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From:   ebiederm@xmission.com (Eric W. Biederman)
To:     Ingo Molnar <mingo@kernel.org>
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        Arnd Bergmann <arnd@arndb.de>,
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Date:   Mon, 17 May 2021 10:29:39 -0500
In-Reply-To: <YKDMWXj2YDkDy1DG@gmail.com> (Ingo Molnar's message of "Sun, 16
        May 2021 09:40:09 +0200")
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User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux)
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Subject: Re: [GIT PULL] siginfo: ABI fixes for v5.13-rc2
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Ingo Molnar <mingo@kernel.org> writes:

> * Eric W. Biederman <ebiederm@xmission.com> wrote:
>
>> Looking deeper it was discovered that si_trapno is used for only
>> a few select signals on alpha and sparc, and that none of the
>> other _sigfault fields past si_addr are used at all.  Which means
>> technically no regression on alpha and sparc.
>
> If there's no functional regression on any platform, could much of this 
> wait until v5.14, or do we want some of these cleanups right now?
>
> The fixes seem to be for long-existing bugs, not fresh regressions, AFAICS. 
> The asserts & cleanups are useful, but not regression fixes.
>
> I.e. this is a bit scary:

The new ABI for SIGTRAP TRAP perf that came in the merge window is
broken and wrong.  We need to revert/disable the new SIGTRAP TRAP_PERF
or have a fix before v5.13.

The issue is old crap getting in the way of a new addition.  I think I
might see a smaller code change on how to get to something compatible
with this.

>>  32 files changed, 377 insertions(+), 163 deletions(-)
>
> at -rc2 time.

The additions are all tests to make certain everything is fine.
The actual code change without the assertions (tests) is essentially
a wash.

Eric