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Message-ID: <6d55e7af-4d68-2872-f407-268c3a4e95c8@quicinc.com>
Date:   Mon, 3 Apr 2023 12:53:54 -0700
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Subject: Re: [PATCH v4 1/2] check-uapi: Introduce check-uapi.sh
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To:     Masahiro Yamada <masahiroy@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        "Nicolas Schier" <nicolas@fjasle.eu>
CC:     <linux-kbuild@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-arm-msm@vger.kernel.org>,
        "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Bjorn Andersson <andersson@kernel.org>,
        Todd Kjos <tkjos@google.com>,
        Matthias Maennich <maennich@google.com>,
        Giuliano Procida <gprocida@google.com>,
        <kernel-team@android.com>, <libabigail@sourceware.org>,
        Jordan Crouse <jorcrous@amazon.com>,
        Trilok Soni <quic_tsoni@quicinc.com>,
        "Satya Durga Srinivasu Prabhala" <quic_satyap@quicinc.com>,
        Elliot Berman <quic_eberman@quicinc.com>,
        Guru Das Srinagesh <quic_gurus@quicinc.com>
References: <20230327174140.8169-1-quic_johmoo@quicinc.com>
 <20230327174140.8169-2-quic_johmoo@quicinc.com>
From:   John Moon <quic_johmoo@quicinc.com>
In-Reply-To: <20230327174140.8169-2-quic_johmoo@quicinc.com>
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On 3/27/2023 10:41 AM, John Moon wrote:
> While the kernel community has been good at maintaining backwards
> compatibility with kernel UAPIs, it would be helpful to have a tool
> to check if a commit introduces changes that break backwards
> compatibility.
> 
> To that end, introduce check-uapi.sh: a simple shell script that
> checks for changes to UAPI headers using libabigail.
> 
> libabigail is "a framework which aims at helping developers and
> software distributors to spot some ABI-related issues like interface
> incompatibility in ELF shared libraries by performing a static
> analysis of the ELF binaries at hand."
> 
> The script uses one of libabigail's tools, "abidiff", to compile the
> changed header before and after the commit to detect any changes.
> 
> abidiff "compares the ABI of two shared libraries in ELF format. It
> emits a meaningful report describing the differences between the two
> ABIs."
> 
> The script also includes the ability to check the compatibility of
> all UAPI headers across commits. This allows developers to inspect
> the stability of the UAPIs over time.
> 
> Signed-off-by: John Moon <quic_johmoo@quicinc.com>
> ---
>      - Refactored to exclusively check headers installed by make
>        headers_install. This simplified the code dramatically and removed
>        the need to perform complex git diffs.
>      - Removed the "-m" flag. Since we're checking all installed headers
>        every time, a flag to check only modified files didn't make sense.
>      - Added info message when usr/include/Makefile is not present that
>        it's likely because that file was only introduced in v5.3.
>      - Changed default behavior of log file. Now, the script will not
>        create a log file unless you pass "-l <file>".
>      - Simplified exit handler.
>      - Added -j $MAX_THREADS to make headers_install to improve speed.
>      - Cleaned up variable references.


Hi Masahiro, just a friendly reminder about this patch. I believe we've 
addressed all of your comments from previous reviews and we're looking 
forward to your feedback on this version.

Thanks so much!

- John