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 270EAC4332F for ; Fri, 18 Nov 2022 17:23:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242516AbiKRRXO (ORCPT ); Fri, 18 Nov 2022 12:23:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56072 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234973AbiKRRXM (ORCPT ); Fri, 18 Nov 2022 12:23:12 -0500 Received: from mail-ej1-x64a.google.com (mail-ej1-x64a.google.com [IPv6:2a00:1450:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9A9562F03B for ; Fri, 18 Nov 2022 09:23:11 -0800 (PST) Received: by mail-ej1-x64a.google.com with SMTP id sd31-20020a1709076e1f00b007ae63b8d66aso3376923ejc.3 for ; Fri, 18 Nov 2022 09:23:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=e+LcyMNkInxJbEkI4dZYVXRRy3OSinTohFLJ8BhSGEI=; b=Wl236N0EDKtBFLF3ZJNWeD3tjBamKSe4XEAfRsjqhhj+klve+os4bfTYg83EIPQ/4Q hp+cnUMvnITTbvKaNTXl07JdHoz+lGr+X/aXxb52r7wymAxIwAIlxeIHxKP3vsHuijiw eKuG/BOL2Jok/B9WT8pPYUhfJYFKk38jGlzqBHlvKuiGPUu5XDHXAr2LPnEu6Rloyt+W JCjDKRBdf8/ZZBamqF8rAC0KvR9N6tjia/WnhQgoFQE0X2V9opZjTcdwxnqaV7Xt8Hv1 q3fTPwUJeU8+AFSdVnASzguBS9QvQSpSqKPMg0TiRl+NXPG7ObOlcOmYUwi6HWl/BBfB dm2g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=e+LcyMNkInxJbEkI4dZYVXRRy3OSinTohFLJ8BhSGEI=; b=BzjThSeC2mL63ERPJbI8Fs212tyXV+Q5LFhfqm8sh+JrOqja+N63NchOHoGNoZS9Av 8rz+kF0gQ5aREU4hqjnzyH8iTR982qlzULn4ymD+FVJz60tpiMqbdjiijkMiM1eqxr8J gM7XF2F99IUz11MZPxRvGQB+lWx0ZEryHe0/zrwYnxX77+YkqUDYiOZYsWhY94lrRcHi 9u9MT5hhS7jDNjlb2sPaGh3tV9qeBxsi7HEg8YkzD9rzQK3TTjBaDi/4P2MPLZO35LSf k1jPHiE3WDFqpGjn3DxLuGmzGLSz46NpF1lm9lCPn9Yo8I3YFl9T7CXQrlqchI2cEDl2 KB1g== X-Gm-Message-State: ANoB5pli/miXVX9RHL+1xSKVFTFGDraUNy9G+3SUKXgSQcpDU+j9FwFt Se58acC7KecpBBruW4rnsIhzX6p1kWI= X-Google-Smtp-Source: AA0mqf6CBR8r/3p+/QPQA85y/BjrtndOTwIpc+lEGZVk9wmvkrbQpdqmtw1o1xb/PSRNT6TmR0gzHWc6jeY= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:ec10:bae8:fee8:751d]) (user=glider job=sendgmr) by 2002:a17:906:1188:b0:7b2:c594:2182 with SMTP id n8-20020a170906118800b007b2c5942182mr2246482eja.290.1668792190132; Fri, 18 Nov 2022 09:23:10 -0800 (PST) Date: Fri, 18 Nov 2022 18:23:05 +0100 Mime-Version: 1.0 X-Mailer: git-send-email 2.38.1.584.g0f3c55d4c2-goog Message-ID: <20221118172305.3321253-1-glider@google.com> Subject: [PATCH] x86: suppress KMSAN reports in arch_within_stack_frames() From: Alexander Potapenko To: glider@google.com Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, linux-kernel@vger.kernel.org, Eric Biggers Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org arch_within_stack_frames() performs stack walking and may confuse KMSAN by stepping on stale shadow values. To prevent false positive reports, disable KMSAN checks in this function. This fixes KMSAN's interoperability with CONFIG_HARDENED_USERCOPY. Link: https://github.com/google/kmsan/issues/89 Link: https://lore.kernel.org/lkml/Y3b9AAEKp2Vr3e6O@sol.localdomain/ Cc: Eric Biggers Signed-off-by: Alexander Potapenko --- arch/x86/include/asm/thread_info.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index f0cb881c1d690..f1cccba52eb97 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -163,7 +163,12 @@ struct thread_info { * GOOD_FRAME if within a frame * BAD_STACK if placed across a frame boundary (or outside stack) * NOT_STACK unable to determine (no frame pointers, etc) + * + * This function reads pointers from the stack and dereferences them. The + * pointers may not have their KMSAN shadow set up properly, which may result + * in false positive reports. Disable instrumentation to avoid those. */ +__no_kmsan_checks static inline int arch_within_stack_frames(const void * const stack, const void * const stackend, const void *obj, unsigned long len) -- 2.38.1.584.g0f3c55d4c2-goog