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Fix a recursive kernel_map lock problem in vm_zone allocator.

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PR:	5298
This commit is contained in:
John Dyson 1997-12-15 05:16:09 +00:00
parent 5fa1e123e1
commit bd28588799
1 changed files with 22 additions and 18 deletions
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40
sys/vm/vm_zone.c
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@ -18,7 +18,7 @@
* 5. Modifications may be freely made to this file if the above conditions
* are met.
*
* $Id: vm_zone.c,v 1.11 1997/12/05 19:55:52 bde Exp $
* $Id: vm_zone.c,v 1.12 1997/12/14 05:17:41 dyson Exp $
*/
#include <sys/param.h>
@ -32,6 +32,7 @@
#include <vm/vm_object.h>
#include <vm/vm_prot.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#include <vm/vm_zone.h>
@ -304,26 +305,29 @@ _zget(vm_zone_t z)
nitems = (i * PAGE_SIZE) / z->zsize;
} else {
nbytes = z->zalloc * PAGE_SIZE;
/*
* We can wait, so just do normal kernel map allocation
* Check to see if the kernel map is already locked. We could allow
* for recursive locks, but that eliminates a valuable debugging
* mechanism, and opens up the kernel map for potential corruption
* by inconsistent data structure manipulation. We could also use
* the interrupt allocation mechanism, but that has size limitations.
* Luckily, we have kmem_map that is a submap of kernel map available
* for memory allocation, and manipulation of that map doesn't affect
* the kernel map structures themselves.
*
* We can wait, so just do normal map allocation in the appropriate
* map.
*/
item = (void *) kmem_alloc(kernel_map, nbytes);
if (lockstatus(&kernel_map->lock)) {
int s;
s = splhigh();
item = (void *) kmem_malloc(kmem_map, nbytes, M_WAITOK);
splx(s);
} else {
item = (void *) kmem_alloc(kernel_map, nbytes);
}
#if 0
if (z->zname)
printf("zalloc: %s, %d (0x%x --> 0x%x)\n",
z->zname, z->zalloc, item,
(char *)item + nbytes);
else
printf("zalloc: XXX(%d), %d (0x%x --> 0x%x)\n",
z->zsize, z->zalloc, item,
(char *)item + nbytes);
for (i = 0; i < nbytes; i += PAGE_SIZE)
printf("(%x, %x)", (char *) item + i,
pmap_kextract((char *) item + i));
printf("\n");
#endif
nitems = nbytes / z->zsize;
}
z->ztotal += nitems;