Date: Sun, 24 Nov 2019 06:46:49 +0000 (UTC) From: Doug Moore <dougm@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r355048 - stable/12/sys/vm Message-ID: <201911240646.xAO6kn33046488@repo.freebsd.org>
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Author: dougm Date: Sun Nov 24 06:46:49 2019 New Revision: 355048 URL: https://svnweb.freebsd.org/changeset/base/355048 Log: MFC r354785 The loop in vm_map_protect that verifies that all transition map entries are stabilized, repeatedly verifies the same entry. Check each entry in turn. Modified: stable/12/sys/vm/vm_map.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/vm/vm_map.c ============================================================================== --- stable/12/sys/vm/vm_map.c Sun Nov 24 06:43:03 2019 (r355047) +++ stable/12/sys/vm/vm_map.c Sun Nov 24 06:46:49 2019 (r355048) @@ -2496,17 +2496,16 @@ again: vm_map_unlock(map); return (KERN_PROTECTION_FAILURE); } - if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0) - in_tran = entry; + if ((current->eflags & MAP_ENTRY_IN_TRANSITION) != 0) + in_tran = current; } /* - * Postpone the operation until all in transition map entries - * are stabilized. In-transition entry might already have its - * pages wired and wired_count incremented, but - * MAP_ENTRY_USER_WIRED flag not yet set, and visible to other - * threads because the map lock is dropped. In this case we - * would miss our call to vm_fault_copy_entry(). + * Postpone the operation until all in-transition map entries have + * stabilized. An in-transition entry might already have its pages + * wired and wired_count incremented, but not yet have its + * MAP_ENTRY_USER_WIRED flag set. In which case, we would fail to call + * vm_fault_copy_entry() in the final loop below. */ if (in_tran != NULL) { in_tran->eflags |= MAP_ENTRY_NEEDS_WAKEUP;
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