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From:   Alistair Strachan <astrachan@google.com>
Date:   Fri, 14 Dec 2018 14:24:27 -0800
Message-ID: <CANDihLFgOmkumZ-W4i=5oOb1Zu+BHJz8M-WphYYyAdb9jYdL+g@mail.gmail.com>
Subject: Re: Unwinding regression with 379d98ddf413 ("x86: vdso: Use $LD
 instead of $CC to link")
To:     labbott@redhat.com
Cc:     luto@kernel.org, tglx@linutronix.de, hpa@zytor.com,
        kernel-team@android.com, joel@joelfernandes.org, x86@kernel.org,
        linux-kernel@vger.kernel.org, fweimer@redhat.com,
        carlos@redhat.com, hjl.tools@gmail.com
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Hi Laura,

On Fri, Dec 14, 2018 at 1:48 PM Laura Abbott <labbott@redhat.com> wrote:
> Hi,
>
> There are two reports of a regression with unwinding with
> 379d98ddf413 ("x86: vdso: Use $LD instead of $CC to link")
>
> https://bugzilla.kernel.org/show_bug.cgi?id=201741
> https://bugzilla.redhat.com/show_bug.cgi?id=1659295
>
> It looks like the unwinding information has been
> stripped out. Any ideas?

Sorry about this. I missed a critical flag (--eh-frame-hdr) that gcc
specifies implicitly when converting the Makefile to invoke ld
directly. This went unnoticed because the linking of vmlinux (which
also uses ld directly) does not need this information, so it does not
specify the flag. Sending a verified fix now.

> Thanks,
> Laura