From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx145.postini.com [74.125.245.145]) by kanga.kvack.org (Postfix) with SMTP id 647166B0002 for ; Tue, 2 Apr 2013 16:29:29 -0400 (EDT) Message-ID: <515B3F98.5020101@zytor.com> Date: Tue, 02 Apr 2013 13:29:12 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 Subject: Re: [PATCH] x86: add phys addr validity check for /dev/mem mmap References: <1364905733-23937-1-git-send-email-fhrbata@redhat.com> <515B2802.1050405@zytor.com> <20130402191012.GC3314@dhcp-26-164.brq.redhat.com> In-Reply-To: <20130402191012.GC3314@dhcp-26-164.brq.redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Frantisek Hrbata Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, tglx@linutronix.de, mingo@redhat.com, x86@kernel.org, oleg@redhat.com, kamaleshb@in.ibm.com, hechjie@cn.ibm.com On 04/02/2013 12:10 PM, Frantisek Hrbata wrote: > > Hi, this is exactly what the patch is doing imho. Note that the > valid_phys_addr_range(), which is using the high_memory, is the same as the > default one in drivers/char/mem.c(#ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE). I > just added x86 specific check for valid_mmap_phys_addr_range and moved both > functions to arch/x86/mm/mmap.c, rather then modifying the default generic ones. > This is how other archs(arm) are doing it. > > Also valid_phys_addr_range is used just in read|write_mem and > valid_mmap_phys_addr_range is checked in mmap_mem and it calls phys_addr_valid > > static inline int phys_addr_valid(resource_size_t addr) > { > #ifdef CONFIG_PHYS_ADDR_T_64BIT > return !(addr >> boot_cpu_data.x86_phys_bits); > #else > return 1; > #endif > } > > I for sure could overlooked something, but this seems right to me. > OK, this is really confusing ... which isn't a *huge* surprise (the entire /dev/mem code has some gigantic bugs in it.) I think I need to do more of an in-depth review. The other question is why we don't call phys_addr_valid() everywhere. -hpa -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org