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 AA60EC19F2A for ; Mon, 8 Aug 2022 01:31:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241867AbiHHBbj (ORCPT ); Sun, 7 Aug 2022 21:31:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57174 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241853AbiHHBbf (ORCPT ); Sun, 7 Aug 2022 21:31:35 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 985E255A1; Sun, 7 Aug 2022 18:31:34 -0700 (PDT) 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 dfw.source.kernel.org (Postfix) with ESMTPS id 1E8E060DE0; Mon, 8 Aug 2022 01:31:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 80CF6C433C1; Mon, 8 Aug 2022 01:31:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1659922293; bh=GUDAZS/+eUIcCGBBfhfW4KeWzTJXZXRYQZKOZTAGzHc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m8HMRgg9xn7XTiW5ZK9p3LVXQHz5ppFZfw3tE+n+KEn1w0xXZBg3DsZvIWEfnJFj7 dt3eIcQk3Ty4JnMU3IraRzCTfjv0QDbuaY8GzS1NOj10iLGuOhgOOKGUyDPYVPSMOx f/WuSeB556oxfSFWOBz/Hlw9vrHlkWy092IklG/aV4w7IXIY8BiEe6kGdatCGcg7VB aWuOJI63cgRwNhxJbhjlkWwAbmYNjusomSl68FElDCeSSyxrVW4WBk2olPDGwGz13Z VJgsEk/G18/lTwZ9suRoGFlEGqTHex2AiCdyJ6hjdmlpTKNuF8xl90sDOjdg9+x7B6 DYD5HQ0wpDQmw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Andrey Konovalov , Mark Rutland , Will Deacon , Sasha Levin , catalin.marinas@arm.com, broonie@kernel.org, keescook@chromium.org, joey.gouly@arm.com, andreyknvl@gmail.com, ardb@kernel.org, masahiroy@kernel.org, kaleshsingh@google.com, madvenka@linux.microsoft.com, mhiramat@kernel.org, maz@kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 5.19 03/58] arm64: kasan: do not instrument stacktrace.c Date: Sun, 7 Aug 2022 21:30:21 -0400 Message-Id: <20220808013118.313965-3-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220808013118.313965-1-sashal@kernel.org> References: <20220808013118.313965-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andrey Konovalov [ Upstream commit 802b91118d11227b527153849ea761b280691373 ] Disable KASAN instrumentation of arch/arm64/kernel/stacktrace.c. This speeds up Generic KASAN by 5-20%. As a side-effect, KASAN is now unable to detect bugs in the stack trace collection code. This is taken as an acceptable downside. Also replace READ_ONCE_NOCHECK() with READ_ONCE() in stacktrace.c. As the file is now not instrumented, there is no need to use the NOCHECK version of READ_ONCE(). Suggested-by: Mark Rutland Acked-by: Mark Rutland Signed-off-by: Andrey Konovalov Link: https://lore.kernel.org/r/c4c944a2a905e949760fbeb29258185087171708.1653317461.git.andreyknvl@google.com Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/kernel/Makefile | 5 +++++ arch/arm64/kernel/stacktrace.c | 4 ++-- 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index fa7981d0d917..7075a9c6a4a6 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -14,6 +14,11 @@ CFLAGS_REMOVE_return_address.o = $(CC_FLAGS_FTRACE) CFLAGS_REMOVE_syscall.o = -fstack-protector -fstack-protector-strong CFLAGS_syscall.o += -fno-stack-protector +# When KASAN is enabled, a stack trace is recorded for every alloc/free, which +# can significantly impact performance. Avoid instrumenting the stack trace +# collection code to minimize this impact. +KASAN_SANITIZE_stacktrace.o := n + # It's not safe to invoke KCOV when portions of the kernel environment aren't # available or are out-of-sync with HW state. Since `noinstr` doesn't always # inhibit KCOV instrumentation, disable it for the entire compilation unit. diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 0467cb79f080..c246e8d9f95b 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -124,8 +124,8 @@ static int notrace unwind_next(struct task_struct *tsk, * Record this frame record's values and location. The prev_fp and * prev_type are only meaningful to the next unwind_next() invocation. */ - state->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp)); - state->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8)); + state->fp = READ_ONCE(*(unsigned long *)(fp)); + state->pc = READ_ONCE(*(unsigned long *)(fp + 8)); state->prev_fp = fp; state->prev_type = info.type; -- 2.35.1