Date: Thu, 11 Jul 2013 05:58:29 +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: r253191 - head/sys/vm Message-ID: <201307110558.r6B5wT6x045772@svn.freebsd.org>
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Author: kib Date: Thu Jul 11 05:58:28 2013 New Revision: 253191 URL: http://svnweb.freebsd.org/changeset/base/253191 Log: The vm_fault() should not be allowed to proceed on the map entry which is being wired now. The entry wired count is changed to non-zero in advance, before the map lock is dropped. This makes the vm_fault() to perceive the entry as wired, and breaks the fragment which moves the wire count from the shadowed page, to the upper page, making the code unwiring non-wired page. On the other hand, the vm_fault() calls from vm_fault_wire() should be allowed to proceed, so only drain MAP_ENTRY_IN_TRANSITION from vm_fault() when wiring_thread is not current. Reported and tested by: pho Reviewed by: alc Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Modified: head/sys/vm/vm_fault.c Modified: head/sys/vm/vm_fault.c ============================================================================== --- head/sys/vm/vm_fault.c Thu Jul 11 05:55:08 2013 (r253190) +++ head/sys/vm/vm_fault.c Thu Jul 11 05:58:28 2013 (r253191) @@ -280,6 +280,19 @@ RetryFault:; (u_long)vaddr); } + if (fs.entry->eflags & MAP_ENTRY_IN_TRANSITION && + fs.entry->wiring_thread != curthread) { + vm_map_unlock_read(fs.map); + vm_map_lock(fs.map); + if (vm_map_lookup_entry(fs.map, vaddr, &fs.entry) && + (fs.entry->eflags & MAP_ENTRY_IN_TRANSITION)) { + fs.entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; + vm_map_unlock_and_wait(fs.map, 0); + } else + vm_map_unlock(fs.map); + goto RetryFault; + } + /* * Make a reference to this object to prevent its disposal while we * are messing with it. Once we have the reference, the map is free
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