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Correct the tracking of various bits of the process's vmspace and vm_map

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when not propogated on fork (due to minherit(2)).  Consistency checks
otherwise fail when the vm_map is freed and it appears to have not been
emptied completely, causing an INVARIANTS panic in vm_map_zdtor().

PR:		kern/68017
Submitted by:	Mark W. Krentel <krentel@dreamscape.com>
Reviewed by:	alc
This commit is contained in:
Brian Feldman 2004-06-24 22:43:46 +00:00
parent 12ec7658a4
commit 2a7be1b6d1
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=131073
1 changed files with 44 additions and 3 deletions
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47
sys/vm/vm_map.c
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@ -2341,6 +2341,36 @@ vm_map_copy_entry(
}
}
/*
* vmspace_map_entry_forked:
* Update the newly-forked vmspace each time a map entry is inherited
* or copied. The values for vm_dsize and vm_tsize are approximate
* (and mostly-obsolete ideas in the face of mmap(2) et al.)
*/
static void
vmspace_map_entry_forked(const struct vmspace *vm1, struct vmspace *vm2,
vm_map_entry_t entry)
{
vm_size_t entrysize;
vm_offset_t newend;
entrysize = entry->end - entry->start;
vm2->vm_map.size += entrysize;
if (entry->eflags & (MAP_ENTRY_GROWS_DOWN | MAP_ENTRY_GROWS_UP)) {
vm2->vm_ssize += btoc(entrysize);
} else if (entry->start >= (vm_offset_t)vm1->vm_daddr &&
entry->start < (vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize)) {
newend = min(entry->end,
(vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize));
vm2->vm_dsize += btoc(newend - entry->start);
} else if (entry->start >= (vm_offset_t)vm1->vm_taddr &&
entry->start < (vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize)) {
newend = min(entry->end,
(vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize));
vm2->vm_tsize += btoc(newend - entry->start);
}
}
/*
* vmspace_fork:
* Create a new process vmspace structure and vm_map
@ -2348,6 +2378,8 @@ vm_map_copy_entry(
* is based on the old map, according to the inheritance
* values on the regions in that map.
*
* XXX It might be worth coalescing the entries added to the new vmspace.
*
* The source map must not be locked.
*/
struct vmspace *
@ -2366,8 +2398,16 @@ vmspace_fork(struct vmspace *vm1)
old_map->infork = 1;
vm2 = vmspace_alloc(old_map->min_offset, old_map->max_offset);
bcopy(&vm1->vm_startcopy, &vm2->vm_startcopy,
(caddr_t) &vm1->vm_endcopy - (caddr_t) &vm1->vm_startcopy);
/*
* Using vm_{start,end}copy is invalid for more fields than
* it is valid here. For the most part, initialize size
* fields to zero and update them as map entries are copied
*/
bzero(&vm2->vm_startcopy,
(caddr_t)&vm2->vm_endcopy - (caddr_t)&vm2->vm_startcopy);
vm2->vm_taddr = vm1->vm_taddr;
vm2->vm_daddr = vm1->vm_daddr;
vm2->vm_maxsaddr = vm1->vm_maxsaddr;
new_map = &vm2->vm_map; /* XXX */
new_map->timestamp = 1;
@ -2431,6 +2471,7 @@ vmspace_fork(struct vmspace *vm1)
*/
vm_map_entry_link(new_map, new_map->header.prev,
new_entry);
vmspace_map_entry_forked(vm1, vm2, new_entry);
/*
* Update the physical map
@ -2452,6 +2493,7 @@ vmspace_fork(struct vmspace *vm1)
new_entry->object.vm_object = NULL;
vm_map_entry_link(new_map, new_map->header.prev,
new_entry);
vmspace_map_entry_forked(vm1, vm2, new_entry);
vm_map_copy_entry(old_map, new_map, old_entry,
new_entry);
break;
@ -2459,7 +2501,6 @@ vmspace_fork(struct vmspace *vm1)
old_entry = old_entry->next;
}
new_map->size = old_map->size;
old_map->infork = 0;
vm_map_unlock(old_map);