By using the 32-bit Linux version of Sun's Java Development Kit 1.6

on FreeBSD (amd64), invocations of "javac" (or "java") eventually
end with the output of "Killed" and exit code 137.

This is caused by:
1. After calling exec() in multithreaded linux program threads are not
   destroyed and continue running. They get killed after program being
   executed finishes.

2. linux_exit_group doesn't return correct exit code when called not
   from group leader. Which happens regularly using sun jvm.

The submitters fix this in a similar way to how NetBSD handles this.

I took the PRs away from dchagin, who seems to be out of touch of
this since a while (no response from him).

The patches committed here are from [2], with some little modifications
from me to the style.

PR:		141439 [1], 144194 [2]
Submitted by:	Stefan Schmidt <stefan.schmidt@stadtbuch.de>, gk
Reviewed by:	rdivacky (in april 2010)
MFC after:	5 days

3 files changed, 53 insertions, 22 deletions

diff --git a/sys/compat/linux/linux_emul.c b/sys/compat/linux/linux_emul.c
index dc81553..eb10ca6 100644
--- a/sys/compat/linux/linux_emul.c
+++ b/sys/compat/linux/linux_emul.c
@@ -155,7 +155,7 @@ void
 linux_proc_exit(void *arg __unused, struct proc *p)
 {
 	struct linux_emuldata *em;
-	int error;
+	int error, shared_flags, shared_xstat;
 	struct thread *td = FIRST_THREAD_IN_PROC(p);
 	int *child_clear_tid;
 	struct proc *q, *nq;
@@ -187,6 +187,8 @@ linux_proc_exit(void *arg __unused, struct proc *p)
 	}
 
 	EMUL_SHARED_WLOCK(&emul_shared_lock);
+	shared_flags = em->shared->flags;
+	shared_xstat = em->shared->xstat;
 	LIST_REMOVE(em, threads);
 
 	em->shared->refs--;
@@ -196,6 +198,12 @@ linux_proc_exit(void *arg __unused, struct proc *p)
 	} else	
 		EMUL_SHARED_WUNLOCK(&emul_shared_lock);
 
+	if ((shared_flags & EMUL_SHARED_HASXSTAT) != 0) {
+		PROC_LOCK(p);
+		p->p_xstat = shared_xstat;
+		PROC_UNLOCK(p);
+	}
+
 	if (child_clear_tid != NULL) {
 		struct linux_sys_futex_args cup;
 		int null = 0;
@@ -257,6 +265,9 @@ linux_proc_exec(void *arg __unused, struct proc *p, struct image_params *imgp)
 	if (__predict_false(imgp->sysent == &elf_linux_sysvec
 	    && p->p_sysent != &elf_linux_sysvec))
 		linux_proc_init(FIRST_THREAD_IN_PROC(p), p->p_pid, 0);
+	if (__predict_false(p->p_sysent == &elf_linux_sysvec))
+		/* Kill threads regardless of imgp->sysent value */
+		linux_kill_threads(FIRST_THREAD_IN_PROC(p), SIGKILL);
 	if (__predict_false(imgp->sysent != &elf_linux_sysvec
 	    && p->p_sysent == &elf_linux_sysvec)) {
 		struct linux_emuldata *em;
@@ -334,3 +345,29 @@ linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args
 	EMUL_UNLOCK(&emul_lock);
 	return 0;
 }
+
+void
+linux_kill_threads(struct thread *td, int sig)
+{
+	struct linux_emuldata *em, *td_em, *tmp_em;
+	struct proc *sp;
+
+	td_em = em_find(td->td_proc, EMUL_DONTLOCK);
+
+	KASSERT(td_em != NULL, ("linux_kill_threads: emuldata not found.\n"));
+
+	EMUL_SHARED_RLOCK(&emul_shared_lock);
+	LIST_FOREACH_SAFE(em, &td_em->shared->threads, threads, tmp_em) {
+		if (em->pid == td_em->pid)
+			continue;
+
+		sp = pfind(em->pid);
+		if ((sp->p_flag & P_WEXIT) == 0)
+			psignal(sp, sig);
+		PROC_UNLOCK(sp);
+#ifdef DEBUG
+		printf(LMSG("linux_kill_threads: kill PID %d\n"), em->pid);
+#endif
+	}
+	EMUL_SHARED_RUNLOCK(&emul_shared_lock);
+}
diff --git a/sys/compat/linux/linux_emul.h b/sys/compat/linux/linux_emul.h
index 8ce27d7..43034ff 100644
--- a/sys/compat/linux/linux_emul.h
+++ b/sys/compat/linux/linux_emul.h
@@ -31,8 +31,12 @@
 #ifndef _LINUX_EMUL_H_
 #define	_LINUX_EMUL_H_
 
+#define EMUL_SHARED_HASXSTAT	0x01
+
 struct linux_emuldata_shared {
 	int	refs;
+	int	flags;
+	int	xstat;
 	pid_t	group_pid;
 
 	LIST_HEAD(, linux_emuldata) threads; /* head of list of linux threads */
@@ -76,6 +80,7 @@ int	linux_proc_init(struct thread *, pid_t, int);
 void	linux_proc_exit(void *, struct proc *);
 void	linux_schedtail(void *, struct proc *);
 void	linux_proc_exec(void *, struct proc *, struct image_params *);
+void	linux_kill_threads(struct thread *, int);
 
 extern struct sx	emul_shared_lock;
 extern struct mtx	emul_lock;
diff --git a/sys/compat/linux/linux_misc.c b/sys/compat/linux/linux_misc.c
index d2cf6b6..c50bf1c 100644
--- a/sys/compat/linux/linux_misc.c
+++ b/sys/compat/linux/linux_misc.c
@@ -1695,34 +1695,23 @@ linux_setdomainname(struct thread *td, struct linux_setdomainname_args *args)
 int
 linux_exit_group(struct thread *td, struct linux_exit_group_args *args)
 {
-	struct linux_emuldata *em, *td_em, *tmp_em;
-	struct proc *sp;
+	struct linux_emuldata *em;
 
 #ifdef DEBUG
 	if (ldebug(exit_group))
 		printf(ARGS(exit_group, "%i"), args->error_code);
 #endif
 
-	if (linux_use26(td)) {
-		td_em = em_find(td->td_proc, EMUL_DONTLOCK);
-
-		KASSERT(td_em != NULL, ("exit_group: emuldata not found.\n"));
-
-		EMUL_SHARED_RLOCK(&emul_shared_lock);
-		LIST_FOREACH_SAFE(em, &td_em->shared->threads, threads, tmp_em) {
-			if (em->pid == td_em->pid)
-				continue;
-
-			sp = pfind(em->pid);
-			psignal(sp, SIGKILL);
-			PROC_UNLOCK(sp);
-#ifdef DEBUG
-			printf(LMSG("linux_sys_exit_group: kill PID %d\n"), em->pid);
-#endif
-		}
-
-		EMUL_SHARED_RUNLOCK(&emul_shared_lock);
+	em = em_find(td->td_proc, EMUL_DONTLOCK);
+	if (em->shared->refs > 1) {
+		EMUL_SHARED_WLOCK(&emul_shared_lock);
+		em->shared->flags |= EMUL_SHARED_HASXSTAT;
+		em->shared->xstat = W_EXITCODE(args->error_code, 0);
+		EMUL_SHARED_WUNLOCK(&emul_shared_lock);
+		if (linux_use26(td))
+			linux_kill_threads(td, SIGKILL);
 	}
+
 	/*
 	 * XXX: we should send a signal to the parent if
 	 * SIGNAL_EXIT_GROUP is set. We ignore that (temporarily?)