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Correct a problem in kmem_malloc: A kmem_malloc allowing "wait" may

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block (VM_WAIT) holding the map lock.  This is bad.  For example, a subsequent
kmem_malloc by an interrupt handler on the same map may find the lock held
and panic in the lockmgr.
This commit is contained in:
Alan Cox 1999-03-16 07:39:07 +00:00
parent 615beb1f86
commit c7003c6991
1 changed files with 5 additions and 3 deletions
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8
sys/vm/vm_kern.c
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@ -61,7 +61,7 @@
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* $Id: vm_kern.c,v 1.52 1999/01/21 09:38:20 dillon Exp $
* $Id: vm_kern.c,v 1.53 1999/03/12 08:05:49 alc Exp $
*/
/*
@ -337,7 +337,9 @@ kmem_malloc(map, size, flags)
*/
if (m == NULL) {
if ((flags & M_NOWAIT) == 0) {
vm_map_unlock(map);
VM_WAIT;
vm_map_lock(map);
goto retry;
}
vm_map_delete(map, addr, addr + size);
@ -359,9 +361,9 @@ kmem_malloc(map, size, flags)
*/
if (!vm_map_lookup_entry(map, addr, &entry) ||
entry->start != addr || entry->end != addr + size ||
entry->wired_count)
entry->wired_count != 0)
panic("kmem_malloc: entry not found or misaligned");
entry->wired_count++;
entry->wired_count = 1;
vm_map_simplify_entry(map, entry);