Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Thu, 6 Apr 2023 15:58:12 +0200
From:   Cyril Hrubis <chrubis@suse.cz>
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     Petr Vorel <pvorel@suse.cz>,
        Naresh Kamboju <naresh.kamboju@linaro.org>,
        open list <linux-kernel@vger.kernel.org>,
        LTP List <ltp@lists.linux.it>, llvm@lists.linux.dev,
        Nathan Chancellor <nathan@kernel.org>,
        Anders Roxell <anders.roxell@linaro.org>,
        Daniel =?iso-8859-1?Q?D=EDaz?= <daniel.diaz@linaro.org>,
        Benjamin Copeland <ben.copeland@linaro.org>,
        Tudor Cretu <tudor.cretu@arm.com>
Subject: Re: LTP: list of failures on 32bit and compat mode
Message-ID: <ZC7P9BgW1CTFAMjB@yuki>
References: <CA+G9fYtVXsKSbdxcTNiLc8oYRTBOZzWNQRF92daLE58NPbOkFg@mail.gmail.com>
 <96b67ae8-98dd-40fe-9dde-302e09d12551@app.fastmail.com>
 <20230406105646.GB1545779@pevik>
 <7234b8ab-db5c-4f4a-bb9e-ddef9f1a50d3@app.fastmail.com>
 <20230406124812.GA1589248@pevik>
 <3c2ba6f9-bea1-4510-8fbb-6521fab74a9d@app.fastmail.com>
 <20230406131755.GA1608262@pevik>
 <c2a6d31f-173b-4d08-b377-e31748f33443@app.fastmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <c2a6d31f-173b-4d08-b377-e31748f33443@app.fastmail.com>
Precedence: bulk

Hi!
> > Thanks! I've just searched in musl as well, because it didn't make sense to me
> > it'd be a code for LTP.
> >
> > "to catch the fault on ltp" I wonder if it's not actually musl bug.
> 
> No, musl is fine here. The problem is that ltp passes an invalid pointer,
> expecting to get -EFAULT from the kernel when that faults in
> copy_to_user().
> 
> There is nothing wrong with musl sanitizing the data behind that
> pointer, but then you get a signal instead of the EFAULT error.

That's actually quite common, usually we fix that by running the test in
a child and treating SEGFAULT as a PASS.

-- 
Cyril Hrubis
chrubis@suse.cz