From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga11.intel.com ([192.55.52.93]:13768 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390861AbeIUU7r (ORCPT ); Fri, 21 Sep 2018 16:59:47 -0400 From: Yu-cheng Yu Subject: [RFC PATCH v4 4/9] mm/mmap: Add IBT bitmap size to address space limit check Date: Fri, 21 Sep 2018 08:05:48 -0700 Message-ID: <20180921150553.21016-5-yu-cheng.yu@intel.com> In-Reply-To: <20180921150553.21016-1-yu-cheng.yu@intel.com> References: <20180921150553.21016-1-yu-cheng.yu@intel.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , 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 , Andy Lutomirski , Balbir Singh , Cyrill Gorcunov , Dave Hansen , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue Cc: Yu-cheng Yu Message-ID: <20180921150548.PgbWMZNN3GnUN4qdwTEfaS_y3Yt_nQThx9zFUiVIqMk@z> 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 --- 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 + #include 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 #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) return false; if (is_data_mapping(flags) && -- 2.17.1