Fix for the panic("vm_thread_new: kstack allocation failed") and

silent NULL pointer dereference in the i386 and sparc64 pmap_pinit()
when the kmem_alloc_nofault() failed to allocate address space. Both
functions now return error instead of panicing or dereferencing NULL.

As consequence, vmspace_exec() and vmspace_unshare() returns the errno
int. struct vmspace arg was added to vm_forkproc() to avoid dealing
with failed allocation when most of the fork1() job is already done.

The kernel stack for the thread is now set up in the thread_alloc(),
that itself may return NULL. Also, allocation of the first process
thread is performed in the fork1() to properly deal with stack
allocation failure. proc_linkup() is separated into proc_linkup()
called from fork1(), and proc_linkup0(), that is used to set up the
kernel process (was known as swapper).

In collaboration with:	Peter Holm
Reviewed by:	jhb

3 files changed, 4 insertions, 3 deletions

diff --git a/sys/powerpc/aim/machdep.c b/sys/powerpc/aim/machdep.c
index 98c4051..0d771e1 100644
--- a/sys/powerpc/aim/machdep.c
+++ b/sys/powerpc/aim/machdep.c
@@ -287,7 +287,7 @@ powerpc_init(u_int startkernel, u_int endkernel, u_int basekernel, void *mdp)
 	/*
 	 * Start initializing proc0 and thread0.
 	 */
-	proc_linkup(&proc0, &thread0);
+	proc_linkup0(&proc0, &thread0);
 	thread0.td_frame = &frame0;
 
 	/*
diff --git a/sys/powerpc/powerpc/machdep.c b/sys/powerpc/powerpc/machdep.c
index 98c4051..0d771e1 100644
--- a/sys/powerpc/powerpc/machdep.c
+++ b/sys/powerpc/powerpc/machdep.c
@@ -287,7 +287,7 @@ powerpc_init(u_int startkernel, u_int endkernel, u_int basekernel, void *mdp)
 	/*
 	 * Start initializing proc0 and thread0.
 	 */
-	proc_linkup(&proc0, &thread0);
+	proc_linkup0(&proc0, &thread0);
 	thread0.td_frame = &frame0;
 
 	/*
diff --git a/sys/powerpc/powerpc/pmap_dispatch.c b/sys/powerpc/powerpc/pmap_dispatch.c
index 92ac514..9a9c1f5 100644
--- a/sys/powerpc/powerpc/pmap_dispatch.c
+++ b/sys/powerpc/powerpc/pmap_dispatch.c
@@ -193,10 +193,11 @@ pmap_page_init(vm_page_t m)
 	MMU_PAGE_INIT(mmu_obj, m);
 }
 
-void
+int
 pmap_pinit(pmap_t pmap)
 {
 	MMU_PINIT(mmu_obj, pmap);
+	return (1);
 }
 
 void