From nobody Sun Feb 8 13:10:49 2026 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 40B87CD13D8 for ; Mon, 18 Sep 2023 10:53:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238234AbjIRKxB (ORCPT ); Mon, 18 Sep 2023 06:53:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45766 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236692AbjIRKwq (ORCPT ); Mon, 18 Sep 2023 06:52:46 -0400 Received: from smtp2.axis.com (smtp2.axis.com [195.60.68.18]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF258A1 for ; Mon, 18 Sep 2023 03:52:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=axis.com; q=dns/txt; s=axis-central1; t=1695034360; x=1726570360; h=from:date:subject:mime-version:content-transfer-encoding: message-id:to:cc; bh=bOsEzjVQKBPn7rGdrNw3l2iC/L1VtxB+euAZfU+U4zs=; b=K4y04qXC/1oq7GFlhMJEo/u48oSIj0wG0qXIrBm4gnU9Uxs/l3OQBbII Bk5+N8iLufUmt0Fuh4d8EAX32u4DS3JQW02kYoI3w8XTNEpXIUQGXboS3 qt5AiVNH3b69NFdYvi6mWv4sJOhOWmyHAFrvzLXFCYn4EOGwMHcjEonFe 8GhRe1C91Mq2Rwv9WgHARidsC8TomLdfPxjZ2YmsG9V3OPmlHzhm26uXW rQlaXP9UnRgEUaIbRuo/P61kgZjp/06DZNOI83pZp9nWpj2MgHl8Dk7TT dKjiiZkp4n6H/WQZglxfq6HHG2+2Wj34Xt8Yl0yOoTu1r5bHbhURkGANo w==; From: Vincent Whitchurch Date: Mon, 18 Sep 2023 12:52:34 +0200 Subject: [PATCH v3] x86: Fix build of UML with KASAN MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-ID: <20230918-uml-kasan-v3-1-7ad6db477df6@axis.com> X-B4-Tracking: v=1; b=H4sIAPErCGUC/22Nyw7CIBBFf6VhLYZXTXHlfxgXFAZLtNCAkpqm/ y50YxdmVudmzr0LShAdJHRuFhQhu+SCL8APDdKD8nfAzhRGjDBOTkTi9/jED5WUx4xLZozQvGs 7VP57lQD3UXk9VMOGwGo8RbBu3iaut8KDS68QP9tipjX9V54ppri1SndGEGmEvajZpaMOI6olm f1ESdu9yIoIlpezwlIhduK6rl9voZLC8QAAAA== To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , , "H. Peter Anvin" , Frederic Weisbecker , "Rafael J. Wysocki" , Peter Zijlstra CC: Richard Weinberger , Anton Ivanov , Johannes Berg , , Andrey Ryabinin , Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , , , , Vincent Whitchurch X-Mailer: b4 0.12.3 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Building UML with KASAN fails since commit 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functions") with the following errors: $ tools/testing/kunit/kunit.py run --kconfig_add CONFIG_KASAN=3Dy ... ld: mm/kasan/shadow.o: in function `memset': shadow.c:(.text+0x40): multiple definition of `memset'; arch/x86/lib/memset_64.o:(.noinstr.text+0x0): first defined here ld: mm/kasan/shadow.o: in function `memmove': shadow.c:(.text+0x90): multiple definition of `memmove'; arch/x86/lib/memmove_64.o:(.noinstr.text+0x0): first defined here ld: mm/kasan/shadow.o: in function `memcpy': shadow.c:(.text+0x110): multiple definition of `memcpy'; arch/x86/lib/memcpy_64.o:(.noinstr.text+0x0): first defined here UML does not use GENERIC_ENTRY and is still supposed to be allowed to override the mem*() functions, so use weak aliases in that case. Fixes: 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functio= ns") Signed-off-by: Vincent Whitchurch --- Changes in v3: - Add SYM_FUNC_ALIAS_MEMFUNC() macro to avoid ifdefs in multiple places. - Link to v2: https://lore.kernel.org/r/20230915-uml-kasan-v2-1-ef3f3ff4f14= 4@axis.com Changes in v2: - Use CONFIG_UML instead of CONFIG_GENERIC_ENTRY. - Link to v1: https://lore.kernel.org/r/20230609-uml-kasan-v1-1-5fac8d409d4= f@axis.com --- arch/x86/include/asm/linkage.h | 7 +++++++ arch/x86/lib/memcpy_64.S | 2 +- arch/x86/lib/memmove_64.S | 2 +- arch/x86/lib/memset_64.S | 2 +- 4 files changed, 10 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/linkage.h b/arch/x86/include/asm/linkage.h index 97a3de7892d3..32cdf1e92cfb 100644 --- a/arch/x86/include/asm/linkage.h +++ b/arch/x86/include/asm/linkage.h @@ -97,6 +97,13 @@ CFI_POST_PADDING \ SYM_FUNC_END(__cfi_##name) =20 +/* UML needs to be able to override memcpy() and friends for KASAN. */ +#ifdef CONFIG_UML +#define SYM_FUNC_ALIAS_MEMFUNC SYM_FUNC_ALIAS_WEAK +#else +#define SYM_FUNC_ALIAS_MEMFUNC SYM_FUNC_ALIAS +#endif + /* SYM_TYPED_FUNC_START -- use for indirectly called globals, w/ CFI type = */ #define SYM_TYPED_FUNC_START(name) \ SYM_TYPED_START(name, SYM_L_GLOBAL, SYM_F_ALIGN) \ diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S index 8f95fb267caa..76697df8dfd5 100644 --- a/arch/x86/lib/memcpy_64.S +++ b/arch/x86/lib/memcpy_64.S @@ -40,7 +40,7 @@ SYM_TYPED_FUNC_START(__memcpy) SYM_FUNC_END(__memcpy) EXPORT_SYMBOL(__memcpy) =20 -SYM_FUNC_ALIAS(memcpy, __memcpy) +SYM_FUNC_ALIAS_MEMFUNC(memcpy, __memcpy) EXPORT_SYMBOL(memcpy) =20 SYM_FUNC_START_LOCAL(memcpy_orig) diff --git a/arch/x86/lib/memmove_64.S b/arch/x86/lib/memmove_64.S index 0559b206fb11..ccdf3a597045 100644 --- a/arch/x86/lib/memmove_64.S +++ b/arch/x86/lib/memmove_64.S @@ -212,5 +212,5 @@ SYM_FUNC_START(__memmove) SYM_FUNC_END(__memmove) EXPORT_SYMBOL(__memmove) =20 -SYM_FUNC_ALIAS(memmove, __memmove) +SYM_FUNC_ALIAS_MEMFUNC(memmove, __memmove) EXPORT_SYMBOL(memmove) diff --git a/arch/x86/lib/memset_64.S b/arch/x86/lib/memset_64.S index 7c59a704c458..3d818b849ec6 100644 --- a/arch/x86/lib/memset_64.S +++ b/arch/x86/lib/memset_64.S @@ -40,7 +40,7 @@ SYM_FUNC_START(__memset) SYM_FUNC_END(__memset) EXPORT_SYMBOL(__memset) =20 -SYM_FUNC_ALIAS(memset, __memset) +SYM_FUNC_ALIAS_MEMFUNC(memset, __memset) EXPORT_SYMBOL(memset) =20 SYM_FUNC_START_LOCAL(memset_orig) --- base-commit: 0bb80ecc33a8fb5a682236443c1e740d5c917d1d change-id: 20230609-uml-kasan-2392dd4c3858 Best regards, --=20 Vincent Whitchurch