Author: kib
Date: Sat Jun 24 16:47:41 2017
New Revision: 320316
URL: https://svnweb.freebsd.org/changeset/base/320316
Log:
Do not try to unmark MAP_ENTRY_IN_TRANSITION marked by other thread.
The issue is catched by "vm_map_wire: alien wire" KASSERT at the end
of the vm_map_wire(). We currently check for MAP_ENTRY_WIRE_SKIPPED
flag before ensuring that the wiring_thread is curthread. For HOLESOK
wiring, this means that we might see WIRE_SKIPPED entry from different
wiring.
The fix it by only checking WIRE_SKIPPED if the entry is put
IN_TRANSITION by us. Also fixed a typo in the comment explaining the
situation.
Reported and tested by: pho
Reviewed by: alc
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Modified:
head/sys/vm/vm_map.c
Modified: head/sys/vm/vm_map.c
==============================================================================
--- head/sys/vm/vm_map.c Sat Jun 24 16:41:26 2017 (r320315)
+++ head/sys/vm/vm_map.c Sat Jun 24 16:47:41 2017 (r320316)
@@ -2712,9 +2712,6 @@ done:
}
for (entry = first_entry; entry != &map->header && entry->start < end;
entry = entry->next) {
- if ((entry->eflags & MAP_ENTRY_WIRE_SKIPPED) != 0)
- goto next_entry_done;
-
/*
* If VM_MAP_WIRE_HOLESOK was specified, an empty
* space in the unwired region could have been mapped
@@ -2722,7 +2719,7 @@ done:
* pages or draining MAP_ENTRY_IN_TRANSITION.
* Moreover, another thread could be simultaneously
* wiring this new mapping entry. Detect these cases
- * and skip any entries marked as in transition by us.
+ * and skip any entries marked as in transition not by us.
*/
if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 ||
entry->wiring_thread != curthread) {
@@ -2730,6 +2727,9 @@ done:
("vm_map_wire: !HOLESOK and new/changed entry"));
continue;
}
+
+ if ((entry->eflags & MAP_ENTRY_WIRE_SKIPPED) != 0)
+ goto next_entry_done;
if (rv == KERN_SUCCESS) {
if (user_wire)
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