From: Ryan Roberts <ryan.roberts@arm.com>
To: John Hubbard <jhubbard@nvidia.com>, Shuah Khan <shuah@kernel.org>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
"Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>,
"Maciej Wieczor-Retman" <maciej.wieczor-retman@intel.com>,
"Christian Brauner" <brauner@kernel.org>,
"Muhammad Usama Anjum" <usama.anjum@collabora.com>,
"Alexey Gladkov" <legion@kernel.org>,
"Valentin Obst" <kernel@valentinobst.de>,
linux-kselftest@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>,
llvm@lists.linux.dev
Subject: Re: [PATCH 1/2] selftests/openat2: fix clang build failures: -static-libasan, LOCAL_HDRS
Date: Fri, 10 May 2024 12:52:18 +0100 [thread overview]
Message-ID: <c406383d-e08a-4a12-9e25-1c987b0d678f@arm.com> (raw)
In-Reply-To: <20240504044336.14411-1-jhubbard@nvidia.com>
On 04/05/2024 05:43, John Hubbard wrote:
> When building with clang via:
>
> make LLVM=1 -C tools/testing/selftests
>
> two distinct failures occur:
>
> 1) gcc requires -static-libasan in order to ensure that Address
> Sanitizer's library is the first one loaded. However, this leads to
> build failures on clang, when building via:
>
> make LLVM=1 -C tools/testing/selftests
>
> However, clang already does the right thing by default: it statically
> links the Address Sanitizer if -fsanitize is specified. Therefore, fix
> this by simply omitting -static-libasan for clang builds. And leave
> behind a comment, because the whole reason for static linking might not
> be obvious.
>
> 2) clang won't accept invocations of this form, but gcc will:
>
> $(CC) file1.c header2.h
>
> Fix this by using selftests/lib.mk facilities for tracking local header
> file dependencies: add them to LOCAL_HDRS, leaving only the .c files to
> be passed to the compiler.
>
> Cc: Ryan Roberts <ryan.roberts@arm.com>
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
> ---
> tools/testing/selftests/openat2/Makefile | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/openat2/Makefile b/tools/testing/selftests/openat2/Makefile
> index 254d676a2689..185dc76ebb5f 100644
> --- a/tools/testing/selftests/openat2/Makefile
> +++ b/tools/testing/selftests/openat2/Makefile
> @@ -1,8 +1,18 @@
> # SPDX-License-Identifier: GPL-2.0-or-later
>
> -CFLAGS += -Wall -O2 -g -fsanitize=address -fsanitize=undefined -static-libasan
> +CFLAGS += -Wall -O2 -g -fsanitize=address -fsanitize=undefined
> TEST_GEN_PROGS := openat2_test resolve_test rename_attack_test
>
> +# gcc requires -static-libasan in order to ensure that Address Sanitizer's
> +# library is the first one loaded. However, clang already statically links the
> +# Address Sanitizer if -fsanitize is specified. Therefore, simply omit
> +# -static-libasan for clang builds.
> +ifeq ($(LLVM),)
> + CFLAGS += -static-libasan
> +endif
It just occured to me that the bug report I was fixing with my attempt was
invoking make like this (see [1]):
# tools/testing/selftests/fchmodat2$ make CC=clang
# tools/testing/selftests/openat2$ make CC=clang
So LLVM is not set in this case. Perhaps my approach [2] (suggested by Arnd) of
using cc-option is more robust? (cc-option is alredy used by other selftests).
[1] https://lore.kernel.org/all/202404141807.LgsqXPY5-lkp@intel.com/
[2]
https://lore.kernel.org/linux-kselftest/20240417160740.2019530-1-ryan.roberts@arm.com/
> +
> +LOCAL_HDRS += helpers.h
> +
> include ../lib.mk
>
> -$(TEST_GEN_PROGS): helpers.c helpers.h
> +$(TEST_GEN_PROGS): helpers.c
>
> base-commit: ddb4c3f25b7b95df3d6932db0b379d768a6ebdf7
> prerequisite-patch-id: b901ece2a5b78503e2fb5480f20e304d36a0ea27
next prev parent reply other threads:[~2024-05-10 11:52 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-04 4:43 [PATCH 1/2] selftests/openat2: fix clang build failures: -static-libasan, LOCAL_HDRS John Hubbard
2024-05-04 4:43 ` [PATCH 2/2] selftests/fchmodat2: fix clang build failure due to -static-libasan John Hubbard
2024-05-07 7:45 ` [PATCH 1/2] selftests/openat2: fix clang build failures: -static-libasan, LOCAL_HDRS Ryan Roberts
2024-05-07 16:19 ` John Hubbard
2024-05-07 16:34 ` Ryan Roberts
2024-05-07 16:47 ` John Hubbard
2024-05-07 16:56 ` Ryan Roberts
2024-05-10 11:52 ` Ryan Roberts [this message]
2024-05-10 17:56 ` John Hubbard
2024-05-10 18:22 ` John Hubbard
2024-05-11 17:19 ` Ryan Roberts
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