Messages in this thread Patch in this message | | | Subject | [PATCH] cgroup/kmemcheck: No need to annotate base anymore | From | Steven Rostedt <> | Date | Tue, 26 Jul 2011 13:05:11 -0400 |
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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: [<c17e34e6>] ? printk+0x1d/0x1f^M [<c10e2941>] paint_ptr+0x4f/0x78 [<c178ab57>] kmemleak_not_leak+0x58/0x7d [<c108ae9f>] ? __rcu_read_unlock+0x9/0x7d [<c1cdb462>] kmemleak_init+0x19d/0x1e9 [<c1cbf771>] start_kernel+0x346/0x3ec [<c1cbf1b4>] ? loglevel+0x18/0x18 [<c1cbf0aa>] 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 <rostedt@goodmis.org>
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 <linux/vmalloc.h> #include <linux/cgroup.h> #include <linux/swapops.h> -#include <linux/kmemleak.h> 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;
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