Date: Sat, 9 May 2015 18:32:14 +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: r282679 - head/sys/kern Message-ID: <201505091832.t49IWEhZ047552@svn.freebsd.org>
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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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