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mm: start tracking VMAs with maple tree

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Start tracking the VMAs with the new maple tree structure in parallel with
the rb_tree.  Add debug and trace events for maple tree operations and
duplicate the rb_tree that is created on forks into the maple tree.

The maple tree is added to the mm_struct including the mm_init struct,
added support in required mm/mmap functions, added tracking in kernel/fork
for process forking, and used to find the unmapped_area and checked
against what the rbtree finds.

This also moves the mmap_lock() in exit_mmap() since the oom reaper call
does walk the VMAs.  Otherwise lockdep will be unhappy if oom happens.

When splitting a vma fails due to allocations of the maple tree nodes,
the error path in __split_vma() calls new->vm_ops->close(new).  The page
accounting for hugetlb is actually in the close() operation,  so it
accounts for the removal of 1/2 of the VMA which was not adjusted.  This
results in a negative exit value.  To avoid the negative charge, set
vm_start = vm_end and vm_pgoff = 0.

There is also a potential accounting issue in special mappings from
insert_vm_struct() failing to allocate, so reverse the charge there in
the failure scenario.

Link: https://lkml.kernel.org/r/20220906194824.2110408-9-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Liam R. Howlett 2022-09-06 19:48:45 +00:00 committed by Andrew Morton
parent e15e06a839
commit d4af56c5c7
9 changed files with 437 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/x86/kernel/tboot.c
View File

@ -96,6 +96,7 @@ void __init tboot_probe(void)
static pgd_t *tboot_pg_dir;
static struct mm_struct tboot_mm = {
.mm_rb = RB_ROOT,
.mm_mt = MTREE_INIT_EXT(mm_mt, MM_MT_FLAGS, tboot_mm.mmap_lock),
.pgd = swapper_pg_dir,
.mm_users = ATOMIC_INIT(2),
.mm_count = ATOMIC_INIT(1),

1
drivers/firmware/efi/efi.c
View File

@ -58,6 +58,7 @@ static unsigned long __initdata rt_prop = EFI_INVALID_TABLE_ADDR;
struct mm_struct efi_mm = {
.mm_rb = RB_ROOT,
.mm_mt = MTREE_INIT_EXT(mm_mt, MM_MT_FLAGS, efi_mm.mmap_lock),
.mm_users = ATOMIC_INIT(2),
.mm_count = ATOMIC_INIT(1),
.write_protect_seq = SEQCNT_ZERO(efi_mm.write_protect_seq),

5
include/linux/mm.h
View File

@ -2567,6 +2567,8 @@ extern bool arch_has_descending_max_zone_pfns(void);
/* nommu.c */
extern atomic_long_t mmap_pages_allocated;
extern int nommu_shrink_inode_mappings(struct inode *, size_t, size_t);
/* mmap.c */
void vma_mas_store(struct vm_area_struct *vma, struct ma_state *mas);
/* interval_tree.c */
void vma_interval_tree_insert(struct vm_area_struct *node,
@ -2630,6 +2632,9 @@ extern struct vm_area_struct *copy_vma(struct vm_area_struct **,
bool *need_rmap_locks);
extern void exit_mmap(struct mm_struct *);
void vma_mas_store(struct vm_area_struct *vma, struct ma_state *mas);
void vma_mas_remove(struct vm_area_struct *vma, struct ma_state *mas);
static inline int check_data_rlimit(unsigned long rlim,
unsigned long new,
unsigned long start,

3
include/linux/mm_types.h
View File

@ -9,6 +9,7 @@
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/rbtree.h>
#include <linux/maple_tree.h>
#include <linux/rwsem.h>
#include <linux/completion.h>
#include <linux/cpumask.h>
@ -486,6 +487,7 @@ struct kioctx_table;
struct mm_struct {
struct {
struct vm_area_struct *mmap; /* list of VMAs */
struct maple_tree mm_mt;
struct rb_root mm_rb;
u64 vmacache_seqnum; /* per-thread vmacache */
#ifdef CONFIG_MMU
@ -697,6 +699,7 @@ struct mm_struct {
unsigned long cpu_bitmap[];
};
#define MM_MT_FLAGS (MT_FLAGS_ALLOC_RANGE | MT_FLAGS_LOCK_EXTERN)
extern struct mm_struct init_mm;
/* Pointer magic because the dynamic array size confuses some compilers. */

73
include/trace/events/mmap.h
View File

@ -42,6 +42,79 @@ TRACE_EVENT(vm_unmapped_area,
__entry->low_limit, __entry->high_limit, __entry->align_mask,
__entry->align_offset)
);
TRACE_EVENT(vma_mas_szero,
TP_PROTO(struct maple_tree *mt, unsigned long start,
unsigned long end),
TP_ARGS(mt, start, end),
TP_STRUCT__entry(
__field(struct maple_tree *, mt)
__field(unsigned long, start)
__field(unsigned long, end)
),
TP_fast_assign(
__entry->mt = mt;
__entry->start = start;
__entry->end = end;
),
TP_printk("mt_mod %p, (NULL), SNULL, %lu, %lu,",
__entry->mt,
(unsigned long) __entry->start,
(unsigned long) __entry->end
)
);
TRACE_EVENT(vma_store,
TP_PROTO(struct maple_tree *mt, struct vm_area_struct *vma),
TP_ARGS(mt, vma),
TP_STRUCT__entry(
__field(struct maple_tree *, mt)
__field(struct vm_area_struct *, vma)
__field(unsigned long, vm_start)
__field(unsigned long, vm_end)
),
TP_fast_assign(
__entry->mt = mt;
__entry->vma = vma;
__entry->vm_start = vma->vm_start;
__entry->vm_end = vma->vm_end - 1;
),
TP_printk("mt_mod %p, (%p), STORE, %lu, %lu,",
__entry->mt, __entry->vma,
(unsigned long) __entry->vm_start,
(unsigned long) __entry->vm_end
)
);
TRACE_EVENT(exit_mmap,
TP_PROTO(struct mm_struct *mm),
TP_ARGS(mm),
TP_STRUCT__entry(
__field(struct mm_struct *, mm)
__field(struct maple_tree *, mt)
),
TP_fast_assign(
__entry->mm = mm;
__entry->mt = &mm->mm_mt;
),
TP_printk("mt_mod %p, DESTROY\n",
__entry->mt
)
);
#endif
/* This part must be outside protection */

20
kernel/fork.c
View File

@ -585,6 +585,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
int retval;
unsigned long charge;
LIST_HEAD(uf);
MA_STATE(mas, &mm->mm_mt, 0, 0);
uprobe_start_dup_mmap();
if (mmap_write_lock_killable(oldmm)) {
@ -614,6 +615,10 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
goto out;
khugepaged_fork(mm, oldmm);
retval = mas_expected_entries(&mas, oldmm->map_count);
if (retval)
goto out;
prev = NULL;
for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) {
struct file *file;
@ -629,7 +634,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
*/
if (fatal_signal_pending(current)) {
retval = -EINTR;
goto out;
goto loop_out;
}
if (mpnt->vm_flags & VM_ACCOUNT) {
unsigned long len = vma_pages(mpnt);
@ -694,6 +699,11 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
rb_link = &tmp->vm_rb.rb_right;
rb_parent = &tmp->vm_rb;
/* Link the vma into the MT */
mas.index = tmp->vm_start;
mas.last = tmp->vm_end - 1;
mas_store(&mas, tmp);
mm->map_count++;
if (!(tmp->vm_flags & VM_WIPEONFORK))
retval = copy_page_range(tmp, mpnt);
@ -702,10 +712,12 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
tmp->vm_ops->open(tmp);
if (retval)
goto out;
goto loop_out;
}
/* a new mm has just been created */
retval = arch_dup_mmap(oldmm, mm);
loop_out:
mas_destroy(&mas);
out:
mmap_write_unlock(mm);
flush_tlb_mm(oldmm);
@ -721,7 +733,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
fail_nomem:
retval = -ENOMEM;
vm_unacct_memory(charge);
goto out;
goto loop_out;
}
static inline int mm_alloc_pgd(struct mm_struct *mm)
@ -1111,6 +1123,8 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
{
mm->mmap = NULL;
mm->mm_rb = RB_ROOT;
mt_init_flags(&mm->mm_mt, MM_MT_FLAGS);
mt_set_external_lock(&mm->mm_mt, &mm->mmap_lock);
mm->vmacache_seqnum = 0;
atomic_set(&mm->mm_users, 1);
atomic_set(&mm->mm_count, 1);

2
mm/init-mm.c
View File

@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/mm_types.h>
#include <linux/rbtree.h>
#include <linux/maple_tree.h>
#include <linux/rwsem.h>
#include <linux/spinlock.h>
#include <linux/list.h>
@ -29,6 +30,7 @@
*/
struct mm_struct init_mm = {
.mm_rb = RB_ROOT,
.mm_mt = MTREE_INIT_EXT(mm_mt, MM_MT_FLAGS, init_mm.mmap_lock),
.pgd = swapper_pg_dir,
.mm_users = ATOMIC_INIT(2),
.mm_count = ATOMIC_INIT(1),

357
mm/mmap.c
View File

@ -334,7 +334,71 @@ static int browse_rb(struct mm_struct *mm)
}
return bug ? -1 : i;
}
#if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
extern void mt_validate(struct maple_tree *mt);
extern void mt_dump(const struct maple_tree *mt);
/* Validate the maple tree */
static void validate_mm_mt(struct mm_struct *mm)
{
struct maple_tree *mt = &mm->mm_mt;
struct vm_area_struct *vma_mt, *vma = mm->mmap;
MA_STATE(mas, mt, 0, 0);
mt_validate(&mm->mm_mt);
mas_for_each(&mas, vma_mt, ULONG_MAX) {
if (xa_is_zero(vma_mt))
continue;
if (!vma)
break;
if ((vma != vma_mt) ||
(vma->vm_start != vma_mt->vm_start) ||
(vma->vm_end != vma_mt->vm_end) ||
(vma->vm_start != mas.index) ||
(vma->vm_end - 1 != mas.last)) {
pr_emerg("issue in %s\n", current->comm);
dump_stack();
#ifdef CONFIG_DEBUG_VM
dump_vma(vma_mt);
pr_emerg("and next in rb\n");
dump_vma(vma->vm_next);
#endif
pr_emerg("mt piv: %p %lu - %lu\n", vma_mt,
mas.index, mas.last);
pr_emerg("mt vma: %p %lu - %lu\n", vma_mt,
vma_mt->vm_start, vma_mt->vm_end);
pr_emerg("rb vma: %p %lu - %lu\n", vma,
vma->vm_start, vma->vm_end);
pr_emerg("rb->next = %p %lu - %lu\n", vma->vm_next,
vma->vm_next->vm_start, vma->vm_next->vm_end);
mt_dump(mas.tree);
if (vma_mt->vm_end != mas.last + 1) {
pr_err("vma: %p vma_mt %lu-%lu\tmt %lu-%lu\n",
mm, vma_mt->vm_start, vma_mt->vm_end,
mas.index, mas.last);
mt_dump(mas.tree);
}
VM_BUG_ON_MM(vma_mt->vm_end != mas.last + 1, mm);
if (vma_mt->vm_start != mas.index) {
pr_err("vma: %p vma_mt %p %lu - %lu doesn't match\n",
mm, vma_mt, vma_mt->vm_start, vma_mt->vm_end);
mt_dump(mas.tree);
}
VM_BUG_ON_MM(vma_mt->vm_start != mas.index, mm);
}
VM_BUG_ON(vma != vma_mt);
vma = vma->vm_next;
}
VM_BUG_ON(vma);
}
#else
#define validate_mm_mt(root) do { } while (0)
#endif
static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore)
{
struct rb_node *nd;
@ -389,6 +453,7 @@ static void validate_mm(struct mm_struct *mm)
}
#else
#define validate_mm_rb(root, ignore) do { } while (0)
#define validate_mm_mt(root) do { } while (0)
#define validate_mm(mm) do { } while (0)
#endif
@ -633,6 +698,56 @@ static void __vma_link_file(struct vm_area_struct *vma)
}
}
/*
* vma_mas_store() - Store a VMA in the maple tree.
* @vma: The vm_area_struct
* @mas: The maple state
*
* Efficient way to store a VMA in the maple tree when the @mas has already
* walked to the correct location.
*
* Note: the end address is inclusive in the maple tree.
*/
void vma_mas_store(struct vm_area_struct *vma, struct ma_state *mas)
{
trace_vma_store(mas->tree, vma);
mas_set_range(mas, vma->vm_start, vma->vm_end - 1);
mas_store_prealloc(mas, vma);
}
/*
* vma_mas_remove() - Remove a VMA from the maple tree.
* @vma: The vm_area_struct
* @mas: The maple state
*
* Efficient way to remove a VMA from the maple tree when the @mas has already
* been established and points to the correct location.
* Note: the end address is inclusive in the maple tree.
*/
void vma_mas_remove(struct vm_area_struct *vma, struct ma_state *mas)
{
trace_vma_mas_szero(mas->tree, vma->vm_start, vma->vm_end - 1);
mas->index = vma->vm_start;
mas->last = vma->vm_end - 1;
mas_store_prealloc(mas, NULL);
}
/*
* vma_mas_szero() - Set a given range to zero. Used when modifying a
* vm_area_struct start or end.
*
* @mm: The struct_mm
* @start: The start address to zero
* @end: The end address to zero.
*/
static inline void vma_mas_szero(struct ma_state *mas, unsigned long start,
unsigned long end)
{
trace_vma_mas_szero(mas->tree, start, end - 1);
mas_set_range(mas, start, end - 1);
mas_store_prealloc(mas, NULL);
}
static void
__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
struct vm_area_struct *prev, struct rb_node **rb_link,
@ -642,17 +757,22 @@ __vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
__vma_link_rb(mm, vma, rb_link, rb_parent);
}
static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
struct vm_area_struct *prev, struct rb_node **rb_link,
struct rb_node *rb_parent)
{
MA_STATE(mas, &mm->mm_mt, 0, 0);
struct address_space *mapping = NULL;
if (mas_preallocate(&mas, vma, GFP_KERNEL))
return -ENOMEM;
if (vma->vm_file) {
mapping = vma->vm_file->f_mapping;
i_mmap_lock_write(mapping);
}
vma_mas_store(vma, &mas);
__vma_link(mm, vma, prev, rb_link, rb_parent);
__vma_link_file(vma);
@ -661,13 +781,15 @@ static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
mm->map_count++;
validate_mm(mm);
return 0;
}
/*
* Helper for vma_adjust() in the split_vma insert case: insert a vma into the
* mm's list and rbtree. It has already been inserted into the interval tree.
*/
static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
static void __insert_vm_struct(struct mm_struct *mm, struct ma_state *mas,
struct vm_area_struct *vma)
{
struct vm_area_struct *prev;
struct rb_node **rb_link, *rb_parent;
@ -675,7 +797,10 @@ static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
if (find_vma_links(mm, vma->vm_start, vma->vm_end,
&prev, &rb_link, &rb_parent))
BUG();
__vma_link(mm, vma, prev, rb_link, rb_parent);
vma_mas_store(vma, mas);
__vma_link_list(mm, vma, prev);
__vma_link_rb(mm, vma, rb_link, rb_parent);
mm->map_count++;
}
@ -702,6 +827,7 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
{
struct mm_struct *mm = vma->vm_mm;
struct vm_area_struct *next = vma->vm_next, *orig_vma = vma;
struct vm_area_struct *next_next;
struct address_space *mapping = NULL;
struct rb_root_cached *root = NULL;
struct anon_vma *anon_vma = NULL;
@ -709,10 +835,13 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
bool start_changed = false, end_changed = false;
long adjust_next = 0;
int remove_next = 0;
MA_STATE(mas, &mm->mm_mt, 0, 0);
struct vm_area_struct *exporter = NULL, *importer = NULL;
validate_mm(mm);
validate_mm_mt(mm);
if (next && !insert) {
struct vm_area_struct *exporter = NULL, *importer = NULL;
if (end >= next->vm_end) {
/*
* vma expands, overlapping all the next, and
@ -741,10 +870,11 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
* remove_next == 1 is case 1 or 7.
*/
remove_next = 1 + (end > next->vm_end);
if (remove_next == 2)
next_next = find_vma(mm, next->vm_end);
VM_WARN_ON(remove_next == 2 &&
end != next->vm_next->vm_end);
/* trim end to next, for case 6 first pass */
end = next->vm_end;
}
exporter = next;
@ -792,9 +922,11 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
return error;
}
}
again:
vma_adjust_trans_huge(orig_vma, start, end, adjust_next);
if (mas_preallocate(&mas, vma, GFP_KERNEL))
return -ENOMEM;
vma_adjust_trans_huge(orig_vma, start, end, adjust_next);
if (file) {
mapping = file->f_mapping;
root = &mapping->i_mmap;
@ -835,17 +967,28 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
}
if (start != vma->vm_start) {
unsigned long old_start = vma->vm_start;
vma->vm_start = start;
if (old_start < start)
vma_mas_szero(&mas, old_start, start);
start_changed = true;
}
if (end != vma->vm_end) {
unsigned long old_end = vma->vm_end;
vma->vm_end = end;
if (old_end > end)
vma_mas_szero(&mas, end, old_end);
end_changed = true;
}
if (end_changed || start_changed)
vma_mas_store(vma, &mas);
vma->vm_pgoff = pgoff;
if (adjust_next) {
next->vm_start += adjust_next;
next->vm_pgoff += adjust_next >> PAGE_SHIFT;
vma_mas_store(next, &mas);
}
if (file) {
@ -859,10 +1002,14 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
/*
* vma_merge has merged next into vma, and needs
* us to remove next before dropping the locks.
* Since we have expanded over this vma, the maple tree will
* have overwritten by storing the value
*/
if (remove_next != 3)
if (remove_next != 3) {
__vma_unlink(mm, next, next);
else
if (remove_next == 2)
__vma_unlink(mm, next_next, next_next);
} else {
/*
* vma is not before next if they've been
* swapped.
@ -873,15 +1020,19 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
* "vma").
*/
__vma_unlink(mm, next, vma);
if (file)
}
if (file) {
__remove_shared_vm_struct(next, file, mapping);
if (remove_next == 2)
__remove_shared_vm_struct(next_next, file, mapping);
}
} else if (insert) {
/*
* split_vma has split insert from vma, and needs
* us to insert it before dropping the locks
* (it may either follow vma or precede it).
*/
__insert_vm_struct(mm, insert);
__insert_vm_struct(mm, &mas, insert);
} else {
if (start_changed)
vma_gap_update(vma);
@ -909,6 +1060,7 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
}
if (remove_next) {
again:
if (file) {
uprobe_munmap(next, next->vm_start, next->vm_end);
fput(file);
@ -930,7 +1082,7 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
* "next->vm_prev->vm_end" changed and the
* "vma->vm_next" gap must be updated.
*/
next = vma->vm_next;
next = next_next;
} else {
/*
* For the scope of the comment "next" and
@ -946,7 +1098,6 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
}
if (remove_next == 2) {
remove_next = 1;
end = next->vm_end;
goto again;
}
else if (next)
@ -978,6 +1129,7 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
uprobe_mmap(insert);
validate_mm(mm);
validate_mm_mt(mm);
return 0;
}
@ -1131,6 +1283,7 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
struct vm_area_struct *area, *next;
int err;
validate_mm_mt(mm);
/*
* We later require that vma->vm_flags == vm_flags,
* so this tests vma->vm_flags & VM_SPECIAL, too.
@ -1206,6 +1359,7 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
khugepaged_enter_vma(area, vm_flags);
return area;
}
validate_mm_mt(mm);
return NULL;
}
@ -1688,6 +1842,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
struct rb_node **rb_link, *rb_parent;
unsigned long charged = 0;
validate_mm_mt(mm);
/* Check against address space limit. */
if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) {
unsigned long nr_pages;
@ -1802,7 +1957,13 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
goto free_vma;
}
vma_link(mm, vma, prev, rb_link, rb_parent);
if (vma_link(mm, vma, prev, rb_link, rb_parent)) {
error = -ENOMEM;
if (file)
goto unmap_and_free_vma;
else
goto free_vma;
}
/*
* vma_merge() calls khugepaged_enter_vma() either, the below
@ -1842,6 +2003,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
vma_set_page_prot(vma);
validate_mm_mt(mm);
return addr;
unmap_and_free_vma:
@ -1857,6 +2019,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
unacct_error:
if (charged)
vm_unacct_memory(charged);
validate_mm_mt(mm);
return error;
}
@ -1873,12 +2036,19 @@ static unsigned long unmapped_area(struct vm_unmapped_area_info *info)
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long length, low_limit, high_limit, gap_start, gap_end;
unsigned long gap;
MA_STATE(mas, &mm->mm_mt, 0, 0);
/* Adjust search length to account for worst case alignment overhead */
length = info->length + info->align_mask;
if (length < info->length)
return -ENOMEM;
mas_empty_area(&mas, info->low_limit, info->high_limit - 1,
length);
gap = mas.index;
gap += (info->align_offset - gap) & info->align_mask;
/* Adjust search limits by the desired length */
if (info->high_limit < length)
return -ENOMEM;
@ -1960,20 +2130,31 @@ static unsigned long unmapped_area(struct vm_unmapped_area_info *info)
VM_BUG_ON(gap_start + info->length > info->high_limit);
VM_BUG_ON(gap_start + info->length > gap_end);
VM_BUG_ON(gap != gap_start);
return gap_start;
}
static unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
struct vm_area_struct *vma = NULL;
unsigned long length, low_limit, high_limit, gap_start, gap_end;
unsigned long gap;
MA_STATE(mas, &mm->mm_mt, 0, 0);
validate_mm_mt(mm);
/* Adjust search length to account for worst case alignment overhead */
length = info->length + info->align_mask;
if (length < info->length)
return -ENOMEM;
mas_empty_area_rev(&mas, info->low_limit, info->high_limit - 1,
length);
gap = mas.last + 1 - info->length;
gap -= (gap - info->align_offset) & info->align_mask;
/*
* Adjust search limits by the desired length.
* See implementation comment at top of unmapped_area().
@ -2059,6 +2240,32 @@ static unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
VM_BUG_ON(gap_end < info->low_limit);
VM_BUG_ON(gap_end < gap_start);
if (gap != gap_end) {
pr_err("%s: %p Gap was found: mt %lu gap_end %lu\n", __func__,
mm, gap, gap_end);
pr_err("window was %lu - %lu size %lu\n", info->high_limit,
info->low_limit, length);
pr_err("mas.min %lu max %lu mas.last %lu\n", mas.min, mas.max,
mas.last);
pr_err("mas.index %lu align mask %lu offset %lu\n", mas.index,
info->align_mask, info->align_offset);
pr_err("rb_find_vma find on %lu => %p (%p)\n", mas.index,
find_vma(mm, mas.index), vma);
#if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
mt_dump(&mm->mm_mt);
#endif
{
struct vm_area_struct *dv = mm->mmap;
while (dv) {
pr_err("vma %p %lu-%lu\n", dv, dv->vm_start, dv->vm_end);
dv = dv->vm_next;
}
}
VM_BUG_ON(gap != gap_end);
}
return gap_end;
}
@ -2284,7 +2491,6 @@ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
vmacache_update(addr, vma);
return vma;
}
EXPORT_SYMBOL(find_vma);
/*
@ -2357,7 +2563,9 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
struct vm_area_struct *next;
unsigned long gap_addr;
int error = 0;
MA_STATE(mas, &mm->mm_mt, 0, 0);
validate_mm_mt(mm);
if (!(vma->vm_flags & VM_GROWSUP))
return -EFAULT;
@ -2381,10 +2589,15 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
/* Check that both stack segments have the same anon_vma? */
}
/* We must make sure the anon_vma is allocated. */
if (unlikely(anon_vma_prepare(vma)))
if (mas_preallocate(&mas, vma, GFP_KERNEL))
return -ENOMEM;
/* We must make sure the anon_vma is allocated. */
if (unlikely(anon_vma_prepare(vma))) {
mas_destroy(&mas);
return -ENOMEM;
}
/*
* vma->vm_start/vm_end cannot change under us because the caller
* is required to hold the mmap_lock in read mode. We need the
@ -2420,6 +2633,8 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
vm_stat_account(mm, vma->vm_flags, grow);
anon_vma_interval_tree_pre_update_vma(vma);
vma->vm_end = address;
/* Overwrite old entry in mtree. */
vma_mas_store(vma, &mas);
anon_vma_interval_tree_post_update_vma(vma);
if (vma->vm_next)
vma_gap_update(vma->vm_next);
@ -2434,6 +2649,8 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
anon_vma_unlock_write(vma->anon_vma);
khugepaged_enter_vma(vma, vma->vm_flags);
validate_mm(mm);
validate_mm_mt(mm);
mas_destroy(&mas);
return error;
}
#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
@ -2447,7 +2664,9 @@ int expand_downwards(struct vm_area_struct *vma,
struct mm_struct *mm = vma->vm_mm;
struct vm_area_struct *prev;
int error = 0;
MA_STATE(mas, &mm->mm_mt, 0, 0);
validate_mm(mm);
address &= PAGE_MASK;
if (address < mmap_min_addr)
return -EPERM;
@ -2461,10 +2680,15 @@ int expand_downwards(struct vm_area_struct *vma,
return -ENOMEM;
}
/* We must make sure the anon_vma is allocated. */
if (unlikely(anon_vma_prepare(vma)))
if (mas_preallocate(&mas, vma, GFP_KERNEL))
return -ENOMEM;
/* We must make sure the anon_vma is allocated. */
if (unlikely(anon_vma_prepare(vma))) {
mas_destroy(&mas);
return -ENOMEM;
}
/*
* vma->vm_start/vm_end cannot change under us because the caller
* is required to hold the mmap_lock in read mode. We need the
@ -2501,6 +2725,8 @@ int expand_downwards(struct vm_area_struct *vma,
anon_vma_interval_tree_pre_update_vma(vma);
vma->vm_start = address;
vma->vm_pgoff -= grow;
/* Overwrite old entry in mtree. */
vma_mas_store(vma, &mas);
anon_vma_interval_tree_post_update_vma(vma);
vma_gap_update(vma);
spin_unlock(&mm->page_table_lock);
@ -2512,6 +2738,7 @@ int expand_downwards(struct vm_area_struct *vma,
anon_vma_unlock_write(vma->anon_vma);
khugepaged_enter_vma(vma, vma->vm_flags);
validate_mm(mm);
mas_destroy(&mas);
return error;
}
@ -2633,14 +2860,17 @@ static void unmap_region(struct mm_struct *mm,
* vma list as we go..
*/
static bool
detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
struct vm_area_struct *prev, unsigned long end)
detach_vmas_to_be_unmapped(struct mm_struct *mm, struct ma_state *mas,
struct vm_area_struct *vma, struct vm_area_struct *prev,
unsigned long end)
{
struct vm_area_struct **insertion_point;
struct vm_area_struct *tail_vma = NULL;
insertion_point = (prev ? &prev->vm_next : &mm->mmap);
vma->vm_prev = NULL;
mas_set_range(mas, vma->vm_start, end - 1);
mas_store_prealloc(mas, NULL);
do {
vma_rb_erase(vma, &mm->mm_rb);
if (vma->vm_flags & VM_LOCKED)
@ -2681,6 +2911,7 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
{
struct vm_area_struct *new;
int err;
validate_mm_mt(mm);
if (vma->vm_ops && vma->vm_ops->may_split) {
err = vma->vm_ops->may_split(vma, addr);
@ -2723,6 +2954,9 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
if (!err)
return 0;
/* Avoid vm accounting in close() operation */
new->vm_start = new->vm_end;
new->vm_pgoff = 0;
/* Clean everything up if vma_adjust failed. */
if (new->vm_ops && new->vm_ops->close)
new->vm_ops->close(new);
@ -2733,6 +2967,7 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
mpol_put(vma_policy(new));
out_free_vma:
vm_area_free(new);
validate_mm_mt(mm);
return err;
}
@ -2759,6 +2994,8 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
{
unsigned long end;
struct vm_area_struct *vma, *prev, *last;
int error = -ENOMEM;
MA_STATE(mas, &mm->mm_mt, 0, 0);
if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start)
return -EINVAL;
@ -2779,6 +3016,9 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
vma = find_vma_intersection(mm, start, end);
if (!vma)
return 0;
if (mas_preallocate(&mas, vma, GFP_KERNEL))
return -ENOMEM;
prev = vma->vm_prev;
/*
@ -2789,7 +3029,6 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
* places tmp vma above, and higher split_vma places tmp vma below.
*/
if (start > vma->vm_start) {
int error;
/*
* Make sure that map_count on return from munmap() will
@ -2797,20 +3036,20 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
* its limit temporarily, to help free resources as expected.
*/
if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count)
return -ENOMEM;
goto map_count_exceeded;
error = __split_vma(mm, vma, start, 0);
if (error)
return error;
goto split_failed;
prev = vma;
}
/* Does it split the last one? */
last = find_vma(mm, end);
if (last && end > last->vm_start) {
int error = __split_vma(mm, last, end, 1);
error = __split_vma(mm, last, end, 1);
if (error)
return error;
goto split_failed;
}
vma = vma_next(mm, prev);
@ -2824,13 +3063,13 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
* split, despite we could. This is unlikely enough
* failure that it's not worth optimizing it for.
*/
int error = userfaultfd_unmap_prep(vma, start, end, uf);
error = userfaultfd_unmap_prep(vma, start, end, uf);
if (error)
return error;
goto userfaultfd_error;
}
/* Detach vmas from rbtree */
if (!detach_vmas_to_be_unmapped(mm, vma, prev, end))
if (!detach_vmas_to_be_unmapped(mm, &mas, vma, prev, end))
downgrade = false;
if (downgrade)
@ -2842,6 +3081,12 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
remove_vma_list(mm, vma);
return downgrade ? 1 : 0;
map_count_exceeded:
split_failed:
userfaultfd_error:
mas_destroy(&mas);
return error;
}
int do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
@ -2981,6 +3226,7 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla
pgoff_t pgoff = addr >> PAGE_SHIFT;
int error;
unsigned long mapped_addr;
validate_mm_mt(mm);
/* Until we need other flags, refuse anything except VM_EXEC. */
if ((flags & (~VM_EXEC)) != 0)
@ -3030,7 +3276,9 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla
vma->vm_pgoff = pgoff;
vma->vm_flags = flags;
vma->vm_page_prot = vm_get_page_prot(flags);
vma_link(mm, vma, prev, rb_link, rb_parent);
if (vma_link(mm, vma, prev, rb_link, rb_parent))
goto no_vma_link;
out:
perf_event_mmap(vma);
mm->total_vm += len >> PAGE_SHIFT;
@ -3038,7 +3286,12 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla
if (flags & VM_LOCKED)
mm->locked_vm += (len >> PAGE_SHIFT);
vma->vm_flags |= VM_SOFTDIRTY;
validate_mm_mt(mm);
return 0;
no_vma_link:
vm_area_free(vma);
return -ENOMEM;
}
int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags)
@ -3127,6 +3380,9 @@ void exit_mmap(struct mm_struct *mm)
vma = remove_vma(vma);
cond_resched();
}
trace_exit_mmap(mm);
__mt_destroy(&mm->mm_mt);
mm->mmap = NULL;
mmap_write_unlock(mm);
vm_unacct_memory(nr_accounted);
@ -3140,12 +3396,30 @@ int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
{
struct vm_area_struct *prev;
struct rb_node **rb_link, *rb_parent;
unsigned long start = vma->vm_start;
struct vm_area_struct *overlap = NULL;
unsigned long charged = vma_pages(vma);
if (find_vma_links(mm, vma->vm_start, vma->vm_end,
&prev, &rb_link, &rb_parent))
if (find_vma_intersection(mm, vma->vm_start, vma->vm_end))
return -ENOMEM;
overlap = mt_find(&mm->mm_mt, &start, vma->vm_end - 1);
if (overlap) {
pr_err("Found vma ending at %lu\n", start - 1);
pr_err("vma : %lu => %lu-%lu\n", (unsigned long)overlap,
overlap->vm_start, overlap->vm_end - 1);
#if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
mt_dump(&mm->mm_mt);
#endif
BUG();
}
if ((vma->vm_flags & VM_ACCOUNT) &&
security_vm_enough_memory_mm(mm, vma_pages(vma)))
security_vm_enough_memory_mm(mm, charged))
return -ENOMEM;
/*
@ -3165,7 +3439,11 @@ int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
}
vma_link(mm, vma, prev, rb_link, rb_parent);
if (vma_link(mm, vma, prev, rb_link, rb_parent)) {
vm_unacct_memory(charged);
return -ENOMEM;
}
return 0;
}
@ -3183,7 +3461,9 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
struct vm_area_struct *new_vma, *prev;
struct rb_node **rb_link, *rb_parent;
bool faulted_in_anon_vma = true;
unsigned long index = addr;
validate_mm_mt(mm);
/*
* If anonymous vma has not yet been faulted, update new pgoff
* to match new location, to increase its chance of merging.
@ -3195,6 +3475,8 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent))
return NULL; /* should never get here */
if (mt_find(&mm->mm_mt, &index, addr+len - 1))
BUG();
new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
vma->vm_userfaultfd_ctx, anon_vma_name(vma));
@ -3238,6 +3520,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
vma_link(mm, new_vma, prev, rb_link, rb_parent);
*need_rmap_locks = false;
}
validate_mm_mt(mm);
return new_vma;
out_free_mempol:
@ -3245,6 +3528,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
out_free_vma:
vm_area_free(new_vma);
out:
validate_mm_mt(mm);
return NULL;
}
@ -3381,6 +3665,7 @@ static struct vm_area_struct *__install_special_mapping(
int ret;
struct vm_area_struct *vma;
validate_mm_mt(mm);
vma = vm_area_alloc(mm);
if (unlikely(vma == NULL))
return ERR_PTR(-ENOMEM);
@ -3403,10 +3688,12 @@ static struct vm_area_struct *__install_special_mapping(
perf_event_mmap(vma);
validate_mm_mt(mm);
return vma;
out:
vm_area_free(vma);
validate_mm_mt(mm);
return ERR_PTR(ret);
}

13
mm/nommu.c
View File

@ -545,6 +545,19 @@ static void put_nommu_region(struct vm_region *region)
__put_nommu_region(region);
}
void vma_mas_store(struct vm_area_struct *vma, struct ma_state *mas)
{
mas_set_range(mas, vma->vm_start, vma->vm_end - 1);
mas_store_prealloc(mas, vma);
}
void vma_mas_remove(struct vm_area_struct *vma, struct ma_state *mas)
{
mas->index = vma->vm_start;
mas->last = vma->vm_end - 1;
mas_store_prealloc(mas, NULL);
}
/*
* add a VMA into a process's mm_struct in the appropriate place in the list
* and tree and add to the address space's page tree also if not an anonymous