Contributors: 119
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Davi Arnaut |
189 |
4.98% |
1 |
0.43% |
| Daniel Jordan |
188 |
4.95% |
1 |
0.43% |
| William Roberts |
184 |
4.85% |
1 |
0.43% |
| Al Viro |
158 |
4.16% |
7 |
3.03% |
| Catalin Marinas |
148 |
3.90% |
3 |
1.30% |
| Matthew Wilcox |
145 |
3.82% |
9 |
3.90% |
| Kees Cook |
133 |
3.50% |
9 |
3.90% |
| Jerome Marchand |
131 |
3.45% |
2 |
0.87% |
| Paolo Bonzini |
119 |
3.13% |
1 |
0.43% |
| Alexandre Ghiti |
118 |
3.11% |
5 |
2.16% |
| Alexey Dobriyan |
114 |
3.00% |
3 |
1.30% |
| Paulo Marques |
112 |
2.95% |
1 |
0.43% |
| Feng Tang |
92 |
2.42% |
2 |
0.87% |
| Michal Hocko |
89 |
2.34% |
7 |
3.03% |
| Linus Torvalds (pre-git) |
87 |
2.29% |
19 |
8.23% |
| Li Zefan |
80 |
2.11% |
1 |
0.43% |
| Kefeng Wang |
79 |
2.08% |
2 |
0.87% |
| Paul E. McKenney |
68 |
1.79% |
5 |
2.16% |
| David Hildenbrand |
67 |
1.76% |
2 |
0.87% |
| Jason A. Donenfeld |
67 |
1.76% |
1 |
0.43% |
| Song Liu |
66 |
1.74% |
2 |
0.87% |
| David Chinner |
63 |
1.66% |
1 |
0.43% |
| Andrzej Hajda |
62 |
1.63% |
1 |
0.43% |
| Yoshinori Sato |
57 |
1.50% |
1 |
0.43% |
| Jeremy Fitzhardinge |
49 |
1.29% |
1 |
0.43% |
| Waiman Long |
45 |
1.19% |
2 |
0.87% |
| Arnaldo Carvalho de Melo |
42 |
1.11% |
1 |
0.43% |
| Andrew Shewmaker |
42 |
1.11% |
2 |
0.87% |
| Kirill A. Shutemov |
40 |
1.05% |
2 |
0.87% |
| Linus Torvalds |
36 |
0.95% |
5 |
2.16% |
| Shaohua Li |
36 |
0.95% |
3 |
1.30% |
| Christoph Hellwig |
36 |
0.95% |
3 |
1.30% |
| Siddhesh Poyarekar |
35 |
0.92% |
1 |
0.43% |
| Daniel Cashman |
34 |
0.90% |
3 |
1.30% |
| Alexey Kardashevskiy |
33 |
0.87% |
4 |
1.73% |
| Andrew Morton |
32 |
0.84% |
6 |
2.60% |
| Christian König |
32 |
0.84% |
1 |
0.43% |
| Alan Cox |
30 |
0.79% |
3 |
1.30% |
| kartik |
27 |
0.71% |
1 |
0.43% |
| Helge Deller |
26 |
0.68% |
2 |
0.87% |
| Michel Lespinasse |
24 |
0.63% |
5 |
2.16% |
| Joe Perches |
24 |
0.63% |
1 |
0.43% |
| Mike Rapoport |
24 |
0.63% |
3 |
1.30% |
| Rik Van Riel |
23 |
0.61% |
1 |
0.43% |
| Jaroslav Kysela |
22 |
0.58% |
2 |
0.87% |
| Rick Edgecombe |
21 |
0.55% |
1 |
0.43% |
| Mateusz Guzik |
20 |
0.53% |
1 |
0.43% |
| David Howells |
19 |
0.50% |
3 |
1.30% |
| K. Y. Srinivasan |
19 |
0.50% |
1 |
0.43% |
| Hideaki Yoshifuji / 吉藤英明 |
19 |
0.50% |
2 |
0.87% |
| Suren Baghdasaryan |
15 |
0.40% |
2 |
0.87% |
| Ingo Molnar |
14 |
0.37% |
4 |
1.73% |
| Eric W. Biedermann |
14 |
0.37% |
3 |
1.30% |
| Andrey Ryabinin |
14 |
0.37% |
2 |
0.87% |
| Matthew Cassell |
13 |
0.34% |
1 |
0.43% |
| Jason Cooper |
13 |
0.34% |
2 |
0.87% |
| Johannes Weiner |
13 |
0.34% |
2 |
0.87% |
| Daniel Borkmann |
13 |
0.34% |
1 |
0.43% |
| Florian Westphal |
12 |
0.32% |
1 |
0.43% |
| Serge E. Hallyn |
12 |
0.32% |
1 |
0.43% |
| Mike Frysinger |
12 |
0.32% |
1 |
0.43% |
| Andrea Arcangeli |
11 |
0.29% |
2 |
0.87% |
| Hugh Dickins |
11 |
0.29% |
1 |
0.43% |
| Christoph Lameter |
10 |
0.26% |
3 |
1.30% |
| Arjan van de Ven |
10 |
0.26% |
2 |
0.87% |
| Rusty Russell |
9 |
0.24% |
1 |
0.43% |
| Frank Hirtz |
9 |
0.24% |
1 |
0.43% |
| Kent Overstreet |
9 |
0.24% |
1 |
0.43% |
| John Johansen |
9 |
0.24% |
1 |
0.43% |
| Chris Wilson |
9 |
0.24% |
2 |
0.87% |
| Hao Sun |
9 |
0.24% |
1 |
0.43% |
| Mikulas Patocka |
8 |
0.21% |
1 |
0.43% |
| Oleg Nesterov |
8 |
0.21% |
1 |
0.43% |
| Chen Jun |
8 |
0.21% |
1 |
0.43% |
| Andrew Lutomirski |
7 |
0.18% |
1 |
0.43% |
| Nicholas Piggin |
7 |
0.18% |
2 |
0.87% |
| Srikar Dronamraju |
6 |
0.16% |
1 |
0.43% |
| Matt Mackall |
6 |
0.16% |
1 |
0.43% |
| MinChan Kim |
6 |
0.16% |
1 |
0.43% |
| Greg Ungerer |
5 |
0.13% |
1 |
0.43% |
| Zqiang |
5 |
0.13% |
1 |
0.43% |
| Motohiro Kosaki |
5 |
0.13% |
1 |
0.43% |
| Julia Lawall |
5 |
0.13% |
1 |
0.43% |
| Michal Koutný |
4 |
0.11% |
1 |
0.43% |
| Alexander Graf |
4 |
0.11% |
1 |
0.43% |
| Fabio De Francesco |
4 |
0.11% |
1 |
0.43% |
| Alexander Kuleshov |
3 |
0.08% |
1 |
0.43% |
| Adrian Bunk |
3 |
0.08% |
1 |
0.43% |
| Neil Brown |
3 |
0.08% |
1 |
0.43% |
| Theodore Y. Ts'o |
3 |
0.08% |
1 |
0.43% |
| Jean-Philippe Brucker |
3 |
0.08% |
1 |
0.43% |
| Roman Gushchin |
3 |
0.08% |
1 |
0.43% |
| Gideon Israel Dsouza |
3 |
0.08% |
1 |
0.43% |
| Joel Granados |
3 |
0.08% |
1 |
0.43% |
| Andy Whitcroft |
2 |
0.05% |
1 |
0.43% |
| Yu-cheng Yu |
2 |
0.05% |
1 |
0.43% |
| Eduard - Gabriel Munteanu |
2 |
0.05% |
1 |
0.43% |
| Daniel Vetter |
2 |
0.05% |
1 |
0.43% |
| Scott Wood |
2 |
0.05% |
1 |
0.43% |
| Pekka J Enberg |
2 |
0.05% |
1 |
0.43% |
| Miles Chen |
2 |
0.05% |
1 |
0.43% |
| Hideo Aoki |
2 |
0.05% |
1 |
0.43% |
| Alex Williamson |
2 |
0.05% |
1 |
0.43% |
| ZhangPeng |
2 |
0.05% |
1 |
0.43% |
| Aneesh Kumar K.V |
2 |
0.05% |
1 |
0.43% |
| Lorenzo Stoakes |
2 |
0.05% |
1 |
0.43% |
| Roland McGrath |
2 |
0.05% |
1 |
0.43% |
| Bartosz Golaszewski |
1 |
0.03% |
1 |
0.43% |
| Zhen Lei |
1 |
0.03% |
1 |
0.43% |
| Christophe Leroy |
1 |
0.03% |
1 |
0.43% |
| Thomas Gleixner |
1 |
0.03% |
1 |
0.43% |
| Peter Collingbourne |
1 |
0.03% |
1 |
0.43% |
| Andries E. Brouwer |
1 |
0.03% |
1 |
0.43% |
| Arun K S |
1 |
0.03% |
1 |
0.43% |
| Bhaskar Chowdhury |
1 |
0.03% |
1 |
0.43% |
| Paul Gortmaker |
1 |
0.03% |
1 |
0.43% |
| Johannes Thumshirn |
1 |
0.03% |
1 |
0.43% |
| Maninder Singh |
1 |
0.03% |
1 |
0.43% |
| Jesper Juhl |
1 |
0.03% |
1 |
0.43% |
| Total |
3797 |
|
231 |
|
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/compiler.h>
#include <linux/export.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/sched/signal.h>
#include <linux/sched/task_stack.h>
#include <linux/security.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/mman.h>
#include <linux/hugetlb.h>
#include <linux/vmalloc.h>
#include <linux/userfaultfd_k.h>
#include <linux/elf.h>
#include <linux/elf-randomize.h>
#include <linux/personality.h>
#include <linux/random.h>
#include <linux/processor.h>
#include <linux/sizes.h>
#include <linux/compat.h>
#include <linux/uaccess.h>
#include <kunit/visibility.h>
#include "internal.h"
#include "swap.h"
/**
* kfree_const - conditionally free memory
* @x: pointer to the memory
*
* Function calls kfree only if @x is not in .rodata section.
*/
void kfree_const(const void *x)
{
if (!is_kernel_rodata((unsigned long)x))
kfree(x);
}
EXPORT_SYMBOL(kfree_const);
/**
* kstrdup - allocate space for and copy an existing string
* @s: the string to duplicate
* @gfp: the GFP mask used in the kmalloc() call when allocating memory
*
* Return: newly allocated copy of @s or %NULL in case of error
*/
noinline
char *kstrdup(const char *s, gfp_t gfp)
{
size_t len;
char *buf;
if (!s)
return NULL;
len = strlen(s) + 1;
buf = kmalloc_track_caller(len, gfp);
if (buf)
memcpy(buf, s, len);
return buf;
}
EXPORT_SYMBOL(kstrdup);
/**
* kstrdup_const - conditionally duplicate an existing const string
* @s: the string to duplicate
* @gfp: the GFP mask used in the kmalloc() call when allocating memory
*
* Note: Strings allocated by kstrdup_const should be freed by kfree_const and
* must not be passed to krealloc().
*
* Return: source string if it is in .rodata section otherwise
* fallback to kstrdup.
*/
const char *kstrdup_const(const char *s, gfp_t gfp)
{
if (is_kernel_rodata((unsigned long)s))
return s;
return kstrdup(s, gfp);
}
EXPORT_SYMBOL(kstrdup_const);
/**
* kstrndup - allocate space for and copy an existing string
* @s: the string to duplicate
* @max: read at most @max chars from @s
* @gfp: the GFP mask used in the kmalloc() call when allocating memory
*
* Note: Use kmemdup_nul() instead if the size is known exactly.
*
* Return: newly allocated copy of @s or %NULL in case of error
*/
char *kstrndup(const char *s, size_t max, gfp_t gfp)
{
size_t len;
char *buf;
if (!s)
return NULL;
len = strnlen(s, max);
buf = kmalloc_track_caller(len+1, gfp);
if (buf) {
memcpy(buf, s, len);
buf[len] = '\0';
}
return buf;
}
EXPORT_SYMBOL(kstrndup);
/**
* kmemdup - duplicate region of memory
*
* @src: memory region to duplicate
* @len: memory region length
* @gfp: GFP mask to use
*
* Return: newly allocated copy of @src or %NULL in case of error,
* result is physically contiguous. Use kfree() to free.
*/
void *kmemdup_noprof(const void *src, size_t len, gfp_t gfp)
{
void *p;
p = kmalloc_node_track_caller_noprof(len, gfp, NUMA_NO_NODE, _RET_IP_);
if (p)
memcpy(p, src, len);
return p;
}
EXPORT_SYMBOL(kmemdup_noprof);
/**
* kmemdup_array - duplicate a given array.
*
* @src: array to duplicate.
* @count: number of elements to duplicate from array.
* @element_size: size of each element of array.
* @gfp: GFP mask to use.
*
* Return: duplicated array of @src or %NULL in case of error,
* result is physically contiguous. Use kfree() to free.
*/
void *kmemdup_array(const void *src, size_t count, size_t element_size, gfp_t gfp)
{
return kmemdup(src, size_mul(element_size, count), gfp);
}
EXPORT_SYMBOL(kmemdup_array);
/**
* kvmemdup - duplicate region of memory
*
* @src: memory region to duplicate
* @len: memory region length
* @gfp: GFP mask to use
*
* Return: newly allocated copy of @src or %NULL in case of error,
* result may be not physically contiguous. Use kvfree() to free.
*/
void *kvmemdup(const void *src, size_t len, gfp_t gfp)
{
void *p;
p = kvmalloc(len, gfp);
if (p)
memcpy(p, src, len);
return p;
}
EXPORT_SYMBOL(kvmemdup);
/**
* kmemdup_nul - Create a NUL-terminated string from unterminated data
* @s: The data to stringify
* @len: The size of the data
* @gfp: the GFP mask used in the kmalloc() call when allocating memory
*
* Return: newly allocated copy of @s with NUL-termination or %NULL in
* case of error
*/
char *kmemdup_nul(const char *s, size_t len, gfp_t gfp)
{
char *buf;
if (!s)
return NULL;
buf = kmalloc_track_caller(len + 1, gfp);
if (buf) {
memcpy(buf, s, len);
buf[len] = '\0';
}
return buf;
}
EXPORT_SYMBOL(kmemdup_nul);
static kmem_buckets *user_buckets __ro_after_init;
static int __init init_user_buckets(void)
{
user_buckets = kmem_buckets_create("memdup_user", 0, 0, INT_MAX, NULL);
return 0;
}
subsys_initcall(init_user_buckets);
/**
* memdup_user - duplicate memory region from user space
*
* @src: source address in user space
* @len: number of bytes to copy
*
* Return: an ERR_PTR() on failure. Result is physically
* contiguous, to be freed by kfree().
*/
void *memdup_user(const void __user *src, size_t len)
{
void *p;
p = kmem_buckets_alloc_track_caller(user_buckets, len, GFP_USER | __GFP_NOWARN);
if (!p)
return ERR_PTR(-ENOMEM);
if (copy_from_user(p, src, len)) {
kfree(p);
return ERR_PTR(-EFAULT);
}
return p;
}
EXPORT_SYMBOL(memdup_user);
/**
* vmemdup_user - duplicate memory region from user space
*
* @src: source address in user space
* @len: number of bytes to copy
*
* Return: an ERR_PTR() on failure. Result may be not
* physically contiguous. Use kvfree() to free.
*/
void *vmemdup_user(const void __user *src, size_t len)
{
void *p;
p = kmem_buckets_valloc(user_buckets, len, GFP_USER);
if (!p)
return ERR_PTR(-ENOMEM);
if (copy_from_user(p, src, len)) {
kvfree(p);
return ERR_PTR(-EFAULT);
}
return p;
}
EXPORT_SYMBOL(vmemdup_user);
/**
* strndup_user - duplicate an existing string from user space
* @s: The string to duplicate
* @n: Maximum number of bytes to copy, including the trailing NUL.
*
* Return: newly allocated copy of @s or an ERR_PTR() in case of error
*/
char *strndup_user(const char __user *s, long n)
{
char *p;
long length;
length = strnlen_user(s, n);
if (!length)
return ERR_PTR(-EFAULT);
if (length > n)
return ERR_PTR(-EINVAL);
p = memdup_user(s, length);
if (IS_ERR(p))
return p;
p[length - 1] = '\0';
return p;
}
EXPORT_SYMBOL(strndup_user);
/**
* memdup_user_nul - duplicate memory region from user space and NUL-terminate
*
* @src: source address in user space
* @len: number of bytes to copy
*
* Return: an ERR_PTR() on failure.
*/
void *memdup_user_nul(const void __user *src, size_t len)
{
char *p;
/*
* Always use GFP_KERNEL, since copy_from_user() can sleep and
* cause pagefault, which makes it pointless to use GFP_NOFS
* or GFP_ATOMIC.
*/
p = kmalloc_track_caller(len + 1, GFP_KERNEL);
if (!p)
return ERR_PTR(-ENOMEM);
if (copy_from_user(p, src, len)) {
kfree(p);
return ERR_PTR(-EFAULT);
}
p[len] = '\0';
return p;
}
EXPORT_SYMBOL(memdup_user_nul);
/* Check if the vma is being used as a stack by this task */
int vma_is_stack_for_current(struct vm_area_struct *vma)
{
struct task_struct * __maybe_unused t = current;
return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t));
}
/*
* Change backing file, only valid to use during initial VMA setup.
*/
void vma_set_file(struct vm_area_struct *vma, struct file *file)
{
/* Changing an anonymous vma with this is illegal */
get_file(file);
swap(vma->vm_file, file);
fput(file);
}
EXPORT_SYMBOL(vma_set_file);
#ifndef STACK_RND_MASK
#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12)) /* 8MB of VA */
#endif
unsigned long randomize_stack_top(unsigned long stack_top)
{
unsigned long random_variable = 0;
if (current->flags & PF_RANDOMIZE) {
random_variable = get_random_long();
random_variable &= STACK_RND_MASK;
random_variable <<= PAGE_SHIFT;
}
#ifdef CONFIG_STACK_GROWSUP
return PAGE_ALIGN(stack_top) + random_variable;
#else
return PAGE_ALIGN(stack_top) - random_variable;
#endif
}
/**
* randomize_page - Generate a random, page aligned address
* @start: The smallest acceptable address the caller will take.
* @range: The size of the area, starting at @start, within which the
* random address must fall.
*
* If @start + @range would overflow, @range is capped.
*
* NOTE: Historical use of randomize_range, which this replaces, presumed that
* @start was already page aligned. We now align it regardless.
*
* Return: A page aligned address within [start, start + range). On error,
* @start is returned.
*/
unsigned long randomize_page(unsigned long start, unsigned long range)
{
if (!PAGE_ALIGNED(start)) {
range -= PAGE_ALIGN(start) - start;
start = PAGE_ALIGN(start);
}
if (start > ULONG_MAX - range)
range = ULONG_MAX - start;
range >>= PAGE_SHIFT;
if (range == 0)
return start;
return start + (get_random_long() % range << PAGE_SHIFT);
}
#ifdef CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
unsigned long __weak arch_randomize_brk(struct mm_struct *mm)
{
/* Is the current task 32bit ? */
if (!IS_ENABLED(CONFIG_64BIT) || is_compat_task())
return randomize_page(mm->brk, SZ_32M);
return randomize_page(mm->brk, SZ_1G);
}
unsigned long arch_mmap_rnd(void)
{
unsigned long rnd;
#ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
if (is_compat_task())
rnd = get_random_long() & ((1UL << mmap_rnd_compat_bits) - 1);
else
#endif /* CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS */
rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1);
return rnd << PAGE_SHIFT;
}
static int mmap_is_legacy(struct rlimit *rlim_stack)
{
if (current->personality & ADDR_COMPAT_LAYOUT)
return 1;
/* On parisc the stack always grows up - so a unlimited stack should
* not be an indicator to use the legacy memory layout. */
if (rlim_stack->rlim_cur == RLIM_INFINITY &&
!IS_ENABLED(CONFIG_STACK_GROWSUP))
return 1;
return sysctl_legacy_va_layout;
}
/*
* Leave enough space between the mmap area and the stack to honour ulimit in
* the face of randomisation.
*/
#define MIN_GAP (SZ_128M)
#define MAX_GAP (STACK_TOP / 6 * 5)
static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack)
{
#ifdef CONFIG_STACK_GROWSUP
/*
* For an upwards growing stack the calculation is much simpler.
* Memory for the maximum stack size is reserved at the top of the
* task. mmap_base starts directly below the stack and grows
* downwards.
*/
return PAGE_ALIGN_DOWN(mmap_upper_limit(rlim_stack) - rnd);
#else
unsigned long gap = rlim_stack->rlim_cur;
unsigned long pad = stack_guard_gap;
/* Account for stack randomization if necessary */
if (current->flags & PF_RANDOMIZE)
pad += (STACK_RND_MASK << PAGE_SHIFT);
/* Values close to RLIM_INFINITY can overflow. */
if (gap + pad > gap)
gap += pad;
if (gap < MIN_GAP)
gap = MIN_GAP;
else if (gap > MAX_GAP)
gap = MAX_GAP;
return PAGE_ALIGN(STACK_TOP - gap - rnd);
#endif
}
void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
{
unsigned long random_factor = 0UL;
if (current->flags & PF_RANDOMIZE)
random_factor = arch_mmap_rnd();
if (mmap_is_legacy(rlim_stack)) {
mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
clear_bit(MMF_TOPDOWN, &mm->flags);
} else {
mm->mmap_base = mmap_base(random_factor, rlim_stack);
set_bit(MMF_TOPDOWN, &mm->flags);
}
}
#elif defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
{
mm->mmap_base = TASK_UNMAPPED_BASE;
clear_bit(MMF_TOPDOWN, &mm->flags);
}
#endif
#ifdef CONFIG_MMU
EXPORT_SYMBOL_IF_KUNIT(arch_pick_mmap_layout);
#endif
/**
* __account_locked_vm - account locked pages to an mm's locked_vm
* @mm: mm to account against
* @pages: number of pages to account
* @inc: %true if @pages should be considered positive, %false if not
* @task: task used to check RLIMIT_MEMLOCK
* @bypass_rlim: %true if checking RLIMIT_MEMLOCK should be skipped
*
* Assumes @task and @mm are valid (i.e. at least one reference on each), and
* that mmap_lock is held as writer.
*
* Return:
* * 0 on success
* * -ENOMEM if RLIMIT_MEMLOCK would be exceeded.
*/
int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc,
struct task_struct *task, bool bypass_rlim)
{
unsigned long locked_vm, limit;
int ret = 0;
mmap_assert_write_locked(mm);
locked_vm = mm->locked_vm;
if (inc) {
if (!bypass_rlim) {
limit = task_rlimit(task, RLIMIT_MEMLOCK) >> PAGE_SHIFT;
if (locked_vm + pages > limit)
ret = -ENOMEM;
}
if (!ret)
mm->locked_vm = locked_vm + pages;
} else {
WARN_ON_ONCE(pages > locked_vm);
mm->locked_vm = locked_vm - pages;
}
pr_debug("%s: [%d] caller %ps %c%lu %lu/%lu%s\n", __func__, task->pid,
(void *)_RET_IP_, (inc) ? '+' : '-', pages << PAGE_SHIFT,
locked_vm << PAGE_SHIFT, task_rlimit(task, RLIMIT_MEMLOCK),
ret ? " - exceeded" : "");
return ret;
}
EXPORT_SYMBOL_GPL(__account_locked_vm);
/**
* account_locked_vm - account locked pages to an mm's locked_vm
* @mm: mm to account against, may be NULL
* @pages: number of pages to account
* @inc: %true if @pages should be considered positive, %false if not
*
* Assumes a non-NULL @mm is valid (i.e. at least one reference on it).
*
* Return:
* * 0 on success, or if mm is NULL
* * -ENOMEM if RLIMIT_MEMLOCK would be exceeded.
*/
int account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc)
{
int ret;
if (pages == 0 || !mm)
return 0;
mmap_write_lock(mm);
ret = __account_locked_vm(mm, pages, inc, current,
capable(CAP_IPC_LOCK));
mmap_write_unlock(mm);
return ret;
}
EXPORT_SYMBOL_GPL(account_locked_vm);
unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr,
unsigned long len, unsigned long prot,
unsigned long flag, unsigned long pgoff)
{
unsigned long ret;
struct mm_struct *mm = current->mm;
unsigned long populate;
LIST_HEAD(uf);
ret = security_mmap_file(file, prot, flag);
if (!ret) {
if (mmap_write_lock_killable(mm))
return -EINTR;
ret = do_mmap(file, addr, len, prot, flag, 0, pgoff, &populate,
&uf);
mmap_write_unlock(mm);
userfaultfd_unmap_complete(mm, &uf);
if (populate)
mm_populate(ret, populate);
}
return ret;
}
unsigned long vm_mmap(struct file *file, unsigned long addr,
unsigned long len, unsigned long prot,
unsigned long flag, unsigned long offset)
{
if (unlikely(offset + PAGE_ALIGN(len) < offset))
return -EINVAL;
if (unlikely(offset_in_page(offset)))
return -EINVAL;
return vm_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
}
EXPORT_SYMBOL(vm_mmap);
/**
* __kvmalloc_node - attempt to allocate physically contiguous memory, but upon
* failure, fall back to non-contiguous (vmalloc) allocation.
* @size: size of the request.
* @b: which set of kmalloc buckets to allocate from.
* @flags: gfp mask for the allocation - must be compatible (superset) with GFP_KERNEL.
* @node: numa node to allocate from
*
* Uses kmalloc to get the memory but if the allocation fails then falls back
* to the vmalloc allocator. Use kvfree for freeing the memory.
*
* GFP_NOWAIT and GFP_ATOMIC are not supported, neither is the __GFP_NORETRY modifier.
* __GFP_RETRY_MAYFAIL is supported, and it should be used only if kmalloc is
* preferable to the vmalloc fallback, due to visible performance drawbacks.
*
* Return: pointer to the allocated memory of %NULL in case of failure
*/
void *__kvmalloc_node_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, int node)
{
gfp_t kmalloc_flags = flags;
void *ret;
/*
* We want to attempt a large physically contiguous block first because
* it is less likely to fragment multiple larger blocks and therefore
* contribute to a long term fragmentation less than vmalloc fallback.
* However make sure that larger requests are not too disruptive - no
* OOM killer and no allocation failure warnings as we have a fallback.
*/
if (size > PAGE_SIZE) {
kmalloc_flags |= __GFP_NOWARN;
if (!(kmalloc_flags & __GFP_RETRY_MAYFAIL))
kmalloc_flags |= __GFP_NORETRY;
/* nofail semantic is implemented by the vmalloc fallback */
kmalloc_flags &= ~__GFP_NOFAIL;
}
ret = __kmalloc_node_noprof(PASS_BUCKET_PARAMS(size, b), kmalloc_flags, node);
/*
* It doesn't really make sense to fallback to vmalloc for sub page
* requests
*/
if (ret || size <= PAGE_SIZE)
return ret;
/* non-sleeping allocations are not supported by vmalloc */
if (!gfpflags_allow_blocking(flags))
return NULL;
/* Don't even allow crazy sizes */
if (unlikely(size > INT_MAX)) {
WARN_ON_ONCE(!(flags & __GFP_NOWARN));
return NULL;
}
/*
* kvmalloc() can always use VM_ALLOW_HUGE_VMAP,
* since the callers already cannot assume anything
* about the resulting pointer, and cannot play
* protection games.
*/
return __vmalloc_node_range_noprof(size, 1, VMALLOC_START, VMALLOC_END,
flags, PAGE_KERNEL, VM_ALLOW_HUGE_VMAP,
node, __builtin_return_address(0));
}
EXPORT_SYMBOL(__kvmalloc_node_noprof);
/**
* kvfree() - Free memory.
* @addr: Pointer to allocated memory.
*
* kvfree frees memory allocated by any of vmalloc(), kmalloc() or kvmalloc().
* It is slightly more efficient to use kfree() or vfree() if you are certain
* that you know which one to use.
*
* Context: Either preemptible task context or not-NMI interrupt.
*/
void kvfree(const void *addr)
{
if (is_vmalloc_addr(addr))
vfree(addr);
else
kfree(addr);
}
EXPORT_SYMBOL(kvfree);
/**
* kvfree_sensitive - Free a data object containing sensitive information.
* @addr: address of the data object to be freed.
* @len: length of the data object.
*
* Use the special memzero_explicit() function to clear the content of a
* kvmalloc'ed object containing sensitive data to make sure that the
* compiler won't optimize out the data clearing.
*/
void kvfree_sensitive(const void *addr, size_t len)
{
if (likely(!ZERO_OR_NULL_PTR(addr))) {
memzero_explicit((void *)addr, len);
kvfree(addr);
}
}
EXPORT_SYMBOL(kvfree_sensitive);
void *kvrealloc_noprof(const void *p, size_t oldsize, size_t newsize, gfp_t flags)
{
void *newp;
if (oldsize >= newsize)
return (void *)p;
newp = kvmalloc_noprof(newsize, flags);
if (!newp)
return NULL;
memcpy(newp, p, oldsize);
kvfree(p);
return newp;
}
EXPORT_SYMBOL(kvrealloc_noprof);
/**
* __vmalloc_array - allocate memory for a virtually contiguous array.
* @n: number of elements.
* @size: element size.
* @flags: the type of memory to allocate (see kmalloc).
*/
void *__vmalloc_array_noprof(size_t n, size_t size, gfp_t flags)
{
size_t bytes;
if (unlikely(check_mul_overflow(n, size, &bytes)))
return NULL;
return __vmalloc_noprof(bytes, flags);
}
EXPORT_SYMBOL(__vmalloc_array_noprof);
/**
* vmalloc_array - allocate memory for a virtually contiguous array.
* @n: number of elements.
* @size: element size.
*/
void *vmalloc_array_noprof(size_t n, size_t size)
{
return __vmalloc_array_noprof(n, size, GFP_KERNEL);
}
EXPORT_SYMBOL(vmalloc_array_noprof);
/**
* __vcalloc - allocate and zero memory for a virtually contiguous array.
* @n: number of elements.
* @size: element size.
* @flags: the type of memory to allocate (see kmalloc).
*/
void *__vcalloc_noprof(size_t n, size_t size, gfp_t flags)
{
return __vmalloc_array_noprof(n, size, flags | __GFP_ZERO);
}
EXPORT_SYMBOL(__vcalloc_noprof);
/**
* vcalloc - allocate and zero memory for a virtually contiguous array.
* @n: number of elements.
* @size: element size.
*/
void *vcalloc_noprof(size_t n, size_t size)
{
return __vmalloc_array_noprof(n, size, GFP_KERNEL | __GFP_ZERO);
}
EXPORT_SYMBOL(vcalloc_noprof);
struct anon_vma *folio_anon_vma(struct folio *folio)
{
unsigned long mapping = (unsigned long)folio->mapping;
if ((mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON)
return NULL;
return (void *)(mapping - PAGE_MAPPING_ANON);
}
/**
* folio_mapping - Find the mapping where this folio is stored.
* @folio: The folio.
*
* For folios which are in the page cache, return the mapping that this
* page belongs to. Folios in the swap cache return the swap mapping
* this page is stored in (which is different from the mapping for the
* swap file or swap device where the data is stored).
*
* You can call this for folios which aren't in the swap cache or page
* cache and it will return NULL.
*/
struct address_space *folio_mapping(struct folio *folio)
{
struct address_space *mapping;
/* This happens if someone calls flush_dcache_page on slab page */
if (unlikely(folio_test_slab(folio)))
return NULL;
if (unlikely(folio_test_swapcache(folio)))
return swap_address_space(folio->swap);
mapping = folio->mapping;
if ((unsigned long)mapping & PAGE_MAPPING_FLAGS)
return NULL;
return mapping;
}
EXPORT_SYMBOL(folio_mapping);
/**
* folio_copy - Copy the contents of one folio to another.
* @dst: Folio to copy to.
* @src: Folio to copy from.
*
* The bytes in the folio represented by @src are copied to @dst.
* Assumes the caller has validated that @dst is at least as large as @src.
* Can be called in atomic context for order-0 folios, but if the folio is
* larger, it may sleep.
*/
void folio_copy(struct folio *dst, struct folio *src)
{
long i = 0;
long nr = folio_nr_pages(src);
for (;;) {
copy_highpage(folio_page(dst, i), folio_page(src, i));
if (++i == nr)
break;
cond_resched();
}
}
EXPORT_SYMBOL(folio_copy);
int folio_mc_copy(struct folio *dst, struct folio *src)
{
long nr = folio_nr_pages(src);
long i = 0;
for (;;) {
if (copy_mc_highpage(folio_page(dst, i), folio_page(src, i)))
return -EHWPOISON;
if (++i == nr)
break;
cond_resched();
}
return 0;
}
EXPORT_SYMBOL(folio_mc_copy);
int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS;
int sysctl_overcommit_ratio __read_mostly = 50;
unsigned long sysctl_overcommit_kbytes __read_mostly;
int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */
unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */
int overcommit_ratio_handler(const struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos)
{
int ret;
ret = proc_dointvec(table, write, buffer, lenp, ppos);
if (ret == 0 && write)
sysctl_overcommit_kbytes = 0;
return ret;
}
static void sync_overcommit_as(struct work_struct *dummy)
{
percpu_counter_sync(&vm_committed_as);
}
int overcommit_policy_handler(const struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos)
{
struct ctl_table t;
int new_policy = -1;
int ret;
/*
* The deviation of sync_overcommit_as could be big with loose policy
* like OVERCOMMIT_ALWAYS/OVERCOMMIT_GUESS. When changing policy to
* strict OVERCOMMIT_NEVER, we need to reduce the deviation to comply
* with the strict "NEVER", and to avoid possible race condition (even
* though user usually won't too frequently do the switching to policy
* OVERCOMMIT_NEVER), the switch is done in the following order:
* 1. changing the batch
* 2. sync percpu count on each CPU
* 3. switch the policy
*/
if (write) {
t = *table;
t.data = &new_policy;
ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
if (ret || new_policy == -1)
return ret;
mm_compute_batch(new_policy);
if (new_policy == OVERCOMMIT_NEVER)
schedule_on_each_cpu(sync_overcommit_as);
sysctl_overcommit_memory = new_policy;
} else {
ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
}
return ret;
}
int overcommit_kbytes_handler(const struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos)
{
int ret;
ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
if (ret == 0 && write)
sysctl_overcommit_ratio = 0;
return ret;
}
/*
* Committed memory limit enforced when OVERCOMMIT_NEVER policy is used
*/
unsigned long vm_commit_limit(void)
{
unsigned long allowed;
if (sysctl_overcommit_kbytes)
allowed = sysctl_overcommit_kbytes >> (PAGE_SHIFT - 10);
else
allowed = ((totalram_pages() - hugetlb_total_pages())
* sysctl_overcommit_ratio / 100);
allowed += total_swap_pages;
return allowed;
}
/*
* Make sure vm_committed_as in one cacheline and not cacheline shared with
* other variables. It can be updated by several CPUs frequently.
*/
struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp;
/*
* The global memory commitment made in the system can be a metric
* that can be used to drive ballooning decisions when Linux is hosted
* as a guest. On Hyper-V, the host implements a policy engine for dynamically
* balancing memory across competing virtual machines that are hosted.
* Several metrics drive this policy engine including the guest reported
* memory commitment.
*
* The time cost of this is very low for small platforms, and for big
* platform like a 2S/36C/72T Skylake server, in worst case where
* vm_committed_as's spinlock is under severe contention, the time cost
* could be about 30~40 microseconds.
*/
unsigned long vm_memory_committed(void)
{
return percpu_counter_sum_positive(&vm_committed_as);
}
EXPORT_SYMBOL_GPL(vm_memory_committed);
/*
* Check that a process has enough memory to allocate a new virtual
* mapping. 0 means there is enough memory for the allocation to
* succeed and -ENOMEM implies there is not.
*
* We currently support three overcommit policies, which are set via the
* vm.overcommit_memory sysctl. See Documentation/mm/overcommit-accounting.rst
*
* Strict overcommit modes added 2002 Feb 26 by Alan Cox.
* Additional code 2002 Jul 20 by Robert Love.
*
* cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
*
* Note this is a helper function intended to be used by LSMs which
* wish to use this logic.
*/
int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
{
long allowed;
unsigned long bytes_failed;
vm_acct_memory(pages);
/*
* Sometimes we want to use more memory than we have
*/
if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
return 0;
if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
if (pages > totalram_pages() + total_swap_pages)
goto error;
return 0;
}
allowed = vm_commit_limit();
/*
* Reserve some for root
*/
if (!cap_sys_admin)
allowed -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
/*
* Don't let a single process grow so big a user can't recover
*/
if (mm) {
long reserve = sysctl_user_reserve_kbytes >> (PAGE_SHIFT - 10);
allowed -= min_t(long, mm->total_vm / 32, reserve);
}
if (percpu_counter_read_positive(&vm_committed_as) < allowed)
return 0;
error:
bytes_failed = pages << PAGE_SHIFT;
pr_warn_ratelimited("%s: pid: %d, comm: %s, bytes: %lu not enough memory for the allocation\n",
__func__, current->pid, current->comm, bytes_failed);
vm_unacct_memory(pages);
return -ENOMEM;
}
/**
* get_cmdline() - copy the cmdline value to a buffer.
* @task: the task whose cmdline value to copy.
* @buffer: the buffer to copy to.
* @buflen: the length of the buffer. Larger cmdline values are truncated
* to this length.
*
* Return: the size of the cmdline field copied. Note that the copy does
* not guarantee an ending NULL byte.
*/
int get_cmdline(struct task_struct *task, char *buffer, int buflen)
{
int res = 0;
unsigned int len;
struct mm_struct *mm = get_task_mm(task);
unsigned long arg_start, arg_end, env_start, env_end;
if (!mm)
goto out;
if (!mm->arg_end)
goto out_mm; /* Shh! No looking before we're done */
spin_lock(&mm->arg_lock);
arg_start = mm->arg_start;
arg_end = mm->arg_end;
env_start = mm->env_start;
env_end = mm->env_end;
spin_unlock(&mm->arg_lock);
len = arg_end - arg_start;
if (len > buflen)
len = buflen;
res = access_process_vm(task, arg_start, buffer, len, FOLL_FORCE);
/*
* If the nul at the end of args has been overwritten, then
* assume application is using setproctitle(3).
*/
if (res > 0 && buffer[res-1] != '\0' && len < buflen) {
len = strnlen(buffer, res);
if (len < res) {
res = len;
} else {
len = env_end - env_start;
if (len > buflen - res)
len = buflen - res;
res += access_process_vm(task, env_start,
buffer+res, len,
FOLL_FORCE);
res = strnlen(buffer, res);
}
}
out_mm:
mmput(mm);
out:
return res;
}
int __weak memcmp_pages(struct page *page1, struct page *page2)
{
char *addr1, *addr2;
int ret;
addr1 = kmap_local_page(page1);
addr2 = kmap_local_page(page2);
ret = memcmp(addr1, addr2, PAGE_SIZE);
kunmap_local(addr2);
kunmap_local(addr1);
return ret;
}
#ifdef CONFIG_PRINTK
/**
* mem_dump_obj - Print available provenance information
* @object: object for which to find provenance information.
*
* This function uses pr_cont(), so that the caller is expected to have
* printed out whatever preamble is appropriate. The provenance information
* depends on the type of object and on how much debugging is enabled.
* For example, for a slab-cache object, the slab name is printed, and,
* if available, the return address and stack trace from the allocation
* and last free path of that object.
*/
void mem_dump_obj(void *object)
{
const char *type;
if (kmem_dump_obj(object))
return;
if (vmalloc_dump_obj(object))
return;
if (is_vmalloc_addr(object))
type = "vmalloc memory";
else if (virt_addr_valid(object))
type = "non-slab/vmalloc memory";
else if (object == NULL)
type = "NULL pointer";
else if (object == ZERO_SIZE_PTR)
type = "zero-size pointer";
else
type = "non-paged memory";
pr_cont(" %s\n", type);
}
EXPORT_SYMBOL_GPL(mem_dump_obj);
#endif
/*
* A driver might set a page logically offline -- PageOffline() -- and
* turn the page inaccessible in the hypervisor; after that, access to page
* content can be fatal.
*
* Some special PFN walkers -- i.e., /proc/kcore -- read content of random
* pages after checking PageOffline(); however, these PFN walkers can race
* with drivers that set PageOffline().
*
* page_offline_freeze()/page_offline_thaw() allows for a subsystem to
* synchronize with such drivers, achieving that a page cannot be set
* PageOffline() while frozen.
*
* page_offline_begin()/page_offline_end() is used by drivers that care about
* such races when setting a page PageOffline().
*/
static DECLARE_RWSEM(page_offline_rwsem);
void page_offline_freeze(void)
{
down_read(&page_offline_rwsem);
}
void page_offline_thaw(void)
{
up_read(&page_offline_rwsem);
}
void page_offline_begin(void)
{
down_write(&page_offline_rwsem);
}
EXPORT_SYMBOL(page_offline_begin);
void page_offline_end(void)
{
up_write(&page_offline_rwsem);
}
EXPORT_SYMBOL(page_offline_end);
#ifndef flush_dcache_folio
void flush_dcache_folio(struct folio *folio)
{
long i, nr = folio_nr_pages(folio);
for (i = 0; i < nr; i++)
flush_dcache_page(folio_page(folio, i));
}
EXPORT_SYMBOL(flush_dcache_folio);
#endif