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Revert r349393, which leads to an assertion failure on bootup, in vm_map_stack_locked.

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Reported by: ler@lerctr.org
Approved by: kib, markj (mentors, implicit)
This commit is contained in:
Doug Moore 2019-06-26 03:12:57 +00:00
parent 1ee03da25e
commit d1d3f7e1d1
2 changed files with 177 additions and 153 deletions
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328
sys/vm/vm_map.c
View File

@ -983,17 +983,6 @@ vm_map_entry_max_free_right(vm_map_entry_t root, vm_map_entry_t right_ancestor)
root->right->max_free : right_ancestor->start - root->end);
}
/*
* vm_map_splay_split, vm_map_splay_merge:
*
* The Sleator and Tarjan top-down splay algorithm with the following
* variation. Max_free must be computed bottom-up, so on the downward
* pass (vm_map_splay_split), maintain the left and right spines in
* reverse order, and ensure that the max_free values for those nodes
* store the values of their descendents not on the search path. Later,
* make a second pass up each side (vm_map_splay_merge) to fix the
* pointers and compute max_free. The time bound is O(log n) amortized.
*/
#define SPLAY_LEFT_STEP(root, y, rlist, test) do { \
vm_size_t max_free; \
\
@ -1176,6 +1165,56 @@ vm_map_splay_merge(vm_map_t map, vm_map_entry_t root,
map->root = root;
}
/*
* vm_map_splay:
*
* The Sleator and Tarjan top-down splay algorithm with the
* following variation. Max_free must be computed bottom-up, so
* on the downward pass, maintain the left and right spines in
* reverse order. Then, make a second pass up each side to fix
* the pointers and compute max_free. The time bound is O(log n)
* amortized.
*
* The new root is the vm_map_entry containing "addr", or else an
* adjacent entry (lower if possible) if addr is not in the tree.
*
* The map must be locked, and leaves it so.
*
* Returns: the new root.
*/
static vm_map_entry_t
vm_map_splay(vm_map_t map, vm_offset_t addr)
{
vm_map_entry_t llist, rlist, root;
root = vm_map_splay_split(map, addr, 0, &llist, &rlist);
if (root != NULL) {
/* do nothing */
} else if (llist != &map->header) {
/*
* Recover the greatest node in the left
* subtree and make it the root.
*/
root = llist;
llist = root->right;
root->right = NULL;
} else if (rlist != &map->header) {
/*
* Recover the least node in the right
* subtree and make it the root.
*/
root = rlist;
rlist = root->left;
root->left = NULL;
} else {
/* There is no root. */
return (NULL);
}
vm_map_splay_merge(map, root, llist, rlist);
VM_MAP_ASSERT_CONSISTENT(map);
return (root);
}
/*
* vm_map_entry_{un,}link:
*
@ -1292,131 +1331,79 @@ vm_map_entry_resize(vm_map_t map, vm_map_entry_t entry, vm_size_t grow_amount)
}
/*
* vm_map_lookup_helper: [ internal use only ]
* vm_map_lookup_entry: [ internal use only ]
*
* Finds the map entry containing (or adjacent to) the specified address
* in the given map; the entry is returned in the "entry" parameter. The
* boolean result indicates whether the address is actually contained in
* the map. If the address is not contained in the map, parameter lesseq
* determines whether the entry provided is before or after the address.
* If the address is contained in the map, parameter nbr, if not NULL, is
* where the next or previous entry is saved, depending on the value of
* eflags in the found entry.
* Finds the map entry containing (or
* immediately preceding) the specified address
* in the given map; the entry is returned
* in the "entry" parameter. The boolean
* result indicates whether the address is
* actually contained in the map.
*/
static bool
vm_map_lookup_helper(vm_map_t map, vm_offset_t addr, bool lesseq,
vm_map_entry_t *entry, vm_map_entry_t *nbr) /* OUT */
boolean_t
vm_map_lookup_entry(
vm_map_t map,
vm_offset_t address,
vm_map_entry_t *entry) /* OUT */
{
vm_map_entry_t llist, rlist, root;
bool locked, found;
vm_map_entry_t cur, lbound;
boolean_t locked;
/*
* If the map is empty, then the map entry immediately preceding
* "addr" is the map's header.
* "address" is the map's header.
*/
root = map->root;
if (root == NULL) {
cur = map->root;
if (cur == NULL) {
*entry = &map->header;
return (false);
return (FALSE);
}
if (address >= cur->start && cur->end > address) {
*entry = cur;
return (TRUE);
}
if ((locked = vm_map_locked(map)) ||
sx_try_upgrade(&map->lock)) {
/*
* Splay requires a write lock on the map. However, it only
* restructures the binary search tree; it does not otherwise
* change the map. Thus, the map's timestamp need not change
* on a temporary upgrade.
*/
root = vm_map_splay_split(map, addr, 0, &llist, &rlist);
found = root != NULL;
*entry = root;
if (root != NULL) {
if (nbr == NULL)
; /* Ignore. */
else if ((root->eflags & MAP_ENTRY_STACK_GAP_DN) != 0) {
vm_map_splay_findnext(root, &rlist);
*nbr = rlist;
} else {
vm_map_splay_findprev(root, &llist);
*nbr = llist;
}
} else if (llist != &map->header) {
/*
* Recover the greatest node in the left
* subtree and make it the root.
*/
*entry = lesseq ? llist : rlist;
root = llist;
llist = root->right;
root->right = NULL;
} else {
/*
* Recover the least node in the right
* subtree and make it the root.
*/
*entry = lesseq ? llist : rlist;
root = rlist;
rlist = root->left;
root->left = NULL;
}
vm_map_splay_merge(map, root, llist, rlist);
VM_MAP_ASSERT_CONSISTENT(map);
cur = vm_map_splay(map, address);
if (!locked)
sx_downgrade(&map->lock);
return (found);
/*
* If "address" is contained within a map entry, the new root
* is that map entry. Otherwise, the new root is a map entry
* immediately before or after "address".
*/
if (address < cur->start) {
*entry = &map->header;
return (FALSE);
}
*entry = cur;
return (address < cur->end);
}
/*
* Since the map is only locked for read access, perform a
* standard binary search tree lookup for "addr".
* standard binary search tree lookup for "address".
*/
llist = rlist = &map->header;
lbound = &map->header;
do {
if (addr < root->start) {
rlist = root;
root = root->left;
} else if (root->end <= addr) {
llist = root;
root = root->right;
if (address < cur->start) {
cur = cur->left;
} else if (cur->end <= address) {
lbound = cur;
cur = cur->right;
} else {
*entry = root;
if (nbr == NULL);
else if ((root->eflags & MAP_ENTRY_STACK_GAP_DN) != 0) {
/* Make nbr the successor to root. */
if (root->right != NULL) {
rlist = root->right;
while (rlist->left != NULL)
rlist = rlist->left;
}
*nbr = rlist;
} else {
/* Make nbr the predecessor to root. */
if (root->left != NULL) {
llist = root->left;
while (llist->right != NULL)
llist = llist->right;
}
*nbr = llist;
}
return (true);
*entry = cur;
return (TRUE);
}
} while (root != NULL);
*entry = lesseq ? llist : rlist;
return (false);
}
bool
vm_map_lookup_entry(vm_map_t map, vm_offset_t addr,
vm_map_entry_t *entry) /* OUT */
{
return (vm_map_lookup_helper(map, addr, true, entry, NULL));
}
static bool
vm_map_lookup_entry_ge(vm_map_t map, vm_offset_t addr,
vm_map_entry_t *entry) /* OUT */
{
return (vm_map_lookup_helper(map, addr, false, entry, NULL));
} while (cur != NULL);
*entry = lbound;
return (FALSE);
}
/*
@ -1435,7 +1422,7 @@ int
vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
vm_offset_t start, vm_offset_t end, vm_prot_t prot, vm_prot_t max, int cow)
{
vm_map_entry_t new_entry, prev_entry;
vm_map_entry_t new_entry, prev_entry, temp_entry;
struct ucred *cred;
vm_eflags_t protoeflags;
vm_inherit_t inheritance;
@ -1460,9 +1447,11 @@ vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
* Find the entry prior to the proposed starting address; if it's part
* of an existing entry, this range is bogus.
*/
if (vm_map_lookup_entry(map, start, &prev_entry))
if (vm_map_lookup_entry(map, start, &temp_entry))
return (KERN_NO_SPACE);
prev_entry = temp_entry;
/*
* Assert that the next entry doesn't overlap the end point.
*/
@ -2325,8 +2314,10 @@ vm_map_submap(
VM_MAP_RANGE_CHECK(map, start, end);
if (vm_map_lookup_entry_ge(map, start, &entry))
if (vm_map_lookup_entry(map, start, &entry)) {
vm_map_clip_start(map, entry, start);
} else
entry = entry->next;
vm_map_clip_end(map, entry, end);
@ -2481,7 +2472,8 @@ again:
VM_MAP_RANGE_CHECK(map, start, end);
vm_map_lookup_entry_ge(map, start, &entry);
if (!vm_map_lookup_entry(map, start, &entry))
entry = entry->next;
/*
* Make a first pass to check for protection violations.
@ -2671,9 +2663,11 @@ vm_map_madvise(
*/
VM_MAP_RANGE_CHECK(map, start, end);
if (vm_map_lookup_entry_ge(map, start, &entry)) {
if (vm_map_lookup_entry(map, start, &entry)) {
if (modify_map)
vm_map_clip_start(map, entry, start);
} else {
entry = entry->next;
}
if (modify_map) {
@ -2805,6 +2799,7 @@ vm_map_inherit(vm_map_t map, vm_offset_t start, vm_offset_t end,
vm_inherit_t new_inheritance)
{
vm_map_entry_t entry;
vm_map_entry_t temp_entry;
switch (new_inheritance) {
case VM_INHERIT_NONE:
@ -2819,8 +2814,11 @@ vm_map_inherit(vm_map_t map, vm_offset_t start, vm_offset_t end,
return (KERN_SUCCESS);
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (vm_map_lookup_entry_ge(map, start, &entry))
if (vm_map_lookup_entry(map, start, &temp_entry)) {
entry = temp_entry;
vm_map_clip_start(map, entry, start);
} else
entry = temp_entry->next;
while (entry->start < end) {
vm_map_clip_end(map, entry, end);
if ((entry->eflags & MAP_ENTRY_GUARD) == 0 ||
@ -2853,8 +2851,10 @@ vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end,
user_unwire = (flags & VM_MAP_WIRE_USER) ? TRUE : FALSE;
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (!vm_map_lookup_entry_ge(map, start, &first_entry)) {
if ((flags & VM_MAP_WIRE_HOLESOK) == 0) {
if (!vm_map_lookup_entry(map, start, &first_entry)) {
if (flags & VM_MAP_WIRE_HOLESOK)
first_entry = first_entry->next;
else {
vm_map_unlock(map);
return (KERN_INVALID_ADDRESS);
}
@ -2882,9 +2882,11 @@ vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end,
* Specifically, the entry may have been
* clipped, merged, or deleted.
*/
if (!vm_map_lookup_entry_ge(map, saved_start,
if (!vm_map_lookup_entry(map, saved_start,
&tmp_entry)) {
if ((flags & VM_MAP_WIRE_HOLESOK) == 0) {
if (flags & VM_MAP_WIRE_HOLESOK)
tmp_entry = tmp_entry->next;
else {
if (saved_start == start) {
/*
* First_entry has been deleted.
@ -2942,9 +2944,11 @@ vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end,
done:
need_wakeup = FALSE;
if (first_entry == NULL) {
result = vm_map_lookup_entry_ge(map, start, &first_entry);
KASSERT(result || (flags & VM_MAP_WIRE_HOLESOK) != 0,
("vm_map_unwire: lookup failed"));
result = vm_map_lookup_entry(map, start, &first_entry);
if (!result && (flags & VM_MAP_WIRE_HOLESOK))
first_entry = first_entry->next;
else
KASSERT(result, ("vm_map_unwire: lookup failed"));
}
for (entry = first_entry; entry->start < end; entry = entry->next) {
/*
@ -3086,8 +3090,10 @@ vm_map_wire_locked(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags)
prot |= VM_PROT_WRITE;
user_wire = (flags & VM_MAP_WIRE_USER) ? TRUE : FALSE;
VM_MAP_RANGE_CHECK(map, start, end);
if (!vm_map_lookup_entry_ge(map, start, &first_entry)) {
if ((flags & VM_MAP_WIRE_HOLESOK) == 0)
if (!vm_map_lookup_entry(map, start, &first_entry)) {
if (flags & VM_MAP_WIRE_HOLESOK)
first_entry = first_entry->next;
else
return (KERN_INVALID_ADDRESS);
}
last_timestamp = map->timestamp;
@ -3113,9 +3119,11 @@ vm_map_wire_locked(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags)
* Specifically, the entry may have been
* clipped, merged, or deleted.
*/
if (!vm_map_lookup_entry_ge(map, saved_start,
if (!vm_map_lookup_entry(map, saved_start,
&tmp_entry)) {
if ((flags & VM_MAP_WIRE_HOLESOK) == 0) {
if (flags & VM_MAP_WIRE_HOLESOK)
tmp_entry = tmp_entry->next;
else {
if (saved_start == start) {
/*
* first_entry has been deleted.
@ -3248,9 +3256,11 @@ vm_map_wire_locked(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags)
done:
need_wakeup = FALSE;
if (first_entry == NULL) {
result = vm_map_lookup_entry_ge(map, start, &first_entry);
KASSERT(result || (flags & VM_MAP_WIRE_HOLESOK) != 0,
("vm_map_wire: lookup failed"));
result = vm_map_lookup_entry(map, start, &first_entry);
if (!result && (flags & VM_MAP_WIRE_HOLESOK))
first_entry = first_entry->next;
else
KASSERT(result, ("vm_map_wire: lookup failed"));
}
for (entry = first_entry; entry->start < end; entry = entry->next) {
/*
@ -3351,8 +3361,7 @@ vm_map_sync(
if (!vm_map_lookup_entry(map, start, &entry)) {
vm_map_unlock_read(map);
return (KERN_INVALID_ADDRESS);
}
if (start == end) {
} else if (start == end) {
start = entry->start;
end = entry->end;
}
@ -3407,10 +3416,9 @@ vm_map_sync(
start += size;
vm_object_deallocate(object);
vm_map_lock_read(map);
if (last_timestamp == map->timestamp)
if (last_timestamp == map->timestamp ||
!vm_map_lookup_entry(map, start, &current))
current = current->next;
else
vm_map_lookup_entry_ge(map, start, &current);
}
vm_map_unlock_read(map);
@ -3543,6 +3551,7 @@ int
vm_map_delete(vm_map_t map, vm_offset_t start, vm_offset_t end)
{
vm_map_entry_t entry;
vm_map_entry_t first_entry;
VM_MAP_ASSERT_LOCKED(map);
if (start == end)
@ -3551,8 +3560,12 @@ vm_map_delete(vm_map_t map, vm_offset_t start, vm_offset_t end)
/*
* Find the start of the region, and clip it
*/
if (vm_map_lookup_entry_ge(map, start, &entry))
if (!vm_map_lookup_entry(map, start, &first_entry))
entry = first_entry->next;
else {
entry = first_entry;
vm_map_clip_start(map, entry, start);
}
/*
* Step through all entries in this region
@ -3570,22 +3583,29 @@ vm_map_delete(vm_map_t map, vm_offset_t start, vm_offset_t end)
vm_map_entry_system_wired_count(entry) != 0)) {
unsigned int last_timestamp;
vm_offset_t saved_start;
vm_map_entry_t tmp_entry;
saved_start = entry->start;
entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP;
last_timestamp = map->timestamp;
(void) vm_map_unlock_and_wait(map, 0);
vm_map_lock(map);
if (last_timestamp + 1 == map->timestamp)
continue;
/*
* Look again for the entry because the map was
* modified while it was unlocked. Specifically, the
* entry may have been clipped, merged, or deleted.
*/
if (vm_map_lookup_entry_ge(map, saved_start, &entry))
vm_map_clip_start(map, entry, saved_start);
if (last_timestamp + 1 != map->timestamp) {
/*
* Look again for the entry because the map was
* modified while it was unlocked.
* Specifically, the entry may have been
* clipped, merged, or deleted.
*/
if (!vm_map_lookup_entry(map, saved_start,
&tmp_entry))
entry = tmp_entry->next;
else {
entry = tmp_entry;
vm_map_clip_start(map, entry,
saved_start);
}
}
continue;
}
vm_map_clip_end(map, entry, end);
@ -3660,9 +3680,11 @@ vm_map_check_protection(vm_map_t map, vm_offset_t start, vm_offset_t end,
vm_prot_t protection)
{
vm_map_entry_t entry;
vm_map_entry_t tmp_entry;
if (!vm_map_lookup_entry(map, start, &entry))
if (!vm_map_lookup_entry(map, start, &tmp_entry))
return (FALSE);
entry = tmp_entry;
while (start < end) {
/*
@ -4098,7 +4120,7 @@ static int
vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize,
vm_size_t growsize, vm_prot_t prot, vm_prot_t max, int cow)
{
vm_map_entry_t new_entry;
vm_map_entry_t new_entry, prev_entry;
vm_offset_t bot, gap_bot, gap_top, top;
vm_size_t init_ssize, sgp;
int orient, rv;
@ -4126,13 +4148,13 @@ vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize,
init_ssize = max_ssize - sgp;
/* If addr is already mapped, no go */
if (vm_map_lookup_entry_ge(map, addrbos, &new_entry))
if (vm_map_lookup_entry(map, addrbos, &prev_entry))
return (KERN_NO_SPACE);
/*
* If we can't accommodate max_ssize in the current mapping, no go.
*/
if (new_entry->start < addrbos + max_ssize)
if (prev_entry->next->start < addrbos + max_ssize)
return (KERN_NO_SPACE);
/*
@ -4159,6 +4181,7 @@ vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize,
rv = vm_map_insert(map, NULL, 0, bot, top, prot, max, cow);
if (rv != KERN_SUCCESS)
return (rv);
new_entry = prev_entry->next;
KASSERT(new_entry->end == top || new_entry->start == bot,
("Bad entry start/end for new stack entry"));
KASSERT((orient & MAP_STACK_GROWS_DOWN) == 0 ||
@ -4217,18 +4240,19 @@ vm_map_growstack(vm_map_t map, vm_offset_t addr, vm_map_entry_t gap_entry)
vmemlim = lim_cur(curthread, RLIMIT_VMEM);
retry:
/* If addr is not in a hole for a stack grow area, no need to grow. */
if (gap_entry == NULL &&
!vm_map_lookup_helper(map, addr, true, &gap_entry, &stack_entry))
if (gap_entry == NULL && !vm_map_lookup_entry(map, addr, &gap_entry))
return (KERN_FAILURE);
if ((gap_entry->eflags & MAP_ENTRY_GUARD) == 0)
return (KERN_SUCCESS);
if ((gap_entry->eflags & MAP_ENTRY_STACK_GAP_DN) != 0) {
stack_entry = gap_entry->next;
if ((stack_entry->eflags & MAP_ENTRY_GROWS_DOWN) == 0 ||
stack_entry->start != gap_entry->end)
return (KERN_FAILURE);
grow_amount = round_page(stack_entry->start - addr);
grow_down = true;
} else if ((gap_entry->eflags & MAP_ENTRY_STACK_GAP_UP) != 0) {
stack_entry = gap_entry->prev;
if ((stack_entry->eflags & MAP_ENTRY_GROWS_UP) == 0 ||
stack_entry->end != gap_entry->start)
return (KERN_FAILURE);

2
sys/vm/vm_map.h
View File

@ -415,7 +415,7 @@ int vm_map_lookup (vm_map_t *, vm_offset_t, vm_prot_t, vm_map_entry_t *, vm_obje
int vm_map_lookup_locked(vm_map_t *, vm_offset_t, vm_prot_t, vm_map_entry_t *, vm_object_t *,
vm_pindex_t *, vm_prot_t *, boolean_t *);
void vm_map_lookup_done (vm_map_t, vm_map_entry_t);
bool vm_map_lookup_entry(vm_map_t, vm_offset_t, vm_map_entry_t *);
boolean_t vm_map_lookup_entry (vm_map_t, vm_offset_t, vm_map_entry_t *);
int vm_map_protect (vm_map_t, vm_offset_t, vm_offset_t, vm_prot_t, boolean_t);
int vm_map_remove (vm_map_t, vm_offset_t, vm_offset_t);
void vm_map_simplify_entry(vm_map_t map, vm_map_entry_t entry);