From: Marco Elver <elver@google.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
"the arch/x86 maintainers" <x86@kernel.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
kasan-dev <kasan-dev@googlegroups.com>,
LKML <linux-kernel@vger.kernel.org>,
Will Deacon <will@kernel.org>, Dmitry Vyukov <dvyukov@google.com>,
Alexander Potapenko <glider@google.com>,
Andrey Konovalov <andreyknvl@google.com>
Subject: Re: [PATCH 0/9] x86/entry fixes
Date: Thu, 4 Jun 2020 11:52:18 +0200 [thread overview]
Message-ID: <CANpmjNM48j4D7F+cgUrrof38d3nLuQjbW6pz3nTwxcZ5Q+GJqQ@mail.gmail.com> (raw)
In-Reply-To: <CANpmjNMyC+KHTbLFSxojV_CTK60t3ayJHxtyH4AckeMD2hGCtg@mail.gmail.com>
On Thu, 4 Jun 2020 at 08:00, Marco Elver <elver@google.com> wrote:
>
> On Wed, 3 Jun 2020 at 21:10, Marco Elver <elver@google.com> wrote:
> >
> > On Wed, 3 Jun 2020 at 20:16, Peter Zijlstra <peterz@infradead.org> wrote:
> > >
> > > On Wed, Jun 03, 2020 at 06:07:22PM +0200, Peter Zijlstra wrote:
> > > > On Wed, Jun 03, 2020 at 04:47:54PM +0200, Marco Elver wrote:
> > >
> > > > > With that in mind, you could whitelist "__ubsan_handle"-prefixed
> > > > > functions in objtool. Given the __always_inline+noinstr+__ubsan_handle
> > > > > case is quite rare, it might be reasonable.
> > > >
> > > > Yes, I think so. Let me go have dinner and then I'll try and do a patch
> > > > to that effect.
> > >
> > > Here's a slightly more radical patch, it unconditionally allows UBSAN.
> > >
> > > I've not actually boot tested this.. yet.
> > >
> > > ---
> > > Subject: x86/entry, ubsan, objtool: Whitelist __ubsan_handle_*()
> > > From: Peter Zijlstra <peterz@infradead.org>
> > > Date: Wed Jun 3 20:09:06 CEST 2020
> > >
> > > The UBSAN instrumentation only inserts external CALLs when things go
> > > 'BAD', much like WARN(). So treat them similar to WARN()s for noinstr,
> > > that is: allow them, at the risk of taking the machine down, to get
> > > their message out.
> > >
> > > Suggested-by: Marco Elver <elver@google.com>
> > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> >
> > This is much cleaner, as it gets us UBSAN coverage back. Seems to work
> > fine for me (only lightly tested), so
> >
> > Acked-by: Marco Elver <elver@google.com>
> >
> > Thanks!
>
> I was thinking that if we remove __no_sanitize_undefined from noinstr,
> we can lift the hard compiler restriction for UBSAN because
> __no_sanitize_undefined isn't used anywhere. Turns out, that attribute
> isn't broken on GCC <= 7, so I've sent v2 of my series:
> https://lkml.kernel.org/r/20200604055811.247298-1-elver@google.com
Now that hopefully KASAN/KCSAN/UBSAN are fine, I'm looking at adding a
patch for KCOV:
https://lkml.kernel.org/r/20200604095057.259452-1-elver@google.com
Will that work?
Thanks,
-- Marco
prev parent reply other threads:[~2020-06-04 9:52 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-03 11:40 [PATCH 0/9] x86/entry fixes Peter Zijlstra
2020-06-03 11:40 ` [PATCH 1/9] x86/entry: Fix irq_exit() Peter Zijlstra
2020-06-03 11:40 ` [PATCH 2/9] rcu: Fixup noinstr warnings Peter Zijlstra
2020-06-03 16:46 ` Paul E. McKenney
2020-06-03 17:13 ` Peter Zijlstra
2020-06-04 3:34 ` Paul E. McKenney
2020-06-04 6:02 ` Marco Elver
2020-06-04 14:14 ` Paul E. McKenney
2020-06-04 8:05 ` Peter Zijlstra
2020-06-04 14:17 ` Paul E. McKenney
2020-06-15 15:30 ` Peter Zijlstra
2020-06-15 15:52 ` Paul E. McKenney
2020-06-15 16:06 ` Peter Zijlstra
2020-06-15 15:49 ` Peter Zijlstra
2020-06-15 15:55 ` Peter Zijlstra
2020-06-15 16:24 ` Peter Zijlstra
2020-06-15 17:14 ` Paul E. McKenney
2020-06-15 18:33 ` Peter Zijlstra
2020-06-15 18:59 ` Paul E. McKenney
2020-06-15 20:00 ` Paul E. McKenney
2020-06-19 22:15 ` Paul E. McKenney
2020-06-23 20:46 ` Peter Zijlstra
2020-06-23 21:44 ` Paul E. McKenney
2020-06-24 7:52 ` Peter Zijlstra
2020-06-24 13:03 ` Paul E. McKenney
2020-06-03 11:40 ` [PATCH 3/9] x86/entry: __always_inline debugreg for noinstr Peter Zijlstra
2020-06-03 17:50 ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-06-03 11:40 ` [PATCH 4/9] x86/entry: __always_inline irqflags " Peter Zijlstra
2020-06-03 17:50 ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-06-03 11:40 ` [PATCH 5/9] x86/entry: __always_inline arch_atomic_* " Peter Zijlstra
2020-06-03 17:50 ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-06-03 11:40 ` [PATCH 6/9] x86/entry: Re-order #DB handler to avoid *SAN instrumentation Peter Zijlstra
2020-06-03 17:50 ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-06-03 11:40 ` [PATCH 7/9] lockdep: __always_inline more for noinstr Peter Zijlstra
2020-06-03 17:50 ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-06-03 11:40 ` [PATCH 8/9] x86/entry: __always_inline CR2 " Peter Zijlstra
2020-06-03 17:50 ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-06-03 11:40 ` [PATCH 9/9] x86/entry, cpumask: Provide non-instrumented variant of cpu_is_offline() Peter Zijlstra
2020-06-03 17:50 ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-06-03 12:00 ` [PATCH 0/9] x86/entry fixes Peter Zijlstra
2020-06-03 12:08 ` Peter Zijlstra
2020-06-03 12:08 ` Marco Elver
2020-06-03 12:18 ` Peter Zijlstra
2020-06-03 13:32 ` Marco Elver
2020-06-03 14:47 ` Marco Elver
2020-06-03 16:07 ` Peter Zijlstra
2020-06-03 17:26 ` Marco Elver
2020-06-03 18:16 ` Peter Zijlstra
2020-06-03 19:10 ` Marco Elver
2020-06-04 6:00 ` Marco Elver
2020-06-04 9:52 ` Marco Elver [this message]
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