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Date:   Fri, 21 Aug 2020 12:19:03 +0200
From:   peterz@infradead.org
To:     Daniel Thompson <daniel.thompson@linaro.org>
Cc:     x86@kernel.org, linux-kernel@vger.kernel.org,
        Kyle Huey <me@kylehuey.com>,
        Alexandre Chartre <alexandre.chartre@oracle.com>,
        Robert O'Callahan <rocallahan@gmail.com>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Frederic Weisbecker <frederic@kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Petr Mladek <pmladek@suse.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Joel Fernandes <joel@joelfernandes.org>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Juergen Gross <jgross@suse.com>,
        Brian Gerst <brgerst@gmail.com>,
        Andy Lutomirski <luto@kernel.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>
Subject: Re: [RFC][PATCH 4/7] x86/debug: Move historical SYSENTER junk into
 exc_debug_kernel()
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 <20200820104905.294802764@infradead.org>
 <20200820152828.tvluka3lvmzof5xt@holly.lan>
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On Thu, Aug 20, 2020 at 04:28:28PM +0100, Daniel Thompson wrote:

> Specifically I've entered the kdb in pretty much the simplest way
> possible: a direct call to kgdb_breakpoint() from a task context. I
> generate a backtrace to illustrate this, just to give you a better
> understanding of what might be happening) and then ran the single step.


> + make -C .. O=$PWD x86_64_defconfig
> + ../scripts/config --enable RUNTIME_TESTING_MENU
> + ../scripts/config --enable DEBUG_INFO --enable DEBUG_FS --enable KALLSYMS_ALL --enable MAGIC_SYSRQ --enable KGDB --enable KGDB_TESTS --enable KGDB_KDB --enable KDB_KEYBOARD --enable LKDTM
> + ../scripts/config --enable PROVE_LOCKING --enable DEBUG_ATOMIC_SLEEP
> + make olddefconfig


That asked me about a kgdb boottime selftest, which I figured was a good
idea, but even without my patches that seems to fail, and fail so that
it doesn't boot :/

> # echo g > /proc/sysrq-trigger

OK, I think I got that working with the latest set.

Thanks!