Date: Wed, 26 Sep 2012 03:54:55 +0000 (UTC) From: Alan Cox <alc@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-9@freebsd.org Subject: svn commit: r240947 - stable/9/sys/vm Message-ID: <201209260354.q8Q3stwH048142@svn.freebsd.org>
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Author: alc Date: Wed Sep 26 03:54:55 2012 New Revision: 240947 URL: http://svn.freebsd.org/changeset/base/240947 Log: MFC r240862 Address a race condition that was introduced in r238212. Unless the page queues lock is acquired before the page lock is released, there is no guarantee that the page will still be in that same page queue when vm_page_requeue() is called. Modified: stable/9/sys/vm/vm_pageout.c Directory Properties: stable/9/sys/ (props changed) Modified: stable/9/sys/vm/vm_pageout.c ============================================================================== --- stable/9/sys/vm/vm_pageout.c Wed Sep 26 03:45:42 2012 (r240946) +++ stable/9/sys/vm/vm_pageout.c Wed Sep 26 03:54:55 2012 (r240947) @@ -999,9 +999,9 @@ vm_pageout_scan(int pass) * Those objects are in a "rundown" state. */ if (!swap_pageouts_ok || (object->flags & OBJ_DEAD)) { + vm_page_lock_queues(); vm_page_unlock(m); VM_OBJECT_UNLOCK(object); - vm_page_lock_queues(); queues_locked = TRUE; vm_page_requeue(m); goto relock_queues;
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