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 7BC30C433EF for ; Mon, 4 Apr 2022 14:44:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1378209AbiDDOqs (ORCPT ); Mon, 4 Apr 2022 10:46:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52472 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1379351AbiDDOok (ORCPT ); Mon, 4 Apr 2022 10:44:40 -0400 Received: from mail-yb1-xb33.google.com (mail-yb1-xb33.google.com [IPv6:2607:f8b0:4864:20::b33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 77ABB1BE8B for ; Mon, 4 Apr 2022 07:40:09 -0700 (PDT) Received: by mail-yb1-xb33.google.com with SMTP id x21so11793660ybd.6 for ; Mon, 04 Apr 2022 07:40:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=pz3pYCujkv281hkCmxtkOvOxylf8pz3W8bcVxSFrQPo=; b=rp/qQxgcvWDdpmgA7fnhdYdZmKKGoA5Rh0NrghNK6QHGJaNrHNYoL1GD0Lo1sS0BUA Nby0xgsdoq1R6HeNh2u1Wkukpnqh5Ntkf5q76zL3bFMxJlmTeFTJnNsnhZRKvy55qwnZ slBewtIQuNbDNpCxmj1Fdp5nbCcMAsJsPryda6tMxoCyTky12lj33/ip4ciiZUz3koC/ szf7VWLN8gWAJvRw9nJCWeTApXNEDA5qLIldc38tppkwV5o9VxDq6OSye/JUfjA+DBO8 6/xeIsUOwgR8bNW/D7SxqiCFntXvCDnf4E8IDKNocpBYt9rOmdfd/xKobqm1+B6tbRe1 GBtQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=pz3pYCujkv281hkCmxtkOvOxylf8pz3W8bcVxSFrQPo=; b=xOZm9CyBbz/Um8Xsnu5UY/ph4rdMEGgmAI296sdx+pS5NofKdEz1+XwCFOdreWNo17 IdxekFY/TkK7qHXiyeSiY28wxPYEi+2Ey8vpxbv+IUhXPnPcAcDi1kG3/A9MGPzMBQgS AUGX1fsHyLE/vRAd5SU1V8jH12hDcs6zXvWlNkQwN/Dfl4Gxy7JRpGAfuQ2z4MsljtlG l21ts98NfHeQBwejYIqwFfc3bNsExPBZyMgSutkJluDEbTCGPpdTl9l/ME+QA4b3CpBz wqHTTW+cof7GjbEp3ABNDo+oY2LUgd2oxybkpObnIjHJ1CwGnuMkcGjmio9GIXP+YsgI zoqQ== X-Gm-Message-State: AOAM533E38eh/x4TyTcIyzmfP3+JjkVztJ1IHjOE1ee+gSHj3ZQJakTk A7YqwVkf7aHWWZGHYBwZJKRApGsMMOUyqqedW1npYw== X-Google-Smtp-Source: ABdhPJzn3nqxMsBH+7CEIPeIkwewLgc0IoSM83IwhtPQ5GBOQVPSfRg5TvY6utuFCSGhkNhPJBRtsnAq/8hPKoD3/xA= X-Received: by 2002:a25:3750:0:b0:634:6b89:ca9f with SMTP id e77-20020a253750000000b006346b89ca9fmr78127yba.363.1649083208503; Mon, 04 Apr 2022 07:40:08 -0700 (PDT) MIME-Version: 1.0 References: <20220329124017.737571-1-glider@google.com> <20220329124017.737571-14-glider@google.com> In-Reply-To: <20220329124017.737571-14-glider@google.com> From: Alexander Potapenko Date: Mon, 4 Apr 2022 16:39:31 +0200 Message-ID: Subject: Re: [PATCH v2 13/48] kmsan: add KMSAN runtime core To: Alexander Potapenko Cc: Alexander Viro , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , Linux Memory Management List , Linux-Arch , LKML Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > +depot_stack_handle_t kmsan_save_stack_with_flags(gfp_t flags, > + unsigned int extra) > +{ > + unsigned long entries[KMSAN_STACK_DEPTH]; > + unsigned int nr_entries; > + > + nr_entries = stack_trace_save(entries, KMSAN_STACK_DEPTH, 0); > + nr_entries = filter_irq_stacks(entries, nr_entries); This is redundant, __stack_depot_save() below already calls filter_irq_stacks(). > + > + if (depth >= MAX_CHAIN_DEPTH) { > + static atomic_long_t kmsan_skipped_origins; > + long skipped = atomic_long_inc_return(&kmsan_skipped_origins); > + > + if (skipped % NUM_SKIPPED_TO_WARN == 0) { > + pr_warn("not chained %ld origins\n", skipped); > + dump_stack(); > + kmsan_print_origin(id); > + } > + return id; > + } > + depth++; > + extra_bits = kmsan_extra_bits(depth, uaf); > + > + entries[0] = KMSAN_CHAIN_MAGIC_ORIGIN; > + entries[1] = kmsan_save_stack_with_flags(GFP_ATOMIC, 0); > + entries[2] = id; > + return __stack_depot_save(entries, ARRAY_SIZE(entries), extra_bits, > + GFP_ATOMIC, true); @entries is initialized in non-instrumented code, so passing it to filter_irq_stacks() etc. will result in false positives, unless we explicitly unpoison it. (right now KMSAN does not instrument kernel/stacktrace.c, but it probably should)