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From: Marco Elver <elver@google.com>
To: George Popescu <georgepope@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	kvmarm@lists.cs.columbia.edu, Fangrui Song <maskray@google.com>,
	maz@kernel.org, Masahiro Yamada <masahiroy@kernel.org>,
	clang-built-linux <clang-built-linux@googlegroups.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Kees Cook <keescook@chromium.org>, Arnd Bergmann <arnd@arndb.de>,
	Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
	broonie@kernel.org, Nathan Chancellor <natechancellor@gmail.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Michal Marek <michal.lkml@markovi.net>,
	Nick Desaulniers <ndesaulniers@google.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 06/14] Fix CFLAGS for UBSAN_BOUNDS on Clang
Date: Wed, 16 Sep 2020 10:32:40 +0200	[thread overview]
Message-ID: <CANpmjNMT9-a8qKZSvGWBPAb9x9y1DkrZMSvHGq++_TcEv=7AuA@mail.gmail.com> (raw)
In-Reply-To: <20200916074027.GA2946587@google.com>

On Wed, 16 Sep 2020 at 09:40, George Popescu <georgepope@google.com> wrote:
>
> On Tue, Sep 15, 2020 at 07:32:28PM +0200, Marco Elver wrote:
> > On Tue, 15 Sep 2020 at 14:01, George Popescu <georgepope@google.com> wrote:
> > >
> > > On Tue, Sep 15, 2020 at 01:18:11PM +0200, Marco Elver wrote:
> > > > On Tue, 15 Sep 2020 at 12:25, George Popescu <georgepope@google.com> wrote:
> > > > > On Mon, Sep 14, 2020 at 03:13:14PM -0700, Kees Cook wrote:
> > > > > > On Mon, Sep 14, 2020 at 05:27:42PM +0000, George-Aurelian Popescu wrote:
> > > > > > > From: George Popescu <georgepope@google.com>
> > > > > > >
> > > > > > > When the kernel is compiled with Clang, UBSAN_BOUNDS inserts a brk after
> > > > > > > the handler call, preventing it from printing any information processed
> > > > > > > inside the buffer.
> > > > > > > For Clang -fsanitize=bounds expands to -fsanitize=array-bounds and
> > > > > > > -fsanitize=local-bounds, and the latter adds a brk after the handler
> > > > > > > call
> > > > > >
> > > > > This would mean losing the local-bounds coverage. I tried to  test it without
> > > > > local-bounds and with a locally defined array on the stack and it works fine
> > > > > (the handler is called and the error reported). For me it feels like
> > > > > --array-bounds and --local-bounds are triggered for the same type of
> > > > > undefined_behaviours but they are handling them different.
> > > >
> > > > Does -fno-sanitize-trap=bounds help?>
> > >
> > > I tried replacing it with:
> > >       ifdef CONFIG_CC_IS_CLANG
> > >             CFLAGS_UBSAN += $(call cc-option, -fno-sanitize-trap=bounds)
> > >             CFLAGS_UBSAN += $(call cc-option, -fsanitize=bounds)
> > >       else
> > >             CFLAGS_UBSAN += $(call cc-option, -fsanitize=bounds)
> > >       endif
> > >
> > > The code traps.
> >
> > What's your config? Do you have CONFIG_UBSAN_TRAP=y? If so, you have 2
> > options: honor UBSAN_TRAP and crash the kernel, or have a
> > 'CFLAGS_REMOVE_... = -fsanitize-undefined-trap-on-error' for the files
> > where you can't deal with traps>
>
> I don't have CONFIG_UBSAN_TRAP=y. My .config is:
> CONFIG_ARCH_HAS_UBSAN_SANITIZE_ALL=y
> CONFIG_UBSAN=y
> # CONFIG_UBSAN_TRAP is not set
> CONFIG_UBSAN_KCOV_BROKEN=y
> CONFIG_UBSAN_MISC=y
> CONFIG_UBSAN_SANITIZE_ALL=y
> # CONFIG_UBSAN_ALIGNMENT is not set
> CONFIG_TEST_UBSAN=m

Your full config would be good, because it includes compiler version etc.
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  reply	other threads:[~2020-09-16  9:01 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-14 17:27 [PATCH 00/14] UBSan Enablement for hyp/nVHE code George-Aurelian Popescu
2020-09-14 17:27 ` [PATCH 01/14] KVM: arm64: Enable UBSan instrumentation in nVHE hyp code George-Aurelian Popescu
2020-09-14 17:27 ` [PATCH 02/14] KVM: arm64: Define a macro for storing a value inside a per_cpu variable George-Aurelian Popescu
2020-09-14 17:27 ` [PATCH 03/14] KVM: arm64: Add support for creating and checking a logging buffer inside hyp/nVHE George-Aurelian Popescu
2020-10-01 10:07   ` Andrew Scull
2020-09-14 17:27 ` [PATCH 04/14] KVM: arm64: Add support for buffer usage George-Aurelian Popescu
2020-09-14 17:27 ` [PATCH 05/14] KVM: arm64: Define a buffer that can pass UBSan data from hyp/nVHE to kernel George-Aurelian Popescu
2020-09-15 13:25   ` George Popescu
2020-10-01 10:51   ` Andrew Scull
2020-09-14 17:27 ` [PATCH 06/14] Fix CFLAGS for UBSAN_BOUNDS on Clang George-Aurelian Popescu
2020-09-14 21:17   ` Nick Desaulniers
2020-09-14 22:13   ` Kees Cook
2020-09-15 10:24     ` George Popescu
2020-09-15 11:18       ` Marco Elver
2020-09-15 12:01         ` George Popescu
2020-09-15 17:32           ` Marco Elver
2020-09-16  7:40             ` George Popescu
2020-09-16  8:32               ` Marco Elver [this message]
2020-09-16 12:14                 ` George Popescu
2020-09-16 13:40                   ` Marco Elver
2020-09-17  6:37                     ` Marco Elver
2020-09-17 11:35                       ` George Popescu
2020-09-17 22:21                         ` Kees Cook
2020-09-17 22:17       ` Kees Cook
2020-09-14 17:27 ` [PATCH 07/14] KVM: arm64: Enable UBSAN_BOUNDS for the both the kernel and hyp/nVHE George-Aurelian Popescu
2020-10-01 10:57   ` Andrew Scull
2020-09-14 17:27 ` [PATCH 08/14] KVM: arm64: Enable UBsan check for unreachable code inside hyp/nVHE code George-Aurelian Popescu
2020-09-14 17:27 ` [PATCH 09/14] KVM: arm64: Enable shift out of bounds undefined behaviour check for hyp/nVHE George-Aurelian Popescu
2020-09-14 17:27 ` [PATCH 10/14] KVM: arm64: __ubsan_handle_load_invalid_value hyp/nVHE implementation George-Aurelian Popescu
2020-09-14 17:27 ` [PATCH 11/14] KVM: arm64: Detect type mismatch undefined behaviour from hyp/nVHE code George-Aurelian Popescu
2020-09-14 17:27 ` [PATCH 12/14] KVM: arm64: Detect arithmetic overflow is inside hyp/nVHE George-Aurelian Popescu
2020-09-14 17:27 ` [PATCH 13/14] KVM: arm64: Enable the CONFIG_TEST UBSan for PKVM George-Aurelian Popescu
2020-09-14 17:27 ` [PATCH 14/14] DO NOT MERGE: Enable configs to test the patch series George-Aurelian Popescu

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