From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f48.google.com (mail-pa0-f48.google.com [209.85.220.48]) by kanga.kvack.org (Postfix) with ESMTP id 7E9AE6B0075 for ; Wed, 21 Jan 2015 11:52:35 -0500 (EST) Received: by mail-pa0-f48.google.com with SMTP id ey11so2191438pad.7 for ; Wed, 21 Jan 2015 08:52:35 -0800 (PST) Received: from mailout3.w1.samsung.com (mailout3.w1.samsung.com. [210.118.77.13]) by mx.google.com with ESMTPS id ni2si1367385pdb.127.2015.01.21.08.52.22 for (version=TLSv1 cipher=RC4-MD5 bits=128/128); Wed, 21 Jan 2015 08:52:23 -0800 (PST) Received: from eucpsbgm2.samsung.com (unknown [203.254.199.245]) by mailout3.w1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0NIJ00IN1DPXSMA0@mailout3.w1.samsung.com> for linux-mm@kvack.org; Wed, 21 Jan 2015 16:56:22 +0000 (GMT) From: Andrey Ryabinin Subject: [PATCH v9 08/17] fs: dcache: manually unpoison dname after allocation to shut up kasan's reports Date: Wed, 21 Jan 2015 19:51:36 +0300 Message-id: <1421859105-25253-9-git-send-email-a.ryabinin@samsung.com> In-reply-to: <1421859105-25253-1-git-send-email-a.ryabinin@samsung.com> References: <1404905415-9046-1-git-send-email-a.ryabinin@samsung.com> <1421859105-25253-1-git-send-email-a.ryabinin@samsung.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: Andrey Ryabinin , Dmitry Vyukov , Konstantin Serebryany , Dmitry Chernenkov , Andrey Konovalov , Yuri Gribov , Konstantin Khlebnikov , Sasha Levin , Christoph Lameter , Joonsoo Kim , Andrew Morton , Dave Hansen , Andi Kleen , x86@kernel.org, linux-mm@kvack.org, Alexander Viro , "open list:FILESYSTEMS VFS..." We need to manually unpoison rounded up allocation size for dname to avoid kasan's reports in dentry_string_cmp(). When CONFIG_DCACHE_WORD_ACCESS=y dentry_string_cmp may access few bytes beyound requested in kmalloc() size. dentry_string_cmp() relates on that fact that dentry allocated using kmalloc and kmalloc internally round up allocation size. So this is not a bug, but this makes kasan to complain about such accesses. To avoid such reports we mark rounded up allocation size in shadow as accessible. Reported-by: Dmitry Vyukov Signed-off-by: Andrey Ryabinin --- fs/dcache.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/dcache.c b/fs/dcache.c index e368d4f..3c097f9 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -38,6 +38,8 @@ #include #include #include +#include + #include "internal.h" #include "mount.h" @@ -1430,6 +1432,9 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) } atomic_set(&p->u.count, 1); dname = p->name; + if (IS_ENABLED(CONFIG_DCACHE_WORD_ACCESS)) + kasan_unpoison_shadow(dname, + round_up(name->len + 1, sizeof(unsigned long))); } else { dname = dentry->d_iname; } -- 2.2.1 -- 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