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- Avoid a lock-order reversal between Giant and a system map mutex that

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occurs when kmem_malloc() fails to allocate a sufficient number of vm
   pages.  Specifically, we avoid the lock-order reversal by not grabbing
   Giant around pmap_remove() if the map is the kmem_map.

Approved by:	re (jhb)
Reported by:	Eugene <eugene3@web.de>
This commit is contained in:
Alan Cox 2003-11-19 18:48:45 +00:00
parent b8aeddf146
commit 1cd5fbd854
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=122902
1 changed files with 4 additions and 2 deletions
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6
sys/vm/vm_map.c
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@ -2173,11 +2173,13 @@ vm_map_delete(vm_map_t map, vm_offset_t start, vm_offset_t end)
vm_map_entry_unwire(map, entry);
}
mtx_lock(&Giant);
if (map != kmem_map)
mtx_lock(&Giant);
vm_page_lock_queues();
pmap_remove(map->pmap, entry->start, entry->end);
vm_page_unlock_queues();
mtx_unlock(&Giant);
if (map != kmem_map)
mtx_unlock(&Giant);
/*
* Delete the entry (which may delete the object) only after