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Synchronize vm map and object accesses.

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Approved by: des@
This commit is contained in:
Alan Cox 2007-05-01 03:09:57 +00:00
parent 712fc218a0
commit 4bd4f5a2e2
1 changed files with 26 additions and 8 deletions
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34
sys/compat/linprocfs/linprocfs.c
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@ -860,12 +860,14 @@ linprocfs_doprocmaps(PFS_FILL_ARGS)
{
char mebuffer[512];
vm_map_t map = &p->p_vmspace->vm_map;
vm_map_entry_t entry;
vm_map_entry_t entry, tmp_entry;
vm_object_t obj, tobj, lobj;
vm_offset_t saved_end;
vm_ooffset_t off = 0;
char *name = "", *freename = NULL;
size_t len;
ino_t ino;
unsigned int last_timestamp;
int ref_count, shadow_count, flags;
int error;
struct vnode *vp;
@ -885,8 +887,7 @@ linprocfs_doprocmaps(PFS_FILL_ARGS)
return (0);
error = 0;
if (map != &curthread->td_proc->p_vmspace->vm_map)
vm_map_lock_read(map);
vm_map_lock_read(map);
for (entry = map->header.next;
((uio->uio_resid > 0) && (entry != &map->header));
entry = entry->next) {
@ -894,12 +895,16 @@ linprocfs_doprocmaps(PFS_FILL_ARGS)
freename = NULL;
if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)
continue;
saved_end = entry->end;
obj = entry->object.vm_object;
for (lobj = tobj = obj; tobj; tobj = tobj->backing_object)
for (lobj = tobj = obj; tobj; tobj = tobj->backing_object) {
VM_OBJECT_LOCK(tobj);
if (lobj != obj)
VM_OBJECT_UNLOCK(lobj);
lobj = tobj;
}
ino = 0;
if (lobj) {
VM_OBJECT_LOCK(lobj);
off = IDX_TO_OFF(lobj->size);
if (lobj->type == OBJT_VNODE) {
vp = lobj->handle;
@ -908,10 +913,12 @@ linprocfs_doprocmaps(PFS_FILL_ARGS)
}
else
vp = NULL;
if (lobj != obj)
VM_OBJECT_UNLOCK(lobj);
flags = obj->flags;
ref_count = obj->ref_count;
shadow_count = obj->shadow_count;
VM_OBJECT_UNLOCK(lobj);
VM_OBJECT_UNLOCK(obj);
if (vp) {
vn_fullpath(td, vp, &name, &freename);
locked = VFS_LOCK_GIANT(vp->v_mount);
@ -953,12 +960,23 @@ linprocfs_doprocmaps(PFS_FILL_ARGS)
* XXX We should probably return
* EFBIG here, as in procfs.
*/
last_timestamp = map->timestamp;
vm_map_unlock_read(map);
error = uiomove(mebuffer, len, uio);
vm_map_lock_read(map);
if (error)
break;
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.
*/
vm_map_lookup_entry(map, saved_end - 1, &tmp_entry);
entry = tmp_entry;
}
}
if (map != &curthread->td_proc->p_vmspace->vm_map)
vm_map_unlock_read(map);
vm_map_unlock_read(map);
return (error);
}