From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754631Ab1I3Bsh (ORCPT ); Thu, 29 Sep 2011 21:48:37 -0400 Received: from mail-yx0-f174.google.com ([209.85.213.174]:41049 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751494Ab1I3Bsf (ORCPT ); Thu, 29 Sep 2011 21:48:35 -0400 Date: Thu, 29 Sep 2011 20:48:24 -0500 From: Jonathan Nieder To: Linus Torvalds Cc: linux-kernel@vger.kernel.org, Andrew Morton , Nelson Elhage , Steven Rostedt , Catalin Marinas Subject: [PATCH 1/2] cgroup/kmemleak: Annotate alloc_page() for cgroup allocations Message-ID: <20110930014824.GA2455@elie.chipublib.org> References: <20110930014334.GA2368@elie.chipublib.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110930014334.GA2368@elie.chipublib.org> User-Agent: Mutt/1.5.21+46 (b01d63af6fea) (2011-07-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steven Rostedt Date: Tue, 26 Jul 2011 15:19:16 -0400 When the cgroup base was allocated with kmalloc, it was necessary to annotate the variable with kmemleak_not_leak(). But because it has recently been changed to be allocated with alloc_page() (which skips kmemleak checks) causes a warning on boot up. 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. If alloc_page() fails then it defaults back to vmalloc() which still uses the kmemleak_alloc() which makes us still need the kmemleak_not_leak() call. The solution is to call the kmemleak_alloc() directly if the alloc_page() succeeds. Reviewed-by: Michal Hocko Signed-off-by: Steven Rostedt Acked-by: Catalin Marinas Signed-off-by: Jonathan Nieder --- This patch is taken from [1]. The only change I made is to correct "kmemcheck" above to "kmemleak" as suggested by Catalin. Seems to work ok. :) [1] http://thread.gmane.org/gmane.linux.kernel/1171696/focus=1178619 mm/page_cgroup.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-) diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c index 39d216d535ea..95e564cfe788 100644 --- a/mm/page_cgroup.c +++ b/mm/page_cgroup.c @@ -133,10 +133,13 @@ struct page *lookup_cgroup_page(struct page_cgroup *pc) static void *__meminit alloc_page_cgroup(size_t size, int nid) { void *addr = NULL; + gfp_t flags = GFP_KERNEL | __GFP_NOWARN; - addr = alloc_pages_exact_nid(nid, size, GFP_KERNEL | __GFP_NOWARN); - if (addr) + addr = alloc_pages_exact_nid(nid, size, flags); + if (addr) { + kmemleak_alloc(addr, size, 1, flags); return addr; + } if (node_state(nid, N_HIGH_MEMORY)) addr = vmalloc_node(size, nid); -- 1.7.7.rc1