Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Tue, 30 Mar 2021 15:40:37 +0200
From:   Greg KH <greg@kroah.com>
To:     Fawad Lateef <fawadlateef@gmail.com>
Cc:     Arnd Bergmann <arnd@kernel.org>,
        kernelnewbies <kernelnewbies@kernelnewbies.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Compiling kernel-3.4.xxx with gcc-9.x. Need some help.
Message-ID: <YGMqVc+DyVyT9DtW@kroah.com>
References: <CAGgoGu77PEEAJped5bnw4q8rFeDMebL92YWGDGFfNp_ZAnpJ8Q@mail.gmail.com>
 <YGFeQUuAaKgeaqCA@kroah.com>
 <CAGgoGu76FOJd74oVgnu5Sa3GKaHHyLTH+=hP+mLGzS+79Z26fA@mail.gmail.com>
 <CAK8P3a24aFvCUeZiDE6jCTKm0hrPVc34sNYOPpZJkh_5HpgDSw@mail.gmail.com>
 <CAGgoGu5xT6sADCpj7J7tJMfsw1WU4BA=3YB8SGS-+kf+P4xyNw@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAGgoGu5xT6sADCpj7J7tJMfsw1WU4BA=3YB8SGS-+kf+P4xyNw@mail.gmail.com>
Precedence: bulk

On Tue, Mar 30, 2021 at 03:23:10PM +0200, Fawad Lateef wrote:
> So can I still use kernel-3.4 compiled with gcc-5.5, and boot full
> user-space with gcc-9.1?

Yes, of course.

> I was expecting it to be possible but might not work due to
> incompatibility? As I know that when I tried to compile buildroot-2019
> (with latest version of openssl and others) it needs kernel headers
> and then I likely can't use 3.4 kernel.

buildroot might be different, as that is how you are building your whole
system, but there is no dependency on the kernel and userspace to use
the same version of the compiler.  Otherwise everyone would have to
rebuild the world for every time they updated their kernel, this isn't
the BSDs :)

thanks,

greg k-h