From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1519679659; cv=none; d=google.com; s=arc-20160816; b=G3AZQh+vWfqRWU7U8RqupH8dr7Thc2yrv4doIAmN/l/cyir4m4b7eXygkurPWQUA5q MajgBfHh+QdXNJ3sno+qWV0HzdLdOSGpFugV7W9ABJimSycD0FOfuC2Sikd2uMSRuh5A 9lixFbFKCFoAcTXr7kSTYNfX6p8884Y6e/s2pwClDojaSv30xKJauHUOxVlxTWfCQSix aO2VVIj4RaK7aR6npwUmMe9k8qx4s/NYQDeFiG4Xk5Ue9iTi4Dt1FrRfKIUg/GEkYek4 zROP2WRikfHVaUp62QLzeM6e8ceZUCjDcrcgN9wiCZXWLes7hhGv8uX8PMx8qYI8qTCu y49w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:date:subject:cc:to:from:dkim-signature :arc-authentication-results; bh=i289Kps8/WCOZz8b3MsDosmihuLz7vh+cC/s4mwF54Q=; b=BOEXkGysut2ieyRp/q2XPT89BdBleEUm2p2ZKOCjb4ROKYtI+4QZPljwFCRvCYfXjl nmzZuWGF4hjiIPZwxI49MjQpuW8Nbsc5R4J2RjM0Q/n1p2fOJ+DBy59w7c/0V4GJbnvd vn9B/RQglvfeZTPIiD1cA8DBCvASozvfWyb5Ikasvz5k/wXaQMzmYJJzHjydlB6c+l+c BW8IlFOYOMAHg0FeNoploFojaqDhQeR0BdKyj87RZIhBsMmmVtpsmjL8xEqsdqJ21Oyp pnuoU+iyMJedJyyO00UdFAGRxVO7PkdRp+bD8BmLvd7PoT1c1DGSvMesd6/RiycFS/w7 oaqQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=eYxOgkXv; spf=pass (google.com: domain of blackzert@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=blackzert@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=eYxOgkXv; spf=pass (google.com: domain of blackzert@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=blackzert@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com X-Google-Smtp-Source: AG47ELtAGvo+0WJlDAbR8LYCOPjEL9nGvpT1/dz/MMQ2K2zElroLxwhXqzo7vppqwBsNmV9C8mq0kw== From: Ilya Smith To: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, kirill.shutemov@linux.intel.com, dsafonov@virtuozzo.com, mhocko@suse.com, hughd@google.com, gregkh@linuxfoundation.org, craigb@google.com, oleg@redhat.com, linux-kernel@vger.kernel.org Cc: Ilya Smith Subject: [RFC PATCH] Take mmap_min_addr into account while choosing unmapped address for x86-64. Date: Tue, 27 Feb 2018 00:12:57 +0300 Message-Id: <20180226211257.63067-1-blackzert@gmail.com> X-Mailer: git-send-email 2.14.1 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1593499619093217840?= X-GMAIL-MSGID: =?utf-8?q?1593499619093217840?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: It prevent situation when vm_unmapped_area chose address between PAGE_SIZE and mmap_min_addr range. In this case mmap will fail with EPERM without a good reason. As test-case of such situation we may hard-code address between PAGE_SIZE and 65536 inside unmapped_area_topdown function. Signed-off-by: Ilya Smith --- arch/x86/kernel/sys_x86_64.c | 5 +++-- arch/x86/mm/mmap.c | 4 ++++ 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c index 676774b9bb8d..1752fe5cb735 100644 --- a/arch/x86/kernel/sys_x86_64.c +++ b/arch/x86/kernel/sys_x86_64.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include @@ -185,7 +186,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, return addr; /* requested length too big for entire address space */ - if (len > TASK_SIZE) + if (len > TASK_SIZE - mmap_min_addr) return -ENOMEM; /* No address checking. See comment at mmap_address_hint_valid() */ @@ -210,7 +211,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, info.flags = VM_UNMAPPED_AREA_TOPDOWN; info.length = len; - info.low_limit = PAGE_SIZE; + info.low_limit = max(PAGE_SIZE, mmap_min_addr); info.high_limit = get_mmap_base(0); /* diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c index 155ecbac9e28..b6d0c317639e 100644 --- a/arch/x86/mm/mmap.c +++ b/arch/x86/mm/mmap.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include "physaddr.h" @@ -220,6 +221,9 @@ bool mmap_address_hint_valid(unsigned long addr, unsigned long len) if (TASK_SIZE - len < addr) return false; + if (addr < mmap_min_addr) + return false; + return (addr > DEFAULT_MAP_WINDOW) == (addr + len > DEFAULT_MAP_WINDOW); } -- 2.14.1