linux-kernel - Re: [PATCH rdma-next 1/4] gcov: Open-code kmemdup() to work correctly with kernel and user space pointers

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Message-ID: <CAHk-=whbijeSdSvx-Xcr0DPMj0BiwhJ+uiNnDSVZcr_h_kg7UA@mail.gmail.com>
Date:   Wed, 2 Sep 2020 12:04:55 -0700
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Leon Romanovsky <leon@...nel.org>
Cc:     Peter Oberparleiter <oberpar@...ux.ibm.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Colin Ian King <colin.king@...onical.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH rdma-next 1/4] gcov: Open-code kmemdup() to work correctly
 with kernel and user space pointers

On Wed, Sep 2, 2020 at 11:44 AM Leon Romanovsky <leon@...nel.org> wrote:
>
> I already don't remember why, but copy_from_user() caused to second flow
> of gcov_info_dup() through gcov_event() to generate another set of warnings.
>
> As a summary, I have a workaround, but I don't know why it works and not
> proud about it.

Ok, it does sound like "let's just disable gcov for the affected
compilers" is the way to go.

If/when somebody figures out exactly what's up and how to work around
it properly, maybe we can then revisit the issue.

Thanks,

                Linus