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Date:      Fri, 23 May 2014 09:29:05 +0000 (UTC)
From:      Konstantin Belousov <kib@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org
Subject:   svn commit: r266582 - in stable/10/sys: kern sys vm
Message-ID:  <201405230929.s4N9T5UN033850@svn.freebsd.org>
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Author: kib
Date: Fri May 23 09:29:04 2014
New Revision: 266582
URL: http://svnweb.freebsd.org/changeset/base/266582

Log:
  MFC r266464:
  In execve(2), postpone the free of old vmspace until the threads are resumed
  and exited.

Modified:
  stable/10/sys/kern/kern_exec.c
  stable/10/sys/sys/proc.h
  stable/10/sys/vm/vm_map.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/kern/kern_exec.c
==============================================================================
--- stable/10/sys/kern/kern_exec.c	Fri May 23 08:46:28 2014	(r266581)
+++ stable/10/sys/kern/kern_exec.c	Fri May 23 09:29:04 2014	(r266582)
@@ -283,6 +283,7 @@ kern_execve(td, args, mac_p)
 	struct mac *mac_p;
 {
 	struct proc *p = td->td_proc;
+	struct vmspace *oldvmspace;
 	int error;
 
 	AUDIT_ARG_ARGV(args->begin_argv, args->argc,
@@ -299,6 +300,8 @@ kern_execve(td, args, mac_p)
 		PROC_UNLOCK(p);
 	}
 
+	KASSERT((td->td_pflags & TDP_EXECVMSPC) == 0, ("nested execve"));
+	oldvmspace = td->td_proc->p_vmspace;
 	error = do_execve(td, args, mac_p);
 
 	if (p->p_flag & P_HADTHREADS) {
@@ -313,6 +316,12 @@ kern_execve(td, args, mac_p)
 			thread_single_end();
 		PROC_UNLOCK(p);
 	}
+	if ((td->td_pflags & TDP_EXECVMSPC) != 0) {
+		KASSERT(td->td_proc->p_vmspace != oldvmspace,
+		    ("oldvmspace still used"));
+		vmspace_free(oldvmspace);
+		td->td_pflags &= ~TDP_EXECVMSPC;
+	}
 
 	return (error);
 }

Modified: stable/10/sys/sys/proc.h
==============================================================================
--- stable/10/sys/sys/proc.h	Fri May 23 08:46:28 2014	(r266581)
+++ stable/10/sys/sys/proc.h	Fri May 23 09:29:04 2014	(r266582)
@@ -425,6 +425,7 @@ do {									\
 #define	TDP_NERRNO	0x08000000 /* Last errno is already in td_errno */
 #define	TDP_UIOHELD	0x10000000 /* Current uio has pages held in td_ma */
 #define	TDP_DEVMEMIO	0x20000000 /* Accessing memory for /dev/mem */
+#define	TDP_EXECVMSPC	0x40000000 /* Execve destroyed old vmspace */
 
 /*
  * Reasons that the current thread can not be run yet.

Modified: stable/10/sys/vm/vm_map.c
==============================================================================
--- stable/10/sys/vm/vm_map.c	Fri May 23 08:46:28 2014	(r266581)
+++ stable/10/sys/vm/vm_map.c	Fri May 23 09:29:04 2014	(r266582)
@@ -3751,6 +3751,8 @@ vmspace_exec(struct proc *p, vm_offset_t
 	struct vmspace *oldvmspace = p->p_vmspace;
 	struct vmspace *newvmspace;
 
+	KASSERT((curthread->td_pflags & TDP_EXECVMSPC) == 0,
+	    ("vmspace_exec recursed"));
 	newvmspace = vmspace_alloc(minuser, maxuser, NULL);
 	if (newvmspace == NULL)
 		return (ENOMEM);
@@ -3767,7 +3769,7 @@ vmspace_exec(struct proc *p, vm_offset_t
 	PROC_VMSPACE_UNLOCK(p);
 	if (p == curthread->td_proc)
 		pmap_activate(curthread);
-	vmspace_free(oldvmspace);
+	curthread->td_pflags |= TDP_EXECVMSPC;
 	return (0);
 }

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