Revision 1a512c0882bd311c5b5561840fcfbe4c25b8f319 authored by Arnd Bergmann on 24 April 2018, 21:19:51 UTC, committed by Thomas Gleixner on 27 April 2018, 15:06:29 UTC
A bugfix broke the x32 shmid64_ds and msqid64_ds data structure layout
(as seen from user space)  a few years ago: Originally, __BITS_PER_LONG
was defined as 64 on x32, so we did not have padding after the 64-bit
__kernel_time_t fields, After __BITS_PER_LONG got changed to 32,
applications would observe extra padding.

In other parts of the uapi headers we seem to have a mix of those
expecting either 32 or 64 on x32 applications, so we can't easily revert
the path that broke these two structures.

Instead, this patch decouples x32 from the other architectures and moves
it back into arch specific headers, partially reverting the even older
commit 73a2d096fdf2 ("x86: remove all now-duplicate header files").

It's not clear whether this ever made any difference, since at least
glibc carries its own (correct) copy of both of these header files,
so possibly no application has ever observed the definitions here.

Based on a suggestion from H.J. Lu, I tried out the tool from
https://github.com/hjl-tools/linux-header to find other such
bugs, which pointed out the same bug in statfs(), which also has
a separate (correct) copy in glibc.

Fixes: f4b4aae18288 ("x86/headers/uapi: Fix __BITS_PER_LONG value for x32 builds")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H . J . Lu" <hjl.tools@gmail.com>
Cc: Jeffrey Walton <noloader@gmail.com>
Cc: stable@vger.kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lkml.kernel.org/r/20180424212013.3967461-1-arnd@arndb.de

1 parent 3db3eb2
Raw File
kmemleak-test.c
/*
 * mm/kmemleak-test.c
 *
 * Copyright (C) 2008 ARM Limited
 * Written by Catalin Marinas <catalin.marinas@arm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#define pr_fmt(fmt) "kmemleak: " fmt

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/list.h>
#include <linux/percpu.h>
#include <linux/fdtable.h>

#include <linux/kmemleak.h>

struct test_node {
	long header[25];
	struct list_head list;
	long footer[25];
};

static LIST_HEAD(test_list);
static DEFINE_PER_CPU(void *, kmemleak_test_pointer);

/*
 * Some very simple testing. This function needs to be extended for
 * proper testing.
 */
static int __init kmemleak_test_init(void)
{
	struct test_node *elem;
	int i;

	pr_info("Kmemleak testing\n");

	/* make some orphan objects */
	pr_info("kmalloc(32) = %p\n", kmalloc(32, GFP_KERNEL));
	pr_info("kmalloc(32) = %p\n", kmalloc(32, GFP_KERNEL));
	pr_info("kmalloc(1024) = %p\n", kmalloc(1024, GFP_KERNEL));
	pr_info("kmalloc(1024) = %p\n", kmalloc(1024, GFP_KERNEL));
	pr_info("kmalloc(2048) = %p\n", kmalloc(2048, GFP_KERNEL));
	pr_info("kmalloc(2048) = %p\n", kmalloc(2048, GFP_KERNEL));
	pr_info("kmalloc(4096) = %p\n", kmalloc(4096, GFP_KERNEL));
	pr_info("kmalloc(4096) = %p\n", kmalloc(4096, GFP_KERNEL));
#ifndef CONFIG_MODULES
	pr_info("kmem_cache_alloc(files_cachep) = %p\n",
		kmem_cache_alloc(files_cachep, GFP_KERNEL));
	pr_info("kmem_cache_alloc(files_cachep) = %p\n",
		kmem_cache_alloc(files_cachep, GFP_KERNEL));
#endif
	pr_info("vmalloc(64) = %p\n", vmalloc(64));
	pr_info("vmalloc(64) = %p\n", vmalloc(64));
	pr_info("vmalloc(64) = %p\n", vmalloc(64));
	pr_info("vmalloc(64) = %p\n", vmalloc(64));
	pr_info("vmalloc(64) = %p\n", vmalloc(64));

	/*
	 * Add elements to a list. They should only appear as orphan
	 * after the module is removed.
	 */
	for (i = 0; i < 10; i++) {
		elem = kzalloc(sizeof(*elem), GFP_KERNEL);
		pr_info("kzalloc(sizeof(*elem)) = %p\n", elem);
		if (!elem)
			return -ENOMEM;
		INIT_LIST_HEAD(&elem->list);
		list_add_tail(&elem->list, &test_list);
	}

	for_each_possible_cpu(i) {
		per_cpu(kmemleak_test_pointer, i) = kmalloc(129, GFP_KERNEL);
		pr_info("kmalloc(129) = %p\n",
			per_cpu(kmemleak_test_pointer, i));
	}

	return 0;
}
module_init(kmemleak_test_init);

static void __exit kmemleak_test_exit(void)
{
	struct test_node *elem, *tmp;

	/*
	 * Remove the list elements without actually freeing the
	 * memory.
	 */
	list_for_each_entry_safe(elem, tmp, &test_list, list)
		list_del(&elem->list);
}
module_exit(kmemleak_test_exit);

MODULE_LICENSE("GPL");
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