[PATCH v7 09/70] mm: Start tracking VMAs with maple tree

From: Liam Howlett
Date: Mon Apr 04 2022 - 10:38:06 EST

From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>

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.

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
---
arch/x86/kernel/tboot.c | 1 +
drivers/firmware/efi/efi.c | 1 +
include/linux/mm.h | 2 +
include/linux/mm_types.h | 3 +
include/trace/events/mmap.h | 71 +++++++++++++
kernel/fork.c | 5 +
mm/init-mm.c | 2 +
mm/internal.h | 70 +++++++++++++
mm/mmap.c | 202 +++++++++++++++++++++++++++++++++++-
9 files changed, 355 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
index f9af561c3cd4..859e8d2ea070 100644
--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -98,6 +98,7 @@ 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),
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 5502e176d51b..92a765d8d3b6 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -55,6 +55,7 @@ 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),
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e34edb775334..d21e4fdbe1a0 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2577,6 +2577,8 @@ 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_store(struct mm_struct *mm, struct vm_area_struct *vma);

/* interval_tree.c */
void vma_interval_tree_insert(struct vm_area_struct *node,
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 8834e38c06a4..5efd9a095de4 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -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>
@@ -476,6 +477,7 @@ 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
@@ -664,6 +666,7 @@ 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. */
diff --git a/include/trace/events/mmap.h b/include/trace/events/mmap.h
index 4661f7ba07c0..f5c1626f3bbb 100644
--- a/include/trace/events/mmap.h
+++ b/include/trace/events/mmap.h
@@ -42,6 +42,77 @@ TRACE_EVENT(vm_unmapped_area,
__entry->low_limit, __entry->high_limit, __entry->align_mask,
__entry->align_offset)
);
+
+TRACE_EVENT(vma_mt_szero,
+ TP_PROTO(struct mm_struct *mm, unsigned long start,
+ unsigned long end),
+
+ TP_ARGS(mm, start, end),
+
+ TP_STRUCT__entry(
+ __field(struct mm_struct *, mm)
+ __field(unsigned long, start)
+ __field(unsigned long, end)
+ ),
+
+ TP_fast_assign(
+ __entry->mm = mm;
+ __entry->start = start;
+ __entry->end = end - 1;
+ ),
+
+ TP_printk("mt_mod %p, (NULL), SNULL, %lu, %lu,",
+ __entry->mm,
+ (unsigned long) __entry->start,
+ (unsigned long) __entry->end
+ )
+);
+
+TRACE_EVENT(vma_store,
+ TP_PROTO(struct mm_struct *mm, struct vm_area_struct *vma),
+
+ TP_ARGS(mm, vma),
+
+ TP_STRUCT__entry(
+ __field(struct mm_struct *, mm)
+ __field(struct vm_area_struct *, vma)
+ __field(unsigned long, vm_start)
+ __field(unsigned long, vm_end)
+ ),
+
+ TP_fast_assign(
+ __entry->mm = mm;
+ __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->mm, __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)
+ ),
+
+ TP_fast_assign(
+ __entry->mm = mm;
+ ),
+
+ TP_printk("mt_mod %p, DESTROY\n",
+ __entry->mm
+ )
+);
+
#endif

/* This part must be outside protection */
diff --git a/kernel/fork.c b/kernel/fork.c
index 9796897560ab..c81993dff42c 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -696,6 +696,9 @@ 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 */
+ vma_store(mm, tmp);
+
mm->map_count++;
if (!(tmp->vm_flags & VM_WIPEONFORK))
retval = copy_page_range(tmp, mpnt);
@@ -1107,6 +1110,8 @@ 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);
diff --git a/mm/init-mm.c b/mm/init-mm.c
index fbe7844d0912..b912b0f2eced 100644
--- a/mm/init-mm.c
+++ b/mm/init-mm.c
@@ -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),
diff --git a/mm/internal.h b/mm/internal.h
index cf16280ce132..8221f290d047 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -394,6 +394,76 @@ static inline bool is_data_mapping(vm_flags_t flags)
return (flags & (VM_WRITE | VM_SHARED | VM_STACK)) == VM_WRITE;
}

+/* Maple tree operations using VMAs */
+/*
+ * 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.
+ */
+static inline int vma_mas_store(struct vm_area_struct *vma, struct ma_state *mas)
+{
+#ifdef CONFIG_DEBUG_VM_MAPLE_TREE
+ /* Make sure no VMAs are about to be lost. */
+ MA_STATE(test, mas->tree, vma->vm_start, vma->vm_end - 1);
+ struct vm_area_struct *vma_mas;
+ int count = 0;
+
+ mas_for_each(&test, vma_mas, vma->vm_end - 1) {
+ /* Rule out vma_expand */
+ if ((vma->vm_start != vma_mas->vm_start) &&
+ (vma->vm_end != vma_mas->vm_end))
+ count++;
+ }
+
+ /* vma adjust may overwrite a partial entry or remove one */
+ BUG_ON(count > 1);
+
+ BUG_ON(mas->min > vma->vm_start);
+ BUG_ON(mas->index > vma->vm_start);
+#endif
+ mas->index = vma->vm_start;
+ mas->last = vma->vm_end - 1;
+ return mas_store_gfp(mas, vma, GFP_KERNEL);
+}
+
+/*
+ * 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.
+ */
+static inline int vma_mas_remove(struct vm_area_struct *vma, struct ma_state *mas)
+{
+ int ret;
+
+#ifdef CONFIG_DEBUG_VM_MAPLE_TREE
+ /* Make sure no VMAs are about to be lost. */
+ MA_STATE(test, mas->tree, vma->vm_start, vma->vm_end - 1);
+ struct vm_area_struct *vma_mas;
+ int count = 0;
+
+ mas_for_each(&test, vma_mas, vma->vm_end - 1)
+ count++;
+
+ BUG_ON(count != 1);
+
+ BUG_ON(mas->min > vma->vm_start);
+ BUG_ON(mas->min > mas->index);
+#endif
+ mas->index = vma->vm_start;
+ mas->last = vma->vm_end - 1;
+ ret = mas_store_gfp(mas, NULL, GFP_KERNEL);
+ return ret;
+}
+
/* mm/util.c */
void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
struct vm_area_struct *prev);
diff --git a/mm/mmap.c b/mm/mmap.c
index 3aa839f81e63..ebdee54b92e3 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -376,7 +376,70 @@ 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);
+ 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: %px %lu - %lu\n", vma_mt,
+ mas.index, mas.last);
+ pr_emerg("mt vma: %px %lu - %lu\n", vma_mt,
+ vma_mt->vm_start, vma_mt->vm_end);
+ pr_emerg("rb vma: %px %lu - %lu\n", vma,
+ vma->vm_start, vma->vm_end);
+ pr_emerg("rb->next = %px %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: %px 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: %px vma_mt %px %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);
+ mt_validate(&mm->mm_mt);
+}
+#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;
@@ -431,6 +494,7 @@ 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

@@ -675,11 +739,42 @@ static void __vma_link_file(struct vm_area_struct *vma)
}
}

+/*
+ * vma_mt_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_mt_szero(struct mm_struct *mm, unsigned long start,
+ unsigned long end)
+{
+ MA_STATE(mas, &mm->mm_mt, start, end - 1);
+
+ trace_vma_mt_szero(mm, start, end);
+ mas_store_gfp(&mas, NULL, GFP_KERNEL);
+}
+
+/*
+ * vma_store() - Store a given vm_area_struct in the maple tree.
+ * @mm: The struct_mm
+ * @vma: The vm_area_struct to store in the maple tree.
+ */
+void vma_store(struct mm_struct *mm, struct vm_area_struct *vma)
+{
+ MA_STATE(mas, &mm->mm_mt, 0, 0);
+
+ trace_vma_store(vma->vm_mm, vma);
+ vma_mas_store(vma, &mas);
+}
+
static void
__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)
{
+ vma_store(mm, vma);
__vma_link_list(mm, vma, prev);
__vma_link_rb(mm, vma, rb_link, rb_parent);
}
@@ -752,6 +847,9 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
long adjust_next = 0;
int remove_next = 0;

+ validate_mm(mm);
+ validate_mm_mt(mm);
+
if (next && !insert) {
struct vm_area_struct *exporter = NULL, *importer = NULL;

@@ -877,17 +975,28 @@ 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_mt_szero(mm, 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_mt_szero(mm, end, old_end);
end_changed = true;
}
+
+ if (end_changed || start_changed)
+ vma_store(mm, vma);
+
vma->vm_pgoff = pgoff;
if (adjust_next) {
next->vm_start += adjust_next;
next->vm_pgoff += adjust_next >> PAGE_SHIFT;
+ vma_store(mm, next);
}

if (file) {
@@ -901,6 +1010,8 @@ 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)
__vma_unlink(mm, next, next);
@@ -1020,6 +1131,7 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
uprobe_mmap(insert);

validate_mm(mm);
+ validate_mm_mt(mm);

return 0;
}
@@ -1173,6 +1285,7 @@ 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.
@@ -1248,6 +1361,7 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
khugepaged_enter_vma_merge(area, vm_flags);
return area;
}
+ validate_mm_mt(mm);

return NULL;
}
@@ -1727,6 +1841,7 @@ 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;
@@ -1874,6 +1989,7 @@ 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:
@@ -1890,6 +2006,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
unacct_error:
if (charged)
vm_unacct_memory(charged);
+ validate_mm_mt(mm);
return error;
}

@@ -1906,12 +2023,19 @@ 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;
@@ -1993,20 +2117,31 @@ 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().
@@ -2092,6 +2227,32 @@ 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: %px 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 => %px (%px)\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) {
+ printk("vma %px %lu-%lu\n", dv, dv->vm_start, dv->vm_end);
+ dv = dv->vm_next;
+ }
+ }
+ VM_BUG_ON(gap != gap_end);
+ }
+
return gap_end;
}

@@ -2305,7 +2466,6 @@ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
vmacache_update(addr, vma);
return vma;
}
-
EXPORT_SYMBOL(find_vma);

/*
@@ -2386,6 +2546,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
unsigned long gap_addr;
int error = 0;

+ validate_mm_mt(mm);
if (!(vma->vm_flags & VM_GROWSUP))
return -EFAULT;

@@ -2448,6 +2609,8 @@ 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_store(mm, vma);
anon_vma_interval_tree_post_update_vma(vma);
if (vma->vm_next)
vma_gap_update(vma->vm_next);
@@ -2462,6 +2625,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
anon_vma_unlock_write(vma->anon_vma);
khugepaged_enter_vma_merge(vma, vma->vm_flags);
validate_mm(mm);
+ validate_mm_mt(mm);
return error;
}
#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
@@ -2476,6 +2640,7 @@ int expand_downwards(struct vm_area_struct *vma,
struct vm_area_struct *prev;
int error = 0;

+ validate_mm(mm);
address &= PAGE_MASK;
if (address < mmap_min_addr)
return -EPERM;
@@ -2529,6 +2694,8 @@ 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_store(mm, vma);
anon_vma_interval_tree_post_update_vma(vma);
vma_gap_update(vma);
spin_unlock(&mm->page_table_lock);
@@ -2670,6 +2837,7 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,

insertion_point = (prev ? &prev->vm_next : &mm->mmap);
vma->vm_prev = NULL;
+ vma_mt_szero(mm, vma->vm_start, end);
do {
vma_rb_erase(vma, &mm->mm_rb);
if (vma->vm_flags & VM_LOCKED)
@@ -2710,6 +2878,7 @@ 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);
@@ -2762,6 +2931,7 @@ 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;
}

@@ -3010,6 +3180,7 @@ 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)
@@ -3067,6 +3238,7 @@ 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;
}

@@ -3158,6 +3330,8 @@ void exit_mmap(struct mm_struct *mm)
}
mm->mmap = NULL;
mmap_write_unlock(mm);
+ trace_exit_mmap(mm);
+ __mt_destroy(&mm->mm_mt);
vm_unacct_memory(nr_accounted);
}

@@ -3169,10 +3343,25 @@ 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;

if (find_vma_links(mm, vma->vm_start, vma->vm_end,
&prev, &rb_link, &rb_parent))
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)))
return -ENOMEM;
@@ -3212,7 +3401,9 @@ 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.
@@ -3224,6 +3415,8 @@ 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));
@@ -3267,6 +3460,7 @@ 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:
@@ -3274,6 +3468,7 @@ 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;
}

@@ -3410,6 +3605,7 @@ 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);
@@ -3432,10 +3628,12 @@ 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);
}

--
2.34.1