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 11CEBC61DA4 for ; Mon, 6 Mar 2023 20:59:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229559AbjCFU7i (ORCPT ); Mon, 6 Mar 2023 15:59:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47992 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229653AbjCFU7g (ORCPT ); Mon, 6 Mar 2023 15:59:36 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0C08498A1 for ; Mon, 6 Mar 2023 12:59:31 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 3FED7B81128 for ; Mon, 6 Mar 2023 20:59:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF0F5C433EF; Mon, 6 Mar 2023 20:59:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1678136368; bh=gCYELjDaj0q43d2getloFIPcbvY0PeL4/BoqsOAd5iI=; h=Date:To:From:Subject:From; b=z2i+Ki5Y7XRRd12ovCKhvQo0KbWqb8cbqOoHpZTcAHwIUCp0vz4952ByZuJD6Fufh fWtLSYU9TOC5aqWgAuFLDQR3tHi3mcsyLmGjuaBNDZZ4hiJn2HNCC7tx53xbI02J+q V/8ghXp89+bw+MoDVniLgimjKS4vK52zBHvBpslo= Date: Mon, 06 Mar 2023 12:59:28 -0800 To: mm-commits@vger.kernel.org, syzkaller@googlegroups.com, elver@google.com, dvyukov@google.com, andreyknvl@gmail.com, glider@google.com, akpm@linux-foundation.org From: Andrew Morton Subject: + lib-stackdepot-kmsan-mark-api-outputs-as-initialized.patch added to mm-unstable branch Message-Id: <20230306205928.CF0F5C433EF@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: lib/stackdepot: kmsan: mark API outputs as initialized has been added to the -mm mm-unstable branch. Its filename is lib-stackdepot-kmsan-mark-api-outputs-as-initialized.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/lib-stackdepot-kmsan-mark-api-outputs-as-initialized.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Alexander Potapenko Subject: lib/stackdepot: kmsan: mark API outputs as initialized Date: Mon, 6 Mar 2023 12:13:21 +0100 KMSAN does not instrument stackdepot and may treat memory allocated by it as uninitialized. This is not a problem for KMSAN itself, because its functions calling stackdepot API are also not instrumented. But other kernel features (e.g. netdev tracker) may access stack depot from instrumented code, which will lead to false positives, unless we explicitly mark stackdepot outputs as initialized. Link: https://lkml.kernel.org/r/20230306111322.205724-1-glider@google.com Signed-off-by: Alexander Potapenko Reported-by: syzbot Reviewed-by: Dmitry Vyukov Suggested-by: Dmitry Vyukov Cc: Andrey Konovalov Cc: Marco Elver Signed-off-by: Andrew Morton --- --- a/lib/stackdepot.c~lib-stackdepot-kmsan-mark-api-outputs-as-initialized +++ a/lib/stackdepot.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include #include @@ -306,6 +307,11 @@ depot_alloc_stack(unsigned long *entries stack->handle.extra = 0; memcpy(stack->entries, entries, flex_array_size(stack, entries, size)); pool_offset += required_size; + /* + * Let KMSAN know the stored stack record is initialized. This shall + * prevent false positive reports if instrumented code accesses it. + */ + kmsan_unpoison_memory(stack, required_size); return stack; } @@ -465,6 +471,12 @@ unsigned int stack_depot_fetch(depot_sta struct stack_record *stack; *entries = NULL; + /* + * Let KMSAN know *entries is initialized. This shall prevent false + * positive reports if instrumented code accesses it. + */ + kmsan_unpoison_memory(entries, sizeof(*entries)); + if (!handle) return 0; _ Patches currently in -mm which might be from glider@google.com are x86-kmsan-dont-rename-memintrinsics-in-uninstrumented-files.patch kmsan-another-take-at-fixing-memcpy-tests.patch x86-kmsan-use-c-versions-of-memset16-memset32-memset64.patch kmsan-add-memsetxx-tests.patch lib-stackdepot-kmsan-mark-api-outputs-as-initialized.patch kmsan-add-test_stackdepot_roundtrip.patch