From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f169.google.com (mail-pd0-f169.google.com [209.85.192.169]) by kanga.kvack.org (Postfix) with ESMTP id 20C1D6B00C5 for ; Wed, 5 Nov 2014 09:54:38 -0500 (EST) Received: by mail-pd0-f169.google.com with SMTP id y10so905453pdj.0 for ; Wed, 05 Nov 2014 06:54:37 -0800 (PST) Received: from mailout2.w1.samsung.com (mailout2.w1.samsung.com. [210.118.77.12]) by mx.google.com with ESMTPS id wu4si3318726pbc.19.2014.11.05.06.54.35 for (version=TLSv1 cipher=RC4-MD5 bits=128/128); Wed, 05 Nov 2014 06:54:36 -0800 (PST) Received: from eucpsbgm1.samsung.com (unknown [203.254.199.244]) by mailout2.w1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0NEK00CYLMVLX9B0@mailout2.w1.samsung.com> for linux-mm@kvack.org; Wed, 05 Nov 2014 14:57:22 +0000 (GMT) From: Andrey Ryabinin Subject: [PATCH v6 09/11] fs: dcache: manually unpoison dname after allocation to shut up kasan's reports Date: Wed, 05 Nov 2014 17:53:59 +0300 Message-id: <1415199241-5121-10-git-send-email-a.ryabinin@samsung.com> In-reply-to: <1415199241-5121-1-git-send-email-a.ryabinin@samsung.com> References: <1404905415-9046-1-git-send-email-a.ryabinin@samsung.com> <1415199241-5121-1-git-send-email-a.ryabinin@samsung.com> Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org Cc: Andrey Ryabinin , Dmitry Vyukov , Konstantin Serebryany , Dmitry Chernenkov , Andrey Konovalov , Yuri Gribov , Konstantin Khlebnikov , Sasha Levin , Christoph Lameter , Joonsoo Kim , Dave Hansen , Andi Kleen , Vegard Nossum , "H. Peter Anvin" , Dave Jones , x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Alexander Viro 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 | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/dcache.c b/fs/dcache.c index d5a23fd..d58ffcc6 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -38,6 +38,8 @@ #include #include #include +#include + #include "internal.h" #include "mount.h" @@ -1429,6 +1431,10 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) } atomic_set(&p->u.count, 1); dname = p->name; +#ifdef CONFIG_DCACHE_WORD_ACCESS + kasan_unpoison_shadow(dname, + round_up(name->len + 1, sizeof(unsigned long))); +#endif } else { dname = dentry->d_iname; } -- 2.1.3 -- 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