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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C28BC433DF for ; Fri, 22 May 2020 23:42:51 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C8FD32073B for ; Fri, 22 May 2020 23:42:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="mwbCPnxS" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C8FD32073B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4581980008; Fri, 22 May 2020 19:42:50 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4080E80007; Fri, 22 May 2020 19:42:50 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 31CE180008; Fri, 22 May 2020 19:42:50 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0153.hostedemail.com [216.40.44.153]) by kanga.kvack.org (Postfix) with ESMTP id 1961480007 for ; Fri, 22 May 2020 19:42:50 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id CE9008248D7C for ; Fri, 22 May 2020 23:42:49 +0000 (UTC) X-FDA: 76845982458.22.actor03_8d17a2ac5d91e X-HE-Tag: actor03_8d17a2ac5d91e X-Filterd-Recvd-Size: 2508 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf39.hostedemail.com (Postfix) with ESMTP for ; Fri, 22 May 2020 23:42:49 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2AF7920723; Fri, 22 May 2020 23:42:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590190968; bh=oahDcicwRFmo7/2GQGTQCHhUqocnHDwRWsWdm6Vbj18=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=mwbCPnxSc1pHdTkJMGmdYuU4RRLMPHYzf+jyG6Vu/zjQAPp/1mR5uveeunjxJCkuJ rBrjbgHjBuYtcltp2UqKHcxUBGIEpCbynv5R/0dZR6CdDrGjMmAC2R5lpIKTPGRmM3 c2zoIl/7eVgAHc57ZMfGRoJ0R8BsTLQ/e48aaH+c= Date: Fri, 22 May 2020 16:42:47 -0700 From: Andrew Morton To: Marco Elver Cc: dvyukov@google.com, glider@google.com, andreyknvl@google.com, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, aryabinin@virtuozzo.com, linux-mm@kvack.org, cai@lca.pw, kernel test robot Subject: Re: [PATCH v2] kasan: Disable branch tracing for core runtime Message-Id: <20200522164247.4a88aed496f0feb458d8bca0@linux-foundation.org> In-Reply-To: <20200522075207.157349-1-elver@google.com> References: <20200522075207.157349-1-elver@google.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, 22 May 2020 09:52:07 +0200 Marco Elver wrote: > During early boot, while KASAN is not yet initialized, it is possible to > enter reporting code-path and end up in kasan_report(). While > uninitialized, the branch there prevents generating any reports, > however, under certain circumstances when branches are being traced > (TRACE_BRANCH_PROFILING), we may recurse deep enough to cause kernel > reboots without warning. > > To prevent similar issues in future, we should disable branch tracing > for the core runtime. > > Link: https://lore.kernel.org/lkml/20200517011732.GE24705@shao2-debian/ > Reported-by: kernel test robot > Signed-off-by: Marco Elver I assume this affects 5.6 and perhaps earlier kernels? I also assume that a cc:stable is appropriate for this fix?