From: Mike Krinkin <krinkin.m.u@gmail.com>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: akpm@linux-foundation.org, ying.huang@linux.intel.com,
davej@codemonkey.org.uk, x86@kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH -mm] ubsan, x86: disable alignemnt checks for arch/x86/*
Date: Tue, 2 Feb 2016 00:09:00 +0300 [thread overview]
Message-ID: <20160201210900.GA3476@kmu-tp-x230> (raw)
In-Reply-To: <1454346499-31868-1-git-send-email-aryabinin@virtuozzo.com>
Works well for me, thank you.
Tested-by: Mike Krinkin <krinkin.m.u@gmail.com>
On Mon, Feb 01, 2016 at 08:08:19PM +0300, Andrey Ryabinin wrote:
> On 01/30/2016 03:36 AM, Mike Krinkin wrote:
> > option CONFIG_UBSAN_ALIGNMENT breaks x86-64 kernel with lockdep enabled,
> > i. e kernel with CONFIG_UBSAN_ALIGNMENT fails to load without even any
> > error message.
> >
> > The problem is that ubsan callbacks use spinlocks and might be called
> > before lockdep is initialized.
>
> There is also report from kernel test robot:
> [ 0.000000] WARNING: lockdep init error: lock 'report_lock' was acquired before lockdep_init().
> [ 0.000000] Call stack leading to lockdep invocation was:
> [ 0.000000] [<b9e30ec5>] save_stack_trace+0x26/0x16d
> [ 0.000000] [<b9f98054>] __lock_acquire+0x237/0x15a4
> [ 0.000000] [<b9f994db>] lock_acquire+0x11a/0x1a9
> [ 0.000000] [<bae228f9>] _raw_spin_lock_irqsave+0x39/0x49
> [ 0.000000] [<ba5df852>] ubsan_prologue+0x1e/0x51
> [ 0.000000] [<ba5dfb02>] __ubsan_handle_type_mismatch+0xbd/0x14a
> [ 0.000000] [<bbca63c3>] reserve_ebda_region+0x8b/0x1bb
> [ 0.000000] [<bbca632c>] i386_start_kernel+0xf6/0x102
> [ 0.000000] [<ffffffff>] 0xffffffff
>
> Let's disable aligment checks for x86-specific code since those are not
> useful.
> Changes around CFLAGS_UBSAN in this patch needed to be sure that cflags
> from 'subdir-ccflags-' appears only after CFLAGS_UBSAN.
>
> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
> Reported-by: kernel test robot <ying.huang@linux.intel.com>
> Reported-by: Mike Krinkin <krinkin.m.u@gmail.com>
> ---
> Makefile | 2 +-
> arch/x86/Kbuild | 2 ++
> scripts/Makefile.lib | 4 ++--
> scripts/Makefile.ubsan | 5 +++++
> 4 files changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index 6c1a3c2..1da29a0 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -411,7 +411,7 @@ export MAKE AWK GENKSYMS INSTALLKERNEL PERL PYTHON UTS_MACHINE
> export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
>
> export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS
> -export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE CFLAGS_GCOV CFLAGS_KASAN CFLAGS_UBSAN
> +export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE CFLAGS_GCOV CFLAGS_KASAN
> export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
> export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
> export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
> diff --git a/arch/x86/Kbuild b/arch/x86/Kbuild
> index 1538562..f1348ce 100644
> --- a/arch/x86/Kbuild
> +++ b/arch/x86/Kbuild
> @@ -21,3 +21,5 @@ obj-y += platform/
> obj-y += net/
>
> obj-$(CONFIG_KEXEC_FILE) += purgatory/
> +
> +subdir-ccflags-$(CONFIG_UBSAN_ALIGNMENT) := $(call cc-option, -fno-sanitize=alignment)
> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> index 2edbcad..d7342cf 100644
> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -132,8 +132,8 @@ endif
>
> ifeq ($(CONFIG_UBSAN),y)
> _c_flags += $(if $(patsubst n%,, \
> - $(UBSAN_SANITIZE_$(basetarget).o)$(UBSAN_SANITIZE)$(CONFIG_UBSAN_SANITIZE_ALL)), \
> - $(CFLAGS_UBSAN))
> + $(UBSAN_SANITIZE_$(basetarget).o)$(UBSAN_SANITIZE)$(CONFIG_UBSAN_SANITIZE_ALL)),, \
> + $(DISABLE_UBSAN))
> endif
>
> # If building the kernel in a separate objtree expand all occurrences
> diff --git a/scripts/Makefile.ubsan b/scripts/Makefile.ubsan
> index 77ce538..91c1dd3 100644
> --- a/scripts/Makefile.ubsan
> +++ b/scripts/Makefile.ubsan
> @@ -18,4 +18,9 @@ endif
> # -fsanitize=* options makes GCC less smart than usual and
> # increase number of 'maybe-uninitialized false-positives
> CFLAGS_UBSAN += $(call cc-option, -Wno-maybe-uninitialized)
> +
> + KBUILD_CFLAGS += $(CFLAGS_UBSAN)
> + export DISABLE_UBSAN
> + DISABLE_UBSAN := $(call cc-option, -fno-sanitize=undefined)
> + DISABLE_UBSAN += $(call cc-option, -Wmaybe-uninitialized)
> endif
> --
> 2.4.10
>
prev parent reply other threads:[~2016-02-01 21:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-01 17:08 [PATCH -mm] ubsan, x86: disable alignemnt checks for arch/x86/* Andrey Ryabinin
2016-02-01 18:24 ` kbuild test robot
2016-02-01 19:09 ` kbuild test robot
2016-02-01 20:16 ` kbuild test robot
2016-02-01 21:09 ` Mike Krinkin [this message]
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