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: Tue, 7 May 2024 17:34:14 +0100 [thread overview]
Message-ID: <518dd1e3-e31a-41c3-b488-9b75a64b6c8a@arm.com> (raw)
In-Reply-To: <9e346b64-0a7c-4eb9-88c4-8fb6cf65b33f@nvidia.com>
On 07/05/2024 17:19, John Hubbard wrote:
> On 5/7/24 12:45 AM, Ryan Roberts wrote:
>> On 04/05/2024 05:43, John Hubbard wrote:
> ...
>> Hi John,
>>
>> I sent out a similar fix a couple of weeks ago, see [1]. I don't think it got
>> picked up though. It takes a slightly different approach, explicitly adding
>> -static-libsan (note no 'a') for clang, instead of relying on its default.
>>
>> And it just drops helpers.h from the makefile altogether, on the assumption that
>> it was a mistake; its just a header and shouldn't be compiled directly. I'm not
>> exactly sure what the benefit of adding it to LOCAL_HDRS is?
>
> Ah no, you must not drop headers.h. That's a mistake itself, because
> LOCAL_HDRS adds a Make dependency; that's its purpose. If you touch
> helpers.h it should cause a rebuild, which won't happen if you remove it
> from LOCAL_HDRS.
Ahh. I was under the impression that the compiler was configured to output the
list of dependencies for make to track (something like -M, from memory ?). Since
helpers.h is included from helpers.c I assumed it would be tracked like this - I
guess its not that simple?
Anyway, on the basis that LOCAL_HDRS is the right way to do this, let's go with
your version and drop mine:
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
>
> The way it works is that lib.mk adds $(LOCAL_HDRS) to the dependencies list,
> but then filters precisely that same set *out* of the list that it provides
> to the compile invocation.
>
> The other way to implement this requirement of "some things need to be
> Make dependencies, and some need to be both dependencies and compilation
> inputs", is to add everything to the dependency list, but then use a
> separate list of files to pass to the compiler. For an example of that,
> see $(EXTRA_FILES) in patch 1/7 [1] of my selftests/x86 cleanup.
>
> [1] https://lore.kernel.org/all/20240503030214.86681-2-jhubbard@nvidia.com/
>
> thanks,
> John Hubbard
>
>>
>> [1]
>> https://lore.kernel.org/linux-kselftest/20240417160740.2019530-1-ryan.roberts@arm.com/
>>
>> Thanks,
>> Ryan
>>
>>
>>> ---
>>> tools/testing/selftests/openat2/Makefile | 14 ++++++++++++--
>>> 1 file changed, 12 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/tools/testing/selftests/openat2/Makefile
>>> b/tools/testing/selftests/openat2/Makefile
>>> index 254d676a2689..185dc76ebb5f 100644
>>> --- a/tools/testing/selftests/openat2/Makefile
>>> +++ b/tools/testing/selftests/openat2/Makefile
>>> @@ -1,8 +1,18 @@
>>> # SPDX-License-Identifier: GPL-2.0-or-later
>>> -CFLAGS += -Wall -O2 -g -fsanitize=address -fsanitize=undefined
>>> -static-libasan
>>> +CFLAGS += -Wall -O2 -g -fsanitize=address -fsanitize=undefined
>>> TEST_GEN_PROGS := openat2_test resolve_test rename_attack_test
>>> +# gcc requires -static-libasan in order to ensure that Address Sanitizer's
>>> +# library is the first one loaded. However, clang already statically links the
>>> +# Address Sanitizer if -fsanitize is specified. Therefore, simply omit
>>> +# -static-libasan for clang builds.
>>> +ifeq ($(LLVM),)
>>> + CFLAGS += -static-libasan
>>> +endif
>>> +
>>> +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
>>
>
> thanks,
next prev parent reply other threads:[~2024-05-07 16:34 UTC|newest]
Thread overview: 13+ 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 [this message]
2024-05-07 16:47 ` John Hubbard
2024-05-07 16:56 ` Ryan Roberts
2024-05-10 11:52 ` Ryan Roberts
2024-05-10 17:56 ` John Hubbard
2024-05-10 18:22 ` John Hubbard
2024-05-11 17:19 ` Ryan Roberts
2024-05-30 3:58 ` Muhammad Usama Anjum
2024-05-30 4:35 ` John Hubbard
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