svn commit: r215664 - in head/sys: compat/linux kern

Alexander Leidinger netchild at FreeBSD.org
Mon Nov 22 09:07:00 UTC 2010


Author: netchild
Date: Mon Nov 22 09:06:59 2010
New Revision: 215664
URL: http://svn.freebsd.org/changeset/base/215664

Log:
  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 at stadtbuch.de>, gk
  Reviewed by:	rdivacky (in april 2010)
  MFC after:	5 days

Modified:
  head/sys/compat/linux/linux_emul.c
  head/sys/compat/linux/linux_emul.h
  head/sys/compat/linux/linux_misc.c
  head/sys/kern/kern_exit.c

Modified: head/sys/compat/linux/linux_emul.c
==============================================================================
--- head/sys/compat/linux/linux_emul.c	Mon Nov 22 09:04:29 2010	(r215663)
+++ head/sys/compat/linux/linux_emul.c	Mon Nov 22 09:06:59 2010	(r215664)
@@ -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, stru
 	}
 
 	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, stru
 	} 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, stru
 	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,
 	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);
+}

Modified: head/sys/compat/linux/linux_emul.h
==============================================================================
--- head/sys/compat/linux/linux_emul.h	Mon Nov 22 09:04:29 2010	(r215663)
+++ head/sys/compat/linux/linux_emul.h	Mon Nov 22 09:06:59 2010	(r215664)
@@ -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
 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;

Modified: head/sys/compat/linux/linux_misc.c
==============================================================================
--- head/sys/compat/linux/linux_misc.c	Mon Nov 22 09:04:29 2010	(r215663)
+++ head/sys/compat/linux/linux_misc.c	Mon Nov 22 09:06:59 2010	(r215664)
@@ -1695,34 +1695,23 @@ linux_setdomainname(struct thread *td, s
 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?)

Modified: head/sys/kern/kern_exit.c
==============================================================================
--- head/sys/kern/kern_exit.c	Mon Nov 22 09:04:29 2010	(r215663)
+++ head/sys/kern/kern_exit.c	Mon Nov 22 09:06:59 2010	(r215664)
@@ -200,6 +200,7 @@ exit1(struct thread *td, int rv)
 	while (p->p_lock > 0)
 		msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0);
 
+	p->p_xstat = rv;	/* Let event handler change exit status */
 	PROC_UNLOCK(p);
 	/* Drain the limit callout while we don't have the proc locked */
 	callout_drain(&p->p_limco);
@@ -242,6 +243,7 @@ exit1(struct thread *td, int rv)
 	 * P_PPWAIT is set; we will wakeup the parent below.
 	 */
 	PROC_LOCK(p);
+	rv = p->p_xstat;	/* Event handler could change exit status */
 	stopprofclock(p);
 	p->p_flag &= ~(P_TRACED | P_PPWAIT);
 
@@ -424,7 +426,6 @@ exit1(struct thread *td, int rv)
 
 	/* Save exit status. */
 	PROC_LOCK(p);
-	p->p_xstat = rv;
 	p->p_xthread = td;
 
 	/* Tell the prison that we are gone. */


More information about the svn-src-head mailing list