From: Eugene Syromiatnikov <esyr@redhat.com>
To: Yu-cheng Yu <yu-cheng.yu@intel.com>
Cc: x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
linux-api@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Andy Lutomirski <luto@amacapital.net>,
Balbir Singh <bsingharora@gmail.com>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Florian Weimer <fweimer@redhat.com>,
"H.J. Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
Jonathan Corbet <corbet@lwn.net>,
Kees Cook <keescook@chromium.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
Nadav Amit <nadav.amit@gmail.com>,
Oleg Nesterov <oleg@redhat.com>, Pavel Machek <pavel@ucw.cz>,
Peter Zijlstra <peterz@infradead.org>,
Randy Dunlap <rdunlap@infradead.org>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>
Subject: Re: [RFC PATCH v4 4/9] mm/mmap: Add IBT bitmap size to address space limit check
Date: Wed, 3 Oct 2018 22:21:46 +0200 [thread overview]
Message-ID: <20181003202146.GG32759@asgard.redhat.com> (raw)
Message-ID: <20181003202146.rbeNDic9MDx52QE8ZYCs_m3ux2De66Djf6oZeo-K6pk@z> (raw)
In-Reply-To: <20180921150553.21016-5-yu-cheng.yu@intel.com>
On Fri, Sep 21, 2018 at 08:05:48AM -0700, Yu-cheng Yu wrote:
> The indirect branch tracking legacy bitmap takes a large address
> space. This causes may_expand_vm() failure on the address limit
> check. For a IBT-enabled task, add the bitmap size to the
> address limit.
>
> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
> ---
> arch/x86/include/uapi/asm/resource.h | 5 +++++
> include/uapi/asm-generic/resource.h | 3 +++
> mm/mmap.c | 12 +++++++++++-
> 3 files changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/uapi/asm/resource.h b/arch/x86/include/uapi/asm/resource.h
> index 04bc4db8921b..0741b2a6101a 100644
> --- a/arch/x86/include/uapi/asm/resource.h
> +++ b/arch/x86/include/uapi/asm/resource.h
> @@ -1 +1,6 @@
> +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
> +#ifdef CONFIG_X86_INTEL_CET
> +#define rlimit_as_extra() current->thread.cet.ibt_bitmap_size
> +#endif
Does this really belong to UAPI?
> +
> #include <asm-generic/resource.h>
> diff --git a/include/uapi/asm-generic/resource.h b/include/uapi/asm-generic/resource.h
> index f12db7a0da64..8a7608a09700 100644
> --- a/include/uapi/asm-generic/resource.h
> +++ b/include/uapi/asm-generic/resource.h
> @@ -58,5 +58,8 @@
> # define RLIM_INFINITY (~0UL)
> #endif
>
> +#ifndef rlimit_as_extra
> +#define rlimit_as_extra() 0
> +#endif
And this?
> #endif /* _UAPI_ASM_GENERIC_RESOURCE_H */
> diff --git a/mm/mmap.c b/mm/mmap.c
> index fa581ced3f56..397b8cb0b0af 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -3237,7 +3237,17 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
> */
> bool may_expand_vm(struct mm_struct *mm, vm_flags_t flags, unsigned long npages)
> {
> - if (mm->total_vm + npages > rlimit(RLIMIT_AS) >> PAGE_SHIFT)
> + unsigned long as_limit = rlimit(RLIMIT_AS);
> + unsigned long as_limit_plus = as_limit + rlimit_as_extra();
> +
> + /* as_limit_plus overflowed */
> + if (as_limit_plus < as_limit)
> + as_limit_plus = RLIM_INFINITY;
> +
> + if (as_limit_plus > as_limit)
> + as_limit = as_limit_plus;
> +
> + if (mm->total_vm + npages > as_limit >> PAGE_SHIFT)
I wonder, how realistic a scenario where a userspace application enables IBT,
configures a huge prefetchable IO memory region (that just ignores bits
of offset beyond 16, for example), and start repeatedly loading a legacy
library there at different linear addresses.
> return false;
>
> if (is_data_mapping(flags) &&
> --
> 2.17.1
>
next prev parent reply other threads:[~2018-10-04 3:11 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-21 15:05 [RFC PATCH v4 0/9] Control Flow Enforcement: Branch Tracking, PTRACE Yu-cheng Yu
2018-09-21 15:05 ` Yu-cheng Yu
2018-09-21 15:05 ` [RFC PATCH v4 1/9] x86/cet/ibt: Add Kconfig option for user-mode Indirect Branch Tracking Yu-cheng Yu
2018-09-21 15:05 ` Yu-cheng Yu
2018-09-21 15:05 ` [RFC PATCH v4 2/9] x86/cet/ibt: User-mode indirect branch tracking support Yu-cheng Yu
2018-09-21 15:05 ` Yu-cheng Yu
2018-10-03 18:58 ` Eugene Syromiatnikov
2018-10-03 18:58 ` Eugene Syromiatnikov
2018-09-21 15:05 ` [RFC PATCH v4 3/9] x86/cet/ibt: Add IBT legacy code bitmap allocation function Yu-cheng Yu
2018-09-21 15:05 ` Yu-cheng Yu
2018-10-03 19:57 ` Eugene Syromiatnikov
2018-10-03 19:57 ` Eugene Syromiatnikov
2018-10-05 16:13 ` Yu-cheng Yu
2018-10-05 16:13 ` Yu-cheng Yu
2018-10-05 16:28 ` Andy Lutomirski
2018-10-05 16:28 ` Andy Lutomirski
2018-10-05 16:58 ` Yu-cheng Yu
2018-10-05 16:58 ` Yu-cheng Yu
2018-10-05 17:07 ` Andy Lutomirski
2018-10-05 17:07 ` Andy Lutomirski
2018-10-05 17:26 ` Eugene Syromiatnikov
2018-10-05 17:26 ` Eugene Syromiatnikov
2018-10-10 15:56 ` Yu-cheng Yu
2018-10-10 15:56 ` Yu-cheng Yu
2018-10-04 16:11 ` Andy Lutomirski
2018-10-04 16:11 ` Andy Lutomirski
2018-09-21 15:05 ` [RFC PATCH v4 4/9] mm/mmap: Add IBT bitmap size to address space limit check Yu-cheng Yu
2018-09-21 15:05 ` Yu-cheng Yu
2018-10-03 20:21 ` Eugene Syromiatnikov [this message]
2018-10-03 20:21 ` Eugene Syromiatnikov
2018-09-21 15:05 ` [RFC PATCH v4 5/9] x86/cet/ibt: ELF header parsing for IBT Yu-cheng Yu
2018-09-21 15:05 ` Yu-cheng Yu
2018-09-21 15:05 ` [RFC PATCH v4 6/9] x86/cet/ibt: Add arch_prctl functions " Yu-cheng Yu
2018-09-21 15:05 ` Yu-cheng Yu
2018-10-04 13:28 ` Eugene Syromiatnikov
2018-10-04 13:28 ` Eugene Syromiatnikov
2018-10-04 15:37 ` Yu-cheng Yu
2018-10-04 15:37 ` Yu-cheng Yu
2018-10-04 16:07 ` Florian Weimer
2018-10-04 16:07 ` Florian Weimer
2018-10-04 16:12 ` Andy Lutomirski
2018-10-04 16:12 ` Andy Lutomirski
2018-10-04 16:25 ` Yu-cheng Yu
2018-10-04 16:25 ` Yu-cheng Yu
2018-10-04 16:08 ` Andy Lutomirski
2018-10-04 16:08 ` Andy Lutomirski
2018-09-21 15:05 ` [RFC PATCH v4 7/9] x86/cet/ibt: Add ENDBR to op-code-map Yu-cheng Yu
2018-09-21 15:05 ` Yu-cheng Yu
2018-09-21 15:05 ` [RFC PATCH v4 8/9] x86: Insert endbr32/endbr64 to vDSO Yu-cheng Yu
2018-09-21 15:05 ` Yu-cheng Yu
2018-09-21 15:05 ` [RFC PATCH v4 9/9] x86/cet: Add PTRACE interface for CET Yu-cheng Yu
2018-09-21 15:05 ` Yu-cheng Yu
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