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Date:   Tue, 25 Jan 2022 15:37:11 +0100
From:   Borislav Petkov <bp@alien8.de>
To:     Eliav Farber <farbere@amazon.com>
Cc:     mchehab@kernel.org, linux-edac@vger.kernel.org,
        linux-kernel@vger.kernel.org, ronenk@amazon.com, talel@amazon.com,
        hhhawa@amazon.com, jonnyc@amazon.com, hanochu@amazon.com
Subject: Re: [PATCH 1/4] EDAC: Fix calculation of returned address and next
 offset in edac_align_ptr()
Message-ID: <YfALFy7LGGIOS2Fv@zn.tnic>
References: <20220113100622.12783-1-farbere@amazon.com>
 <20220113100622.12783-2-farbere@amazon.com>
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On Thu, Jan 13, 2022 at 10:06:19AM +0000, Eliav Farber wrote:
> Do alignment logic properly and use 'ptr' for calculating the remainder
> of the alignment.
> 
> This became an issue because 'struct edac_mc_layer' has a size that is
> not zero modulo eight, and the next offset that was prepared for the
> private-data was unaligned, causing an alignment exception.

How exactly did this "become an issue"?

I'm asking because I have been hearing about weird bugs with that
pointer alignment contraption and have never managed to reproduce them
myself or hear a proper explanation from people.

And that thing is an abomination, frankly, and I'd like to get rid of it
but maybe some other time...

So, please explain more verbosely, a specific example or how I could
reproduce it, would be even better.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette