d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Obtain Giant before calling kmem_alloc without M_NOWAIT and before calling

Browse Source 
kmem_free if Giant isn't already held.
This commit is contained in:
tegge 2003-03-26 18:44:53 +00:00
parent 72a1a2619c
commit 5a1c871266
1 changed files with 21 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
sys/vm/uma_core.c
View File

@ -2017,7 +2017,13 @@ uma_large_malloc(int size, int wait)
if (slab == NULL)
return (NULL);
mem = page_alloc(NULL, size, &flags, wait);
/* XXX: kmem_malloc panics if Giant isn't held and sleep allowed */
if ((wait & M_NOWAIT) == 0 && !mtx_owned(&Giant)) {
mtx_lock(&Giant);
mem = page_alloc(NULL, size, &flags, wait);
mtx_unlock(&Giant);
} else
mem = page_alloc(NULL, size, &flags, wait);
if (mem) {
vsetslab((vm_offset_t)mem, slab);
slab->us_data = mem;
@ -2035,7 +2041,20 @@ void
uma_large_free(uma_slab_t slab)
{
vsetobj((vm_offset_t)slab->us_data, kmem_object);
page_free(slab->us_data, slab->us_size, slab->us_flags);
/*
* XXX: Giant is still needed by kmem_free, since we have
* kmem_free -> vm_map_remove -> vm_map_delete ->
* vm_object_page_remove -> vm_object_pip_add -> GIANT_REQUIRED
* We also get a lock order reversal if we don't have Giant:
* vm_map_remove (locks system map) -> vm_map_delete ->
* vm_map_entry_unwire -> vm_fault_unwire -> mtx_lock(&Giant)
*/
if (!mtx_owned(&Giant)) {
mtx_lock(&Giant);
page_free(slab->us_data, slab->us_size, slab->us_flags);
mtx_unlock(&Giant);
} else
page_free(slab->us_data, slab->us_size, slab->us_flags);
uma_zfree_internal(slabzone, slab, NULL, 0);
}