Author: kib
Date: Sat May 9 18:32:13 2015
New Revision: 282679
URL: https://svnweb.freebsd.org/changeset/base/282679
Log:
Do not return from thread_single(SINGLE_BOUNDARY) until all stopped
thread are guarenteed to be removed from the processors.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Modified:
head/sys/kern/kern_thread.c
Modified: head/sys/kern/kern_thread.c
==============================================================================
--- head/sys/kern/kern_thread.c Sat May 9 12:28:48 2015 (r282678)
+++ head/sys/kern/kern_thread.c Sat May 9 18:32:13 2015 (r282679)
@@ -759,6 +759,29 @@ stopme:
PROC_LOCK(p);
PROC_SLOCK(p);
}
+ } else if (mode == SINGLE_BOUNDARY) {
+ /*
+ * Wait until all suspended threads are removed from
+ * the processors. The thread_suspend_check()
+ * increments p_boundary_count while it is still
+ * running, which makes it possible for the execve()
+ * to destroy vmspace while our other threads are
+ * still using the address space.
+ *
+ * We lock the thread, which is only allowed to
+ * succeed after context switch code finished using
+ * the address space.
+ */
+ FOREACH_THREAD_IN_PROC(p, td2) {
+ if (td2 == td)
+ continue;
+ thread_lock(td2);
+ KASSERT((td2->td_flags & TDF_BOUNDARY) != 0,
+ ("td %p not on boundary", td2));
+ KASSERT(TD_IS_SUSPENDED(td2),
+ ("td %p is not suspended", td2));
+ thread_unlock(td2);
+ }
}
PROC_SUNLOCK(p);
return (0);
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