From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754005Ab1GZRFX (ORCPT ); Tue, 26 Jul 2011 13:05:23 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.124]:43254 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753975Ab1GZRFR (ORCPT ); Tue, 26 Jul 2011 13:05:17 -0400 X-Authority-Analysis: v=1.1 cv=s3eDhkhcaTLnj7IEXy8aaXUiY7FbET0mf+/2Xe0elbc= c=1 sm=0 a=BYjp-8hqa-kA:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=OPBmh+XkhLl+Enan7BmTLg==:17 a=meVymXHHAAAA:8 a=9ouZYpg21h5U8RkBtYwA:9 a=2Wn9l-nSmqVnJ2ieHB4A:7 a=PUjeQqilurYA:10 a=jeBq3FmKZ4MA:10 a=OPBmh+XkhLl+Enan7BmTLg==:117 X-Cloudmark-Score: 0 X-Originating-IP: 67.242.120.143 Subject: [PATCH] cgroup/kmemcheck: No need to annotate base anymore From: Steven Rostedt To: LKML Cc: Johannes Weiner , KAMEZAWA Hiroyuki , Daisuke Nishimura , Balbir Singh , Minchan Kim , Randy Dunlap , Andrew Morton , Michal Hocko , Dave Hansen Content-Type: text/plain; charset="ISO-8859-15" Date: Tue, 26 Jul 2011 13:05:11 -0400 Message-ID: <1311699911.3526.87.camel@gandalf.stny.rr.com> Mime-Version: 1.0 X-Mailer: Evolution 2.32.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When the cgroup base was allocated with kmalloc, it was necessary to annotate the variable with kmemcheck_not_leak(). But because it has recently been changed to be allocated with alloc_page(), the annotation is no longer needed. I was triggering this output: allocated 8388608 bytes of page_cgroup please try 'cgroup_disable=memory' option if you don't want memory cgroups kmemleak: Trying to color unknown object at 0xf5840000 as Grey Pid: 0, comm: swapper Not tainted 3.0.0-test #12 Call Trace: [] ? printk+0x1d/0x1f^M [] paint_ptr+0x4f/0x78 [] kmemleak_not_leak+0x58/0x7d [] ? __rcu_read_unlock+0x9/0x7d [] kmemleak_init+0x19d/0x1e9 [] start_kernel+0x346/0x3ec [] ? loglevel+0x18/0x18 [] i386_start_kernel+0xaa/0xb0 After a bit of debugging I tracked the object 0xf840000 (and others) down to the cgroup code. The change from allocating base with kmalloc to alloc_page() has the base not calling kmemleak_alloc() which adds the pointer to the object_tree_root, but kmemleak_not_leak() adds it to the crt_early_log[] table. On kmemleak_init(), the entry is found in the early_log[] but not the object_tree_root, and this error message is displayed. Signed-off-by: Steven Rostedt diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c index 53bffc6..955a49f 100644 --- a/mm/page_cgroup.c +++ b/mm/page_cgroup.c @@ -9,7 +9,6 @@ #include #include #include -#include static void __meminit init_page_cgroup(struct page_cgroup *pc, unsigned long id) { @@ -179,13 +178,6 @@ static int __meminit init_section_page_cgroup(unsigned long pfn, int nid) table_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION; base = alloc_page_cgroup(table_size, nid); - /* - * The value stored in section->page_cgroup is (base - pfn) - * and it does not point to the memory block allocated above, - * causing kmemleak false positives. - */ - kmemleak_not_leak(base); - if (!base) { printk(KERN_ERR "page cgroup allocation failure\n"); return -ENOMEM;