From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7C8643AA507; Tue, 17 Mar 2026 11:30:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773747049; cv=none; b=pEV5CZLNEpkIqi1MD+aySl0WmsN+M3P6sy8r6jo0u4bMDkhjH+a7/yr6+un89R66bPC+Tncan8CEXiOciIRFmW/Yjf476c3cmrdS3cSb12eMN4CuskFjOdbEDZJvjRHkr3RSArNdmMr/9S8SEQL2FH0LADF3cVUGIZ+usf+oKS0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773747049; c=relaxed/simple; bh=i2HaGDScAKsWKuc9UfzpprQdN3BOKyxmGHzuC2u7FvE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=KQ1i36sbf75swy+KFH6VFgOkMQnQ5wKVBlOd5GqN2hXwwWgeoxtsksnXZMfn+HwrouNVWrzY/n7z/vkXN5Lo5o9eBnnZEFueKnaL79S6PDFH1FwrmG1WF6HbWEthgkO953nhYO7/G0hQwlrkBC8M02pN6s7x5Y/RaAkubSINEXA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=NsavaPYY; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="NsavaPYY" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=6RYWarEzFu75TQfhyGtGIrajfUm5t79UfcymHu8wzk0=; b=NsavaPYY2EaF1ZEYrjdnqM0/D8 sGyTUkaQNnUPZZ7mKVwOyCMn1h++U47Qfde/FrENxkEG1/kY33oLp0gIqkRfHZuLFmotzDWTdViCa nFIPQl+pE+kT8V16jFVOnwFKrbpfIpGKQLzTBEomtAdYWuh1bS78g0zhQkBlLpBu7bRPIRD4kFLXA +gHwndSKh6WxO50d9HWXkOXXjw7BJDRGIuHVAZAad3J829AWNdDPzjy0PlOmnVTIvuVN8fOVWj0cw twtdZ4sDc+4mT+wZEqXXOKCgwdV2k1tjFW9nqPn2raJu/l3xctBttIFEHmx1fbjc/KJlNOQThGvoO r9/VK+EQ==; Received: from 2001-1c00-8d85-5700-266e-96ff-fe07-7dcc.cable.dynamic.v6.ziggo.nl ([2001:1c00:8d85:5700:266e:96ff:fe07:7dcc] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1w2Sd1-00000002bqs-0BeC; Tue, 17 Mar 2026 11:30:27 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id F3E9A303244; Tue, 17 Mar 2026 12:30:25 +0100 (CET) Date: Tue, 17 Mar 2026 12:30:25 +0100 From: Peter Zijlstra To: "Vlastimil Babka (SUSE)" Cc: Albert Esteve , Arnd Bergmann , Brendan Higgins , David Gow , Rae Moar , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Jonathan Corbet , Shuah Khan , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org, kunit-dev@googlegroups.com, dri-devel@lists.freedesktop.org, workflows@vger.kernel.org, linux-doc@vger.kernel.org, Alessandro Carminati , Guenter Roeck , Kees Cook , Linux Kernel Functional Testing , Dan Carpenter , =?iso-8859-1?Q?Ma=EDra?= Canal , Simona Vetter Subject: Re: [PATCH v6 0/5] kunit: Add support for suppressing warning backtraces Message-ID: <20260317113025.GG2872@noisy.programming.kicks-ass.net> References: <20260317-kunit_add_support-v6-0-dd22aeb3fe5d@redhat.com> <69f4eb09-efbd-4bd1-81b8-963b78e1a3a3@kernel.org> Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <69f4eb09-efbd-4bd1-81b8-963b78e1a3a3@kernel.org> On Tue, Mar 17, 2026 at 12:20:26PM +0100, Vlastimil Babka (SUSE) wrote: > > For this iteration, the `__report_bug()` centralized approach was > > revisited after the discussion in the previous version [1]. > > Discussion with PeterZ, who is not CC'd here? (did it now for my reply). > > > However, again this approach did not work because: > > - Some warning output is generated directly in the macros before calling > > the centralized functions (e.g., `__warn_printk()` in `__WARN_printf()`) > > - Functions in the warning path like `warn_slowpath_fmt()` are marked > > `__always_inline`, making it difficult to intercept early enough > > - So, by the time `__report_bug()` is called, output has already been written > > to the console, making suppression ineffective > > > > Current Proposal: Check Directly in the `WARN()` Macros. > > This avoids the need for function symbol resolution or ELF section > > modification. > > Suppression is implemented directly in the `WARN*()` macros. > > So does that bloat every warn/bug site (as Peter objected to) or not? > And is it compatible with x86? I see you modify include/asm-generic/bug.h > but x86 has its own version of e.g. __WARN_printf ? Yeah, they done it all wrong again :-( This should be pushed inside __report_bug() through __WARN_printf with a new BUGFLAG thing. So NAK from me on this -- again!