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Date:   Mon, 6 May 2019 22:57:37 +0100
From:   Qais Yousef <qais.yousef@arm.com>
To:     Joel Fernandes <joel@joelfernandes.org>
Cc:     Will Deacon <will.deacon@arm.com>, linux-kernel@vger.kernel.org,
        Michal Gregorczyk <michalgr@live.com>,
        Adrian Ratiu <adrian.ratiu@collabora.com>,
        Mohammad Husain <russoue@gmail.com>,
        Srinivas Ramana <sramana@codeaurora.org>,
        duyuchao <yuchao.du@unisoc.com>,
        Manjo Raja Rao <linux@manojrajarao.com>,
        Karim Yaghmour <karim.yaghmour@opersys.com>,
        Tamir Carmeli <carmeli.tamir@gmail.com>,
        Yonghong Song <yhs@fb.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Brendan Gregg <brendan.d.gregg@gmail.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Peter Ziljstra <peterz@infradead.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Kees Cook <keescook@chromium.org>, kernel-team@android.com,
        Daniel Borkmann <daniel@iogearbox.net>,
        Ingo Molnar <mingo@redhat.com>, netdev@vger.kernel.org,
        Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH RFC] bpf: Add support for reading user pointers
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On 05/06/19 16:58, Joel Fernandes wrote:
> > If you're trying to dereference a pointer to userspace using
> > probe_kernel_read(), that clearly isn't going to work.
> 
> Ok. Thanks for confirming as well. The existing code has this bug and these
> patches fix it.

5.1-rc7 and 4.9.173 stable both managed to read the path in do_sys_open() on my
Juno-r2 board using the defconfig in the tree.

--
Qais Yousef