linux-kernel - Re: [PATCH v3 13/23] platform/chrome: cros_ec: don't allocate `din` and `dout` in cros_ec

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Date:   Thu, 9 Jun 2022 05:09:03 +0000
From:   Tzung-Bi Shih <tzungbi@...nel.org>
To:     Guenter Roeck <groeck@...gle.com>
Cc:     Benson Leung <bleung@...omium.org>,
        Guenter Roeck <groeck@...omium.org>,
        "open list:CHROME HARDWARE PLATFORM SUPPORT" 
        <chrome-platform@...ts.linux.dev>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 13/23] platform/chrome: cros_ec: don't allocate `din`
 and `dout` in cros_ec_register()

On Wed, Jun 08, 2022 at 09:15:56AM -0700, Guenter Roeck wrote:
> On Wed, Jun 8, 2022 at 4:08 AM Tzung-Bi Shih <tzungbi@...nel.org> wrote:
> >
> > Don't allocate `din` and `dout` in cros_ec_register() as they will be
> > allocated soon in cros_ec_query_all().

Pardon me, I should test them earlier.

I misunderstood.  The patch will cause kernel crash (NULL dereference)
because cros_ec_query_all() relies on `din` and `dout` for getting protocol
info and then it reallocates the buffers according to the info later.

I think we should just leave them as they are.  Will drop this patch and next
patch ([v3,14/23] platform/chrome: don't use devm variants for `din` and
`dout`).