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/* -*- linux-c -*-
* Memory allocation functions
* Copyright (C) 2005-2018 Red Hat Inc.
*
* This file is part of systemtap, and is free software. You can
* redistribute it and/or modify it under the terms of the GNU General
* Public License (GPL); either version 2, or (at your option) any
* later version.
*/
#ifndef _STAPLINUX_ALLOC_C_
#define _STAPLINUX_ALLOC_C_
#include <linux/percpu.h>
#include "stp_helper_lock.h"
static int _stp_allocated_net_memory = 0;
/* Default, and should be "safe" from anywhere. */
#define STP_ALLOC_FLAGS ((GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN) \
& ~__GFP_WAIT)
/* May only be used in context that can sleep. __GFP_NORETRY is to
suppress the oom-killer from kicking in. */
#define STP_ALLOC_SLEEP_FLAGS (GFP_KERNEL | __GFP_NORETRY)
/* #define DEBUG_MEMALLOC_MIGHT_SLEEP */
/*
* If DEBUG_MEMALLOC_MIGHT_SLEEP is defined (stap -DDEBUG_MEMALLOC_MIGHT_SLEEP ...)
* then all memory allocation operations are assumed to sleep. This
* can be used to check whether any memory allocations occur in atomic
* context, which is discouraged on realtime kernels. */
/* #define DEBUG_MEM */
/*
* If DEBUG_MEM is defined (stap -DDEBUG_MEM ...) then full memory
* tracking is used. Each allocation is recorded and matched with
* a free. Also a fence is set around the allocated memory so overflows
* and underflows can be detected. Errors are written to the system log
* with printk.
*
* NOTE: if youy system is slow or your script makes a very large number
* of allocations, you may get a warning in the system log:
* BUG: soft lockup - CPU#1 stuck for 11s! [staprun:28269]
* This is an expected side-effect of the overhead of tracking, especially
* with a simple linked list of allocations. Optimization
* would be nice, but DEBUG_MEM is only for testing.
*/
static int _stp_allocated_memory = 0;
#ifdef DEBUG_MEM
static STP_DEFINE_SPINLOCK(_stp_mem_lock);
#define MEM_MAGIC 0xc11cf77f
#define MEM_FENCE_SIZE 32
enum _stp_memtype { MEM_KMALLOC, MEM_VMALLOC, MEM_PERCPU };
typedef struct {
char *alloc;
char *free;
} _stp_malloc_type;
static const _stp_malloc_type _stp_malloc_types[] = {
{"kmalloc", "kfree"},
{"vmalloc", "vfree"},
{"alloc_percpu", "free_percpu"}
};
struct _stp_mem_entry {
struct list_head list;
int32_t magic;
enum _stp_memtype type;
size_t len;
void *addr;
};
#define MEM_DEBUG_SIZE (2*MEM_FENCE_SIZE+sizeof(struct _stp_mem_entry))
static LIST_HEAD(_stp_mem_list);
static void _stp_check_mem_fence (char *addr, int size)
{
char *ptr;
int i;
ptr = addr - MEM_FENCE_SIZE;
while (ptr < addr) {
if (*ptr != 0x55) {
printk("SYSTEMTAP ERROR: Memory fence corrupted before allocated memory\n");
printk("at addr %p. (Allocation starts at %p)", ptr, addr);
return;
}
ptr++;
}
ptr = addr + size;
while (ptr < addr + size + MEM_FENCE_SIZE) {
if (*ptr != 0x55) {
printk("SYSTEMTAP ERROR: Memory fence corrupted after allocated memory\n");
printk("at addr %p. (Allocation ends at %p)", ptr, addr + size - 1);
return;
}
ptr++;
}
}
static void *_stp_mem_debug_setup(void *addr, size_t size, enum _stp_memtype type)
{
struct list_head *p;
struct _stp_mem_entry *m;
unsigned long flags;
memset(addr, 0x55, MEM_FENCE_SIZE);
addr += MEM_FENCE_SIZE;
memset(addr + size, 0x55, MEM_FENCE_SIZE);
p = (struct list_head *)(addr + size + MEM_FENCE_SIZE);
m = (struct _stp_mem_entry *)p;
m->magic = MEM_MAGIC;
m->type = type;
m->len = size;
m->addr = addr;
stp_spin_lock_irqsave(&_stp_mem_lock, flags);
list_add(p, &_stp_mem_list);
stp_spin_unlock_irqrestore(&_stp_mem_lock, flags);
return addr;
}
/* Percpu allocations don't have the fence. Implementing it is problematic. */
static void _stp_mem_debug_percpu(struct _stp_mem_entry *m, void *addr, size_t size)
{
struct list_head *p = (struct list_head *)m;
unsigned long flags;
m->magic = MEM_MAGIC;
m->type = MEM_PERCPU;
m->len = size;
m->addr = addr;
stp_spin_lock_irqsave(&_stp_mem_lock, flags);
list_add(p, &_stp_mem_list);
stp_spin_unlock_irqrestore(&_stp_mem_lock, flags);
}
static void _stp_mem_debug_free(void *addr, enum _stp_memtype type)
{
int found = 0;
struct list_head *p, *tmp;
struct _stp_mem_entry *m = NULL;
unsigned long flags;
if (!addr) {
/* Passing NULL to these *free() functions is safe */
switch (type) {
case MEM_KMALLOC:
case MEM_PERCPU:
case MEM_VMALLOC:
return;
}
}
stp_spin_lock_irqsave(&_stp_mem_lock, flags);
list_for_each_safe(p, tmp, &_stp_mem_list) {
m = list_entry(p, struct _stp_mem_entry, list);
if (m->addr == addr) {
list_del(p);
found = 1;
break;
}
}
stp_spin_unlock_irqrestore(&_stp_mem_lock, flags);
if (!found) {
printk("SYSTEMTAP ERROR: Free of unallocated memory %p type=%s\n",
addr, _stp_malloc_types[type].free);
return;
}
if (m->magic != MEM_MAGIC) {
printk("SYSTEMTAP ERROR: Memory at %p corrupted!!\n", addr);
return;
}
if (m->type != type) {
printk("SYSTEMTAP ERROR: Memory allocated with %s and freed with %s\n",
_stp_malloc_types[m->type].alloc,
_stp_malloc_types[type].free);
}
switch (m->type) {
case MEM_KMALLOC:
_stp_check_mem_fence(addr, m->len);
kfree(addr - MEM_FENCE_SIZE);
break;
case MEM_PERCPU:
free_percpu(addr);
kfree(p);
break;
case MEM_VMALLOC:
_stp_check_mem_fence(addr, m->len);
vfree(addr - MEM_FENCE_SIZE);
break;
default:
printk("SYSTEMTAP ERROR: Attempted to free memory at addr %p len=%d with unknown allocation type.\n", addr, (int)m->len);
}
return;
}
static void _stp_mem_debug_validate(void *addr)
{
int found = 0;
struct list_head *p, *tmp;
struct _stp_mem_entry *m = NULL;
unsigned long flags;
stp_spin_lock_irqsave(&_stp_mem_lock, flags);
list_for_each_safe(p, tmp, &_stp_mem_list) {
m = list_entry(p, struct _stp_mem_entry, list);
if (m->addr == addr) {
found = 1;
break;
}
}
stp_spin_unlock_irqrestore(&_stp_mem_lock, flags);
if (!found) {
printk("SYSTEMTAP ERROR: Couldn't validate memory %p\n",
addr);
return;
}
if (m->magic != MEM_MAGIC) {
printk("SYSTEMTAP ERROR: Memory at %p corrupted!!\n", addr);
return;
}
switch (m->type) {
case MEM_KMALLOC:
_stp_check_mem_fence(addr, m->len);
break;
case MEM_PERCPU:
/* do nothing */
break;
case MEM_VMALLOC:
_stp_check_mem_fence(addr, m->len);
break;
default:
printk("SYSTEMTAP ERROR: Attempted to validate memory at addr %p len=%d with unknown allocation type.\n", addr, (int)m->len);
}
return;
}
#endif
/* #define STP_MAXMEMORY 8192 */
/*
* If STP_MAXMEMORY is defined to a value (stap -DSTP_MAXMEMORY=8192
* ...) then every memory allocation is checked to make sure the
* systemtap module doesn't use more than STP_MAXMEMORY of memory.
* STP_MAXMEMORY is specified in kilobytes, so, for example, '8192'
* means that the systemtap module won't use more than 8 megabytes of
* memory.
*
* Note 1: This size does include the size of the module itself, plus
* any additional allocations.
*
* Note 2: Since we can't be ensured that the module transport is set
* up when a memory allocation problem happens, this code can't
* directly report an error back to a user (so instead it uses
* 'printk'). If the modules transport has been set up, the code that
* calls the memory allocation functions
* (_stp_kmalloc/_stp_kzalloc/etc.) should report an error directly to
* the user.
*
* Note 3: This only tracks direct allocations by the systemtap
* runtime. This does not track indirect allocations (such as done by
* kprobes/uprobes/etc. internals).
*/
#ifdef STP_MAXMEMORY
#ifdef STAPCONF_MODULE_LAYOUT
#define _STP_MODULE_CORE_SIZE (THIS_MODULE->core_layout.size)
#elif defined(STAPCONF_GRSECURITY)
#define _STP_MODULE_CORE_SIZE (THIS_MODULE->core_size_rw)
#else
#define _STP_MODULE_CORE_SIZE (THIS_MODULE->core_size)
#endif
#endif
static void *_stp_kmalloc_gfp(size_t size, gfp_t gfp_mask)
{
void *ret;
#ifdef DEBUG_MEMALLOC_MIGHT_SLEEP
might_sleep();
#endif
#ifdef STP_MAXMEMORY
if ((_STP_MODULE_CORE_SIZE + _stp_allocated_memory + size)
> (STP_MAXMEMORY * 1024)) {
return NULL;
}
#endif
#ifdef DEBUG_MEM
ret = kmalloc(size + MEM_DEBUG_SIZE, gfp_mask);
if (likely(ret)) {
_stp_allocated_memory += size;
ret = _stp_mem_debug_setup(ret, size, MEM_KMALLOC);
}
#else
ret = kmalloc(size, gfp_mask);
if (likely(ret)) {
_stp_allocated_memory += size;
}
#endif
return ret;
}
static void *_stp_kmalloc(size_t size)
{
return _stp_kmalloc_gfp(size, STP_ALLOC_FLAGS);
}
static void *_stp_kzalloc_gfp(size_t size, gfp_t gfp_mask)
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15)
{
void *ret;
#ifdef STP_MAXMEMORY
if ((_STP_MODULE_CORE_SIZE + _stp_allocated_memory + size)
> (STP_MAXMEMORY * 1024)) {
return NULL;
}
#endif
#ifdef DEBUG_MEM
ret = kmalloc(size + MEM_DEBUG_SIZE, gfp_mask);
if (likely(ret)) {
_stp_allocated_memory += size;
ret = _stp_mem_debug_setup(ret, size, MEM_KMALLOC);
memset (ret, 0, size);
}
#else
ret = kmalloc(size, gfp_mask);
if (likely(ret)) {
_stp_allocated_memory += size;
memset (ret, 0, size);
}
#endif /* DEBUG_MEM */
return ret;
}
#else /* LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,15) */
{
void *ret;
#ifdef STP_MAXMEMORY
if ((_STP_MODULE_CORE_SIZE + _stp_allocated_memory + size)
> (STP_MAXMEMORY * 1024)) {
return NULL;
}
#endif
#ifdef DEBUG_MEM
ret = kzalloc(size + MEM_DEBUG_SIZE, gfp_mask);
if (likely(ret)) {
_stp_allocated_memory += size;
ret = _stp_mem_debug_setup(ret, size, MEM_KMALLOC);
}
#else
ret = kzalloc(size, gfp_mask);
if (likely(ret)) {
_stp_allocated_memory += size;
}
#endif
return ret;
}
#endif /* LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15) */
static void *_stp_kzalloc(size_t size)
{
return _stp_kzalloc_gfp(size, STP_ALLOC_FLAGS);
}
#ifndef STAPCONF_VZALLOC
static void *vzalloc(unsigned long size)
{
void *ret = vmalloc(size);
if (ret)
memset(ret, 0, size);
return ret;
}
#endif
static void *_stp_vzalloc(size_t size)
{
void *ret;
#ifdef STP_MAXMEMORY
if ((_STP_MODULE_CORE_SIZE + _stp_allocated_memory + size)
> (STP_MAXMEMORY * 1024)) {
return NULL;
}
#endif
#ifdef DEBUG_MEM
ret = vzalloc(size + MEM_DEBUG_SIZE);
if (likely(ret)) {
_stp_allocated_memory += size;
ret = _stp_mem_debug_setup(ret, size, MEM_VMALLOC);
}
#else
ret = vzalloc(size);
if (likely(ret)) {
_stp_allocated_memory += size;
}
#endif
return ret;
}
#ifndef STAPCONF_VMALLOC_NODE
static void *vmalloc_node(unsigned long size, int node __attribute__((unused)))
{
return vmalloc(size);
}
#endif
#ifndef STAPCONF_VZALLOC_NODE
static void *vzalloc_node(unsigned long size, int node)
{
void *ret = vmalloc_node(size, node);
if (ret)
memset(ret, 0, size);
return ret;
}
#endif
static void *_stp_vzalloc_node(size_t size, int node)
{
void *ret;
#ifdef STP_MAXMEMORY
if ((_STP_MODULE_CORE_SIZE + _stp_allocated_memory + size)
> (STP_MAXMEMORY * 1024)) {
return NULL;
}
#endif
#ifdef DEBUG_MEM
ret = vzalloc_node(size + MEM_DEBUG_SIZE, node);
if (likely(ret)) {
_stp_allocated_memory += size;
ret = _stp_mem_debug_setup(ret, size, MEM_VMALLOC);
}
#else
ret = vzalloc_node(size, node);
if (likely(ret)) {
_stp_allocated_memory += size;
}
#endif
return ret;
}
#ifdef PCPU_MIN_UNIT_SIZE
#define _STP_MAX_PERCPU_SIZE PCPU_MIN_UNIT_SIZE
#else
#define _STP_MAX_PERCPU_SIZE 131072
#endif
/* Note, calls __alloc_percpu which may sleep and always uses GFP_KERNEL. */
static void *_stp_alloc_percpu(size_t size)
{
void *ret;
if (size > _STP_MAX_PERCPU_SIZE)
return NULL;
#ifdef STP_MAXMEMORY
if ((_STP_MODULE_CORE_SIZE + _stp_allocated_memory
+ (size * num_online_cpus()))
> (STP_MAXMEMORY * 1024)) {
return NULL;
}
#endif
#ifdef STAPCONF_ALLOC_PERCPU_ALIGN
ret = __alloc_percpu(size, 8);
#else
ret = __alloc_percpu(size);
#endif
#ifdef DEBUG_MEM
if (likely(ret)) {
struct _stp_mem_entry *m = kmalloc(sizeof(struct _stp_mem_entry), GFP_KERNEL);
if (unlikely(m == NULL)) {
free_percpu(ret);
return NULL;
}
_stp_allocated_memory += size * num_online_cpus();
_stp_mem_debug_percpu(m, ret, size);
}
#else
if (likely(ret)) {
_stp_allocated_memory += size * num_online_cpus();
}
#endif
return ret;
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,12)
#define _stp_kmalloc_node(size,node) _stp_kmalloc(size)
#define _stp_kmalloc_node_gfp(size,node,gfp) _stp_kmalloc_gfp(size,gfp)
#define _stp_kzalloc_node(size,node) _stp_kzalloc(size)
#define _stp_kzalloc_node_gfp(size,node,gfp) _stp_kzalloc_gfp(size,gfp)
#else
static void *_stp_kmalloc_node_gfp(size_t size, int node, gfp_t gfp_mask)
{
void *ret;
#ifdef DEBUG_MEMALLOC_MIGHT_SLEEP
might_sleep();
#endif
#ifdef STP_MAXMEMORY
if ((_STP_MODULE_CORE_SIZE + _stp_allocated_memory + size)
> (STP_MAXMEMORY * 1024)) {
return NULL;
}
#endif
#ifdef DEBUG_MEM
ret = kmalloc_node(size + MEM_DEBUG_SIZE, gfp_mask, node);
if (likely(ret)) {
_stp_allocated_memory += size;
ret = _stp_mem_debug_setup(ret, size, MEM_KMALLOC);
}
#else
ret = kmalloc_node(size, gfp_mask, node);
if (likely(ret)) {
_stp_allocated_memory += size;
}
#endif
return ret;
}
static void *_stp_kzalloc_node_gfp(size_t size, int node, gfp_t gfp_mask)
{
/* This used to be simply:
* return _stp_kmalloc_node_gfp(size, node, gfp_mask | __GFP_ZERO);
* but rhel5-era kernels BUG out on that flag. (PR14957)
*
* We could make a big #if-alternation for kernels which have support
* for kzalloc_node (kernel commit 979b0fea), as in _stp_kzalloc_gfp,
* but IMO that's needlessly complex.
*
* So for now, just malloc and zero it manually.
*/
void *ret = _stp_kmalloc_node_gfp(size, node, gfp_mask);
#ifdef DEBUG_MEMALLOC_MIGHT_SLEEP
might_sleep();
#endif
if (likely(ret)) {
memset (ret, 0, size);
}
return ret;
}
static void *_stp_kmalloc_node(size_t size, int node)
{
return _stp_kmalloc_node_gfp(size, node, STP_ALLOC_FLAGS);
}
static void *_stp_kzalloc_node(size_t size, int node)
{
return _stp_kzalloc_node_gfp(size, node, STP_ALLOC_FLAGS);
}
#endif /* LINUX_VERSION_CODE */
static void _stp_kfree(void *addr)
{
#ifdef DEBUG_MEMALLOC_MIGHT_SLEEP
might_sleep();
#endif
#ifdef DEBUG_MEM
_stp_mem_debug_free(addr, MEM_KMALLOC);
#else
kfree(addr);
#endif
}
static void _stp_vfree(void *addr)
{
#ifdef DEBUG_MEMALLOC_MIGHT_SLEEP
might_sleep();
#endif
#ifdef DEBUG_MEM
_stp_mem_debug_free(addr, MEM_VMALLOC);
#else
vfree(addr);
#endif
}
static void _stp_free_percpu(void *addr)
{
#ifdef DEBUG_MEMALLOC_MIGHT_SLEEP
might_sleep();
#endif
#ifdef DEBUG_MEM
_stp_mem_debug_free(addr, MEM_PERCPU);
#else
free_percpu(addr);
#endif
}
static void _stp_mem_debug_done(void)
{
#ifdef DEBUG_MEM
struct list_head *p, *tmp;
struct _stp_mem_entry *m;
unsigned long flags;
stp_spin_lock_irqsave(&_stp_mem_lock, flags);
list_for_each_safe(p, tmp, &_stp_mem_list) {
m = list_entry(p, struct _stp_mem_entry, list);
list_del(p);
printk("SYSTEMTAP ERROR: Memory %p len=%d allocation type: %s. Not freed.\n",
m->addr, (int)m->len, _stp_malloc_types[m->type].alloc);
if (m->magic != MEM_MAGIC) {
printk("SYSTEMTAP ERROR: Memory at %p len=%d corrupted!!\n", m->addr, (int)m->len);
/* Don't free. Too dangerous */
goto done;
}
switch (m->type) {
case MEM_KMALLOC:
_stp_check_mem_fence(m->addr, m->len);
kfree(m->addr - MEM_FENCE_SIZE);
break;
case MEM_PERCPU:
free_percpu(m->addr);
kfree(p);
break;
case MEM_VMALLOC:
_stp_check_mem_fence(m->addr, m->len);
vfree(m->addr - MEM_FENCE_SIZE);
break;
default:
printk("SYSTEMTAP ERROR: Attempted to free memory at addr %p len=%d with unknown allocation type.\n", m->addr, (int)m->len);
}
}
done:
stp_spin_unlock_irqrestore(&_stp_mem_lock, flags);
return;
#endif
}
#endif /* _STAPLINUX_ALLOC_C_ */