - kp->name); > + pr_notice("Setting dangerous option %s - tainting kernel\n", > + kp->name); > add_taint(TAINT_USER, LOCKDEP_STILL_OK); > } > } -- Jani Nikula, Intel Open Source Technology Center