Date: Sat, 24 Jun 2017 16:47:41 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r320316 - head/sys/vm Message-ID: <201706241647.v5OGlfPn009252@repo.freebsd.org>
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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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