Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934512AbbBCXvw (ORCPT ); Tue, 3 Feb 2015 18:51:52 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:56001 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756684AbbBCXvr (ORCPT ); Tue, 3 Feb 2015 18:51:47 -0500 Date: Tue, 3 Feb 2015 15:51:45 -0800 From: Andrew Morton To: Andrey Ryabinin Cc: linux-kernel@vger.kernel.org, Dmitry Vyukov , Konstantin Serebryany , Dmitry Chernenkov , Andrey Konovalov , Yuri Gribov , Konstantin Khlebnikov , Sasha Levin , Christoph Lameter , Joonsoo Kim , Dave Hansen , Andi Kleen , x86@kernel.org, linux-mm@kvack.org, Rusty Russell , James Bottomley Subject: Re: [PATCH v11 18/19] module: fix types of device tables aliases Message-Id: <20150203155145.632f352695fc558083d8c054@linux-foundation.org> In-Reply-To: <1422985392-28652-19-git-send-email-a.ryabinin@samsung.com> References: <1404905415-9046-1-git-send-email-a.ryabinin@samsung.com> <1422985392-28652-1-git-send-email-a.ryabinin@samsung.com> <1422985392-28652-19-git-send-email-a.ryabinin@samsung.com> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3751 Lines: 96 On Tue, 03 Feb 2015 20:43:11 +0300 Andrey Ryabinin wrote: > MODULE_DEVICE_TABLE() macro used to create aliases to device tables. > Normally alias should have the same type as aliased symbol. > > Device tables are arrays, so they have 'struct type##_device_id[x]' > types. Alias created by MODULE_DEVICE_TABLE() will have non-array type - > 'struct type##_device_id'. > > This inconsistency confuses compiler, it could make a wrong > assumption about variable's size which leads KASan to > produce a false positive report about out of bounds access. > > For every global variable compiler calls __asan_register_globals() > passing information about global variable (address, size, size with > redzone, name ...) __asan_register_globals() poison symbols > redzone to detect possible out of bounds accesses. > > When symbol has an alias __asan_register_globals() will be called > as for symbol so for alias. Compiler determines size of variable by > size of variable's type. Alias and symbol have the same address, > so if alias have the wrong size part of memory that actually belongs > to the symbol could be poisoned as redzone of alias symbol. > > By fixing type of alias symbol we will fix size of it, so > __asan_register_globals() will not poison valid memory. > > ... > > --- a/include/linux/module.h > +++ b/include/linux/module.h > @@ -135,7 +135,7 @@ void trim_init_extable(struct module *m); > #ifdef MODULE > /* Creates an alias so file2alias.c can find device table. */ > #define MODULE_DEVICE_TABLE(type, name) \ > - extern const struct type##_device_id __mod_##type##__##name##_device_table \ > +extern const typeof(name) __mod_##type##__##name##_device_table \ > __attribute__ ((unused, alias(__stringify(name)))) > #else /* !MODULE */ > #define MODULE_DEVICE_TABLE(type, name) This newly requires that `name' has been defined at the MODULE_DEVICE_TABLE expansion site. So drivers/scsi/be2iscsi/be_main.c explodes because we converted extern const struct pci_device_id __mod_pci__beiscsi_pci_id_table_device_table __attribute__ ((unused, alias("beiscsi_pci_id_table"))); into extern const typeof(beiscsi_pci_id_table) __mod_pci__beiscsi_pci_id_table_device_table __attribute__ ((unused, alias("beiscsi_pci_id_table"))); before beiscsi_pci_id_table was defined. There are probably others, so I'll start accumulating the fixes. From: Andrew Morton Subject: MODULE_DEVICE_TABLE: fix some callsites The patch "module: fix types of device tables aliases" newly requires that invokations of MODULE_DEVICE_TABLE(type, name); come *after* the definition of `name'. That is reasonable, but some drivers weren't doing this. Fix them. Cc: James Bottomley Cc: Andrey Ryabinin Signed-off-by: Andrew Morton --- drivers/scsi/be2iscsi/be_main.c | 1 - 1 file changed, 1 deletion(-) diff -puN drivers/scsi/be2iscsi/be_main.c~module_device_table-fix-some-callsites drivers/scsi/be2iscsi/be_main.c --- a/drivers/scsi/be2iscsi/be_main.c~module_device_table-fix-some-callsites +++ a/drivers/scsi/be2iscsi/be_main.c @@ -48,7 +48,6 @@ static unsigned int be_iopoll_budget = 1 static unsigned int be_max_phys_size = 64; static unsigned int enable_msix = 1; -MODULE_DEVICE_TABLE(pci, beiscsi_pci_id_table); MODULE_DESCRIPTION(DRV_DESC " " BUILD_STR); MODULE_VERSION(BUILD_STR); MODULE_AUTHOR("Emulex Corporation"); _ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/