linux/samples/kmemleak/kmemleak-test.c
Jim Cromie dcb8cbb58a kmemleak-test: drop __init to get better backtrace
Drop the __init on kmemleak_test_init().  With it, the storage is
reclaimed, but then the symbol isn't available for "%pS" rendering,
and the backtrace gets a bare pointer where the actual leak happened.

unreferenced object 0xffff88800a2b0800 (size 1024):
  comm "modprobe", pid 413, jiffies 4294953430
  hex dump (first 32 bytes):
    73 02 00 00 75 01 00 68 02 00 00 01 00 00 00 04  s...u..h........
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000fabad728>] kmalloc_trace+0x26/0x90
    [<00000000ef738764>] 0xffffffffc02350a2
    [<00000000004e5795>] do_one_initcall+0x43/0x210
    [<00000000d768905e>] do_init_module+0x4a/0x210
    [<0000000087135ab5>] __do_sys_finit_module+0x93/0xf0
    [<000000004fcb1fa2>] do_syscall_64+0x34/0x80
    [<00000000c73c8d9d>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

with __init gone, that trace entry renders like:

    [<00000000ef738764>] kmemleak_test_init+<offset>/<size>

Link: https://lkml.kernel.org/r/20230525174356.69711-1-jim.cromie@gmail.com
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-06-09 16:25:40 -07:00

100 lines
2.6 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* samples/kmemleak/kmemleak-test.c
*
* Copyright (C) 2008 ARM Limited
* Written by Catalin Marinas <catalin.marinas@arm.com>
*/
#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 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");