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=-12.7 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLACK, URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 6B413C433DF for ; Fri, 22 May 2020 07:54:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1FC2B2072C for ; Fri, 22 May 2020 07:54:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Js0gHi2D" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1FC2B2072C Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BADF380008; Fri, 22 May 2020 03:54:22 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B37BB80007; Fri, 22 May 2020 03:54:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9FF8380008; Fri, 22 May 2020 03:54:22 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0106.hostedemail.com [216.40.44.106]) by kanga.kvack.org (Postfix) with ESMTP id 85D4E80007 for ; Fri, 22 May 2020 03:54:22 -0400 (EDT) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 4B80852CC for ; Fri, 22 May 2020 07:54:22 +0000 (UTC) X-FDA: 76843592364.26.stem68_904342065d4e X-HE-Tag: stem68_904342065d4e X-Filterd-Recvd-Size: 5615 Received: from mail-oi1-f195.google.com (mail-oi1-f195.google.com [209.85.167.195]) by imf17.hostedemail.com (Postfix) with ESMTP for ; Fri, 22 May 2020 07:54:21 +0000 (UTC) Received: by mail-oi1-f195.google.com with SMTP id w4so8603892oia.1 for ; Fri, 22 May 2020 00:54:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=HDvjesLpXeZbOqZwVDwcodT/WLJvvTdpPsS1Pe0Kvbc=; b=Js0gHi2DTQXexCVkMMsYhKEUAtqsQlbamMG8UNpINiLEKQLXsSUxNqSgvgPf14hal3 Cr7pYIkHBer06P3K+5PRh4agENlFTgSahNc5+iggMr7ET47z/yWICl26a6zfOcGcrWZr GGhFLk0+IxVNvDfcDbY2RlgjIOIZTVtgYm1YDntFMLdfbs+GtT8Q6mqc/bVpj4lf8eHd vf6E0yIlumIhD9+RhHj3kVypUjknM861hAwo7tz+qajVzsmfqSvrvR7yitsY4yDPGAIV ugyi8jD7hPk7P3lObtJLvP6Y+QTjdAgUnFS0QwuzPWnXnlzqUnBX7hdPpuxe3jXn/+TT b0ew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=HDvjesLpXeZbOqZwVDwcodT/WLJvvTdpPsS1Pe0Kvbc=; b=pPwch2y6RZ5p42/uzIxA7mkQ07karFz0bGy+J/OUY7iVMAaIPXexNHt4138nZfPDI2 EDsnwhX23V/Ug96USzTbMrvMbB8m2AImzeqqTN3irj1VXZFjNzI6uLOvrIDcNWHH7cxE K6HsOrZZvSrV0SltlIo38IDnEcLD7PsBFQXbwZDsy/HdoBovU/MGP4PA2Z1RVvS2smtw gmXPPDhOmvasCD69b0a/xmdkE9FLmtf2I6VBV6Uf+K8uKdko1QU+IHkzBwex7qwta+4A es0Zc3jPM7K1YCmKhqh+2nPt6anvNvkFLG275e9qAccH390oY+6muInXQZQOdwH13Czg VTAA== X-Gm-Message-State: AOAM532/+O6QqhjNQsVteDY2xedVUb0NYSSwt5B/XzZaZt2+3uX2m4OI I6wOsdQc0O9bK/x/fbpa5edip2YPZp0yVanvsF5L6g== X-Google-Smtp-Source: ABdhPJzpxaj9HyQhPfTgF5R8Pm35E6TnT6e1FhWP001/HepyJH8a5IroXY25wt0UAemMj/6k2gfyh6HP4yUtrM6aJ7Y= X-Received: by 2002:aca:3254:: with SMTP id y81mr1737976oiy.172.1590134060936; Fri, 22 May 2020 00:54:20 -0700 (PDT) MIME-Version: 1.0 References: <20200519182459.87166-1-elver@google.com> <20200521221133.GD6367@ovpn-112-192.phx2.redhat.com> In-Reply-To: <20200521221133.GD6367@ovpn-112-192.phx2.redhat.com> From: Marco Elver Date: Fri, 22 May 2020 09:54:09 +0200 Message-ID: Subject: Re: [PATCH] kasan: Disable branch tracing for core runtime To: Qian Cai Cc: Dmitry Vyukov , Alexander Potapenko , Andrey Konovalov , LKML , kasan-dev , Andrey Ryabinin , Andrew Morton , Linux Memory Management List , kernel test robot Content-Type: text/plain; charset="UTF-8" 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 at 00:11, Qian Cai wrote: > > On Tue, May 19, 2020 at 08:24:59PM +0200, 'Marco Elver' via kasan-dev 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 > > --- > > mm/kasan/Makefile | 16 ++++++++-------- > > mm/kasan/generic.c | 1 - > > 2 files changed, 8 insertions(+), 9 deletions(-) > > > > diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile > > index 434d503a6525..de3121848ddf 100644 > > --- a/mm/kasan/Makefile > > +++ b/mm/kasan/Makefile > > @@ -15,14 +15,14 @@ CFLAGS_REMOVE_tags_report.o = $(CC_FLAGS_FTRACE) > > > > # Function splitter causes unnecessary splits in __asan_load1/__asan_store1 > > # see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63533 > > -CFLAGS_common.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > > -CFLAGS_generic.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > > -CFLAGS_generic_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > > -CFLAGS_init.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > > -CFLAGS_quarantine.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > > -CFLAGS_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > > -CFLAGS_tags.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) > > mm/kasan/tags.c:15:9: warning: 'DISABLE_BRANCH_PROFILING' macro redefined [-Wmacro-redefined] > #define DISABLE_BRANCH_PROFILING > ^ > :6:9: note: previous definition is here > #define DISABLE_BRANCH_PROFILING 1 > ^ > > This? > > diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c > index 25b7734e7013..8a959fdd30e3 100644 > --- a/mm/kasan/tags.c > +++ b/mm/kasan/tags.c > @@ -12,7 +12,6 @@ > */ > > #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > -#define DISABLE_BRANCH_PROFILING > > #include > #include > I missed this one, thanks! Added this to v2. v2: https://lkml.kernel.org/r/20200522075207.157349-1-elver@google.com