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If we already had a page with pindex == 0 in the device pager object

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(if not already fictious) the code can panic when trying to first insert
a fictious page because of the overridden pindex.

Fix this by applying the same spinning pattern of vm_page_rename().

Reported by:	pho
This commit is contained in:
attilio 2012-04-07 23:58:49 +00:00
parent a729154742
commit a539d5c569
1 changed files with 7 additions and 5 deletions
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12
sys/vm/device_pager.c
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@ -52,6 +52,8 @@ __FBSDID("$FreeBSD$");
#include <vm/vm_pager.h>
#include <vm/uma.h>
#include <machine/cpu.h>
static void dev_pager_init(void);
static vm_object_t dev_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
vm_ooffset_t, struct ucred *);
@ -259,7 +261,7 @@ old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset, int prot,
struct file *fpop;
struct thread *td;
vm_memattr_t memattr;
int ref, ret;
int i, ref, ret;
pidx = OFF_TO_IDX(offset);
memattr = object->memattr;
@ -307,14 +309,14 @@ old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset, int prot,
*/
page = vm_page_getfake(paddr, memattr);
VM_OBJECT_LOCK(object);
if (vm_page_insert(page, object, offset) != 0) {
vm_page_putfake(page);
return (VM_PAGER_FAIL);
}
vm_page_lock(*mres);
vm_page_free(*mres);
vm_page_unlock(*mres);
*mres = page;
while (vm_page_insert(page, object, offset) != 0) {
for (i = 0; i < 10000000; i++)
cpu_spinwait();
}
}
page->valid = VM_PAGE_BITS_ALL;
return (VM_PAGER_OK);