From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C30A3C4332F for ; Wed, 2 Nov 2022 12:53:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231197AbiKBMxH (ORCPT ); Wed, 2 Nov 2022 08:53:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33230 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231199AbiKBMxE (ORCPT ); Wed, 2 Nov 2022 08:53:04 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 143CE24F11 for ; Wed, 2 Nov 2022 05:53:04 -0700 (PDT) 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=h2SE5RwKBCcdzUwbfaFdZfsZyswNYZ6Fa+MR9Z7llwo=; b=JOtPhia4qQjDFmq7/FCisGmLAq C/3jwbcF1PMvrLjIB7K7o4ODEpIVynbT2B+DuP624X/aoG43q56GDsTicBTkA2l5T+tVcIwGvw5fx S4fCJVaBG8fAueb4d0qxhCX3w1hnnLC6ClEntC7kib+bSTUWTKRh6AMNSNNypctakH7lVplAxpFhT bPXwtvwbtBr0oI1miYeSM5nnwYLfu6BZExWN2DDqZMre0rJxmZoLpUG+R3rsAtKGx1FUbB+FtkUH4 4rM2uvoEPfVAkgJHadM5YF6nkyOpFCIzLJhqC2ExdTlANpKQVaBEmt+n1YJbFtaoySKzwp5G8IJ8Z RPp17Dng==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1oqDEw-005WV4-0O; Wed, 02 Nov 2022 12:53:06 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id C57C530031B; Wed, 2 Nov 2022 13:53:00 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id B6B0720B1E7E3; Wed, 2 Nov 2022 13:53:00 +0100 (CET) Date: Wed, 2 Nov 2022 13:53:00 +0100 From: Peter Zijlstra To: Alexander Potapenko Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Dmitry Vyukov , Marco Elver Subject: Re: [PATCH 4/5] kmsan: make sure PREEMPT_RT is off Message-ID: References: <20221102110611.1085175-1-glider@google.com> <20221102110611.1085175-4-glider@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221102110611.1085175-4-glider@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 02, 2022 at 12:06:10PM +0100, Alexander Potapenko wrote: > As pointed out by Peter Zijlstra, __msan_poison_alloca() does not play > well with IRQ code when PREEMPT_RT is on, because in that mode even > GFP_ATOMIC allocations cannot be performed. > > Fixing this would require making stackdepot completely lockless, which > is quite challenging and may be excessive for the time being. > > Instead, make sure KMSAN is incompatible with PREEMPT_RT, like other > debug configs are. > > Cc: Andrew Morton > Cc: Dmitry Vyukov > Cc: Marco Elver > Cc: Peter Zijlstra (Intel) > Link: https://lore.kernel.org/lkml/20221025221755.3810809-1-glider@google.com/ > Signed-off-by: Alexander Potapenko Acked-by: Peter Zijlstra (Intel) > --- > lib/Kconfig.kmsan | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/lib/Kconfig.kmsan b/lib/Kconfig.kmsan > index b2489dd6503fa..ef2c8f256c57d 100644 > --- a/lib/Kconfig.kmsan > +++ b/lib/Kconfig.kmsan > @@ -12,6 +12,7 @@ config KMSAN > bool "KMSAN: detector of uninitialized values use" > depends on HAVE_ARCH_KMSAN && HAVE_KMSAN_COMPILER > depends on SLUB && DEBUG_KERNEL && !KASAN && !KCSAN > + depends on !PREEMPT_RT > select STACKDEPOT > select STACKDEPOT_ALWAYS_INIT > help > -- > 2.38.1.273.g43a17bfeac-goog >