From 0f07927a1e80c78fdd924b93496d912f723740da Mon Sep 17 00:00:00 2001 From: kib Date: Sat, 16 May 2015 09:13:56 +0000 Subject: MFC r282679: Do not return from thread_single(SINGLE_BOUNDARY) until all stopped thread are guarenteed to be removed from the processors. --- sys/kern/kern_thread.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) (limited to 'sys/kern/kern_thread.c') diff --git a/sys/kern/kern_thread.c b/sys/kern/kern_thread.c index 8e0146a..ba04471 100644 --- a/sys/kern/kern_thread.c +++ b/sys/kern/kern_thread.c @@ -758,6 +758,29 @@ 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); -- cgit v1.1