Module Name: src
Committed By: riz
Date: Sat Mar 10 16:49:01 UTC 2012
Modified Files:
src/sys/kern [netbsd-6]: kern_exec.c
Log Message:
Pull up following revision(s) (requested by martin in ticket #107):
sys/kern/kern_exec.c: revision 1.345
sys/kern/kern_exec.c: revision 1.346
Make sure the child of a posix_spawn operation is not preempted during
the times when it does not have any vm_space.
Should fix PR kern/46153.
Remove a KPREEMPT_ENABLE() in an error path I overlooked in the previous
change - pointed out by Manuel Bouyer.
While there, add a KASSERT() to make sure we have preemption enabled in
the success case.
To generate a diff of this commit:
cvs rdiff -u -r1.339.2.2 -r1.339.2.3 src/sys/kern/kern_exec.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/kern_exec.c
diff -u src/sys/kern/kern_exec.c:1.339.2.2 src/sys/kern/kern_exec.c:1.339.2.3
--- src/sys/kern/kern_exec.c:1.339.2.2 Wed Feb 22 18:43:35 2012
+++ src/sys/kern/kern_exec.c Sat Mar 10 16:49:01 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_exec.c,v 1.339.2.2 2012/02/22 18:43:35 riz Exp $ */
+/* $NetBSD: kern_exec.c,v 1.339.2.3 2012/03/10 16:49:01 riz Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -59,7 +59,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.339.2.2 2012/02/22 18:43:35 riz Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.339.2.3 2012/03/10 16:49:01 riz Exp $");
#include "opt_exec.h"
#include "opt_ktrace.h"
@@ -1778,11 +1778,13 @@ spawn_return(void *arg)
register_t retval;
bool have_reflock;
+ /* we have been created non-preemptable */
+ KASSERT(l->l_nopreempt == 1);
+
/*
* The following actions may block, so we need a temporary
* vmspace - borrow the kernel one
*/
- KPREEMPT_DISABLE(l);
l->l_proc->p_vmspace = proc0.p_vmspace;
pmap_activate(l);
KPREEMPT_ENABLE(l);
@@ -1908,8 +1910,6 @@ spawn_return(void *arg)
KPREEMPT_DISABLE(l);
pmap_deactivate(l);
l->l_proc->p_vmspace = NULL;
- KPREEMPT_ENABLE(l);
-
/* now do the real exec */
rw_enter(&exec_lock, RW_READER);
@@ -1920,6 +1920,10 @@ spawn_return(void *arg)
else if (error)
goto report_error;
+ /* we now have our own vmspace */
+ KPREEMPT_ENABLE(l);
+ KASSERT(l->l_nopreempt == 0);
+
/* done, signal parent */
mutex_enter(&spawn_data->sed_mtx_child);
cv_signal(&spawn_data->sed_cv_child_ready);
@@ -1940,7 +1944,7 @@ spawn_return(void *arg)
KPREEMPT_DISABLE(l);
pmap_deactivate(l);
l->l_proc->p_vmspace = NULL;
- KPREEMPT_ENABLE(l);
+ /* do not enable preemption without vmspace */
}
/*
@@ -2269,6 +2273,8 @@ sys_posix_spawn(struct lwp *l1, const st
kauth_cred_free(ocred);
}
+ l2->l_nopreempt = 1; /* start it non-preemptable */
+
/*
* It's now safe for the scheduler and other processes to see the
* child process.
