From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <frederic@kernel.org>,
LKML <linux-kernel@vger.kernel.org>, Mel Gorman <mgorman@suse.de>,
Michal Hocko <mhocko@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E . McKenney" <paulmck@kernel.org>,
Ingo Molnar <mingo@redhat.com>, Michal Hocko <mhocko@suse.com>,
rostedt@goodmis.org, jbaron@akamai.com, ardb@kernel.org
Subject: Re: [RFC PATCH 6/8] preempt/dynamic: Provide preempt_schedule[_notrace]() static calls
Date: Mon, 25 Jan 2021 17:40:39 -0600 [thread overview]
Message-ID: <20210125234039.mb5fvhyzzoujajhm@treble> (raw)
In-Reply-To: <20210122165226.GD16371@worktop.programming.kicks-ass.net>
On Fri, Jan 22, 2021 at 05:52:26PM +0100, Peter Zijlstra wrote:
> On Mon, Jan 18, 2021 at 03:12:21PM +0100, Frederic Weisbecker wrote:
> > +#ifdef CONFIG_PREEMPT_DYNAMIC
> > +DEFINE_STATIC_CALL(preempt_schedule, __preempt_schedule_func());
> > +EXPORT_STATIC_CALL(preempt_schedule);
> > +#endif
>
> > +#ifdef CONFIG_PREEMPT_DYNAMIC
> > +DEFINE_STATIC_CALL(preempt_schedule_notrace, __preempt_schedule_notrace_func());
> > +EXPORT_STATIC_CALL(preempt_schedule_notrace);
> > +#endif
>
> So one of the things I hates most of this is that is allows 'random'
> modules to hijack the preemption by rewriting these callsites. Once you
> export the key, we've lost.
>
> I've tried a number of things, but this is the only one I could come up
> with that actually stands a chance against malicious modules (vbox and
> the like).
>
> It's somewhat elaborate, but afaict it actually works.
What about this hopefully abuse-proof idea which has less code, less
complexity, no registration, no new data structures, no COC defiance.
Add a writable-by-modules bit to the key struct, which can be set when
you define the key. Enforce it in __static_call_update() with a call to
__builtin_return_address(0). WARN when the caller's text isn't in the
kernel proper and the flag isn't set.
Hm?
--
Josh
next prev parent reply other threads:[~2021-01-25 23:44 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-18 14:12 [RFC PATCH 0/7] preempt: Tune preemption flavour on boot v4 Frederic Weisbecker
2021-01-18 14:12 ` [RFC PATCH 1/8] static_call/x86: Add __static_call_return0() Frederic Weisbecker
2021-02-08 12:00 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-02-17 13:17 ` tip-bot2 for Peter Zijlstra
2021-01-18 14:12 ` [RFC PATCH 2/8] static_call: Provide DEFINE_STATIC_CALL_RET0() Frederic Weisbecker
2021-02-08 12:00 ` [tip: sched/core] " tip-bot2 for Frederic Weisbecker
2021-02-17 13:17 ` tip-bot2 for Frederic Weisbecker
2021-01-18 14:12 ` [RFC PATCH 3/8] static_call: Pull some static_call declarations to the type headers Frederic Weisbecker
2021-01-19 10:46 ` Jürgen Groß
2021-02-08 12:00 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-02-17 13:17 ` tip-bot2 for Peter Zijlstra
2021-01-18 14:12 ` [RFC PATCH 4/8] preempt: Introduce CONFIG_PREEMPT_DYNAMIC Frederic Weisbecker
2021-01-22 16:53 ` Peter Zijlstra
2021-01-28 12:17 ` Frederic Weisbecker
2021-02-08 12:00 ` [tip: sched/core] " tip-bot2 for Michal Hocko
2021-02-17 13:17 ` tip-bot2 for Michal Hocko
2021-01-18 14:12 ` [RFC PATCH 5/8] preempt/dynamic: Provide cond_resched() and might_resched() static calls Frederic Weisbecker
2021-02-08 12:00 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra (Intel)
2021-02-17 13:17 ` tip-bot2 for Peter Zijlstra (Intel)
2021-01-18 14:12 ` [RFC PATCH 6/8] preempt/dynamic: Provide preempt_schedule[_notrace]() " Frederic Weisbecker
2021-01-21 21:58 ` Peter Zijlstra
2021-01-21 22:25 ` Peter Zijlstra
2021-01-22 16:52 ` Peter Zijlstra
2021-01-22 16:57 ` Ard Biesheuvel
2021-01-22 17:08 ` Peter Zijlstra
2021-02-08 12:00 ` [tip: sched/core] sched: Add /debug/sched_preempt tip-bot2 for Peter Zijlstra
2021-02-09 15:45 ` tip-bot2 for Peter Zijlstra
2021-02-17 13:17 ` tip-bot2 for Peter Zijlstra
2021-01-25 23:40 ` Josh Poimboeuf [this message]
2021-01-26 9:24 ` [RFC PATCH 6/8] preempt/dynamic: Provide preempt_schedule[_notrace]() static calls Peter Zijlstra
2021-01-26 23:57 ` Josh Poimboeuf
2021-01-27 9:13 ` Peter Zijlstra
2021-01-27 11:27 ` Peter Zijlstra
2021-01-27 15:59 ` Josh Poimboeuf
2021-01-27 16:19 ` Peter Zijlstra
2021-01-27 16:33 ` Josh Poimboeuf
2021-01-27 18:44 ` Peter Zijlstra
2021-01-27 19:00 ` Josh Poimboeuf
2021-01-27 19:02 ` Josh Poimboeuf
2021-01-27 23:18 ` Josh Poimboeuf
2021-02-03 14:04 ` Peter Zijlstra
2021-02-05 15:30 ` Peter Zijlstra
2021-02-06 2:31 ` Josh Poimboeuf
2021-02-06 9:03 ` Peter Zijlstra
2021-02-05 15:22 ` Peter Zijlstra
2021-02-08 12:00 ` [tip: sched/core] static_call: Allow module use without exposing static_call_key tip-bot2 for Josh Poimboeuf
2021-02-09 15:45 ` tip-bot2 for Josh Poimboeuf
2021-02-17 13:17 ` tip-bot2 for Josh Poimboeuf
2021-02-08 12:00 ` [tip: sched/core] preempt/dynamic: Provide preempt_schedule[_notrace]() static calls tip-bot2 for Peter Zijlstra (Intel)
2021-02-17 13:17 ` tip-bot2 for Peter Zijlstra (Intel)
2021-01-18 14:12 ` [RFC PATCH 7/8] preempt/dynamic: Provide irqentry_exit_cond_resched() static call Frederic Weisbecker
2021-02-08 12:00 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra (Intel)
2021-02-17 13:17 ` tip-bot2 for Peter Zijlstra (Intel)
2021-01-18 14:12 ` [RFC PATCH 8/8] preempt/dynamic: Support dynamic preempt with preempt= boot option Frederic Weisbecker
2021-02-08 12:00 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra (Intel)
2021-02-09 15:45 ` tip-bot2 for Peter Zijlstra (Intel)
2021-02-17 13:17 ` tip-bot2 for Peter Zijlstra (Intel)
2021-01-21 21:22 ` [RFC PATCH 0/7] preempt: Tune preemption flavour on boot v4 Peter Zijlstra
2021-01-22 15:02 ` Paul E. McKenney
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