From 8a12675186781497bb9de4f28137edbcd6525498 Mon Sep 17 00:00:00 2001
From: pgoyette <pgoyette@NetBSD.org>
Date: Tue, 13 Oct 2015 08:24:35 +0000
Subject: [PATCH] Don't release proc_lock until we're done looking at things
 that are protected by the lock, particularly p_stat and p_waited.  Found by
 Robert Elz.

XXX Pullup to NetBSD-7, -6, -6-0, and -6-1
---
 sys/compat/linux/arch/arm/linux_ptrace.c     | 8 +++++---
 sys/compat/linux/arch/i386/linux_ptrace.c    | 8 +++++---
 sys/compat/linux/arch/powerpc/linux_ptrace.c | 8 +++++---
 3 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/sys/compat/linux/arch/arm/linux_ptrace.c b/sys/compat/linux/arch/arm/linux_ptrace.c
index dbf63857bb63..3c43902903ba 100644
--- a/sys/compat/linux/arch/arm/linux_ptrace.c
+++ b/sys/compat/linux/arch/arm/linux_ptrace.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: linux_ptrace.c,v 1.18 2014/11/09 17:48:07 maxv Exp $	*/
+/*	$NetBSD: linux_ptrace.c,v 1.19 2015/10/13 08:24:35 pgoyette Exp $	*/
 
 /*-
  * Copyright (c) 1999 The NetBSD Foundation, Inc.
@@ -31,7 +31,7 @@
 
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_ptrace.c,v 1.18 2014/11/09 17:48:07 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_ptrace.c,v 1.19 2015/10/13 08:24:35 pgoyette Exp $");
 
 #include <sys/param.h>
 #include <sys/mount.h>
@@ -140,7 +140,6 @@ linux_sys_ptrace_arch(struct lwp *l, const struct linux_sys_ptrace_args *uap,
 		goto out;
 	}
 	mutex_enter(t->p_lock);
-	mutex_exit(proc_lock);
 
 	/*
 	 * You cannot do what you want to the process if:
@@ -148,6 +147,7 @@ linux_sys_ptrace_arch(struct lwp *l, const struct linux_sys_ptrace_args *uap,
 	 */
 	if (!ISSET(t->p_slflag, PSL_TRACED)) {
 		mutex_exit(t->p_lock);
+		mutex_exit(proc_lock);
 		error = EPERM;
 		goto out;
 	}
@@ -160,9 +160,11 @@ linux_sys_ptrace_arch(struct lwp *l, const struct linux_sys_ptrace_args *uap,
 	if (ISSET(t->p_slflag, PSL_FSTRACE) || t->p_pptr != p ||
 	    t->p_stat != SSTOP || !t->p_waited) {
 		mutex_exit(t->p_lock);
+		mutex_exit(proc_lock);
 		error = EBUSY;
 		goto out;
 	}
+	mutex_exit(proc_lock);
 	/* XXX: ptrace needs revamp for multi-threading support. */
 	if (t->p_nlwps > 1) {
 		mutex_exit(t->p_lock);
diff --git a/sys/compat/linux/arch/i386/linux_ptrace.c b/sys/compat/linux/arch/i386/linux_ptrace.c
index 4b8fa0335fc9..99bbdd07ab32 100644
--- a/sys/compat/linux/arch/i386/linux_ptrace.c
+++ b/sys/compat/linux/arch/i386/linux_ptrace.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: linux_ptrace.c,v 1.30 2014/11/09 17:48:07 maxv Exp $	*/
+/*	$NetBSD: linux_ptrace.c,v 1.31 2015/10/13 08:24:35 pgoyette Exp $	*/
 
 /*-
  * Copyright (c) 1999 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_ptrace.c,v 1.30 2014/11/09 17:48:07 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_ptrace.c,v 1.31 2015/10/13 08:24:35 pgoyette Exp $");
 
 #include <sys/param.h>
 #include <sys/mount.h>
@@ -185,7 +185,6 @@ linux_sys_ptrace_arch(struct lwp *l, const struct linux_sys_ptrace_args *uap,
 		goto out;
 	}
 	mutex_enter(t->p_lock);
-	mutex_exit(proc_lock);
 
 	/*
 	 * You cannot do what you want to the process if:
@@ -193,6 +192,7 @@ linux_sys_ptrace_arch(struct lwp *l, const struct linux_sys_ptrace_args *uap,
 	 */
 	if (!ISSET(t->p_slflag, PSL_TRACED)) {
 		mutex_exit(t->p_lock);
+		mutex_exit(proc_lock);
 		error = EPERM;
 		goto out;
 	}
@@ -205,9 +205,11 @@ linux_sys_ptrace_arch(struct lwp *l, const struct linux_sys_ptrace_args *uap,
 	if (ISSET(t->p_slflag, PSL_FSTRACE) || t->p_pptr != p ||
 	    t->p_stat != SSTOP || !t->p_waited) {
 		mutex_exit(t->p_lock);
+		mutex_exit(proc_lock);
 		error = EBUSY;
 		goto out;
 	}
+	mutex_exit(proc_lock);
 	/* XXX: ptrace needs revamp for multi-threading support. */
 	if (t->p_nlwps > 1) {
 		mutex_exit(t->p_lock);
diff --git a/sys/compat/linux/arch/powerpc/linux_ptrace.c b/sys/compat/linux/arch/powerpc/linux_ptrace.c
index 3cb0aa94c3fb..0aef6f77051e 100644
--- a/sys/compat/linux/arch/powerpc/linux_ptrace.c
+++ b/sys/compat/linux/arch/powerpc/linux_ptrace.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: linux_ptrace.c,v 1.28 2014/11/09 17:48:08 maxv Exp $ */
+/*	$NetBSD: linux_ptrace.c,v 1.29 2015/10/13 08:24:35 pgoyette Exp $ */
 
 /*-
  * Copyright (c) 1999, 2001 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_ptrace.c,v 1.28 2014/11/09 17:48:08 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_ptrace.c,v 1.29 2015/10/13 08:24:35 pgoyette Exp $");
 
 #include <sys/param.h>
 #include <sys/mount.h>
@@ -162,7 +162,6 @@ linux_sys_ptrace_arch(struct lwp *l, const struct linux_sys_ptrace_args *uap,
 		goto out;
 	}
 	mutex_enter(t->p_lock);
-	mutex_exit(proc_lock);
 
 	/*
 	 * You cannot do what you want to the process if:
@@ -170,6 +169,7 @@ linux_sys_ptrace_arch(struct lwp *l, const struct linux_sys_ptrace_args *uap,
 	 */
 	if (!ISSET(t->p_slflag, PSL_TRACED)) {
 		mutex_exit(t->p_lock);
+		mutex_exit(proc_lock);
 		error = EPERM;
 		goto out;
 	}
@@ -182,9 +182,11 @@ linux_sys_ptrace_arch(struct lwp *l, const struct linux_sys_ptrace_args *uap,
 	if (ISSET(t->p_slflag, PSL_FSTRACE) || t->p_pptr != p ||
 	    t->p_stat != SSTOP || !t->p_waited) {
 		mutex_exit(t->p_lock);
+		mutex_exit(proc_lock);
 		error = EBUSY;
 		goto out;
 	}
+	mutex_exit(proc_lock);
 	/* XXX: ptrace needs revamp for multi-threading support. */
 	if (t->p_nlwps > 1) {
 		mutex_exit(t->p_lock);