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

1 files changed, 3 insertions, 1 deletions

diff --git a/sys/i386/ibcs2/imgact_coff.c b/sys/i386/ibcs2/imgact_coff.c
index b078e5654972..74a01f4c4a9c 100644
--- a/sys/i386/ibcs2/imgact_coff.c
+++ b/sys/i386/ibcs2/imgact_coff.c
@@ -337,7 +337,9 @@ exec_coff_imgact(imgp)
 
 	VOP_UNLOCK(imgp->vp, 0, td);
 
-	exec_new_vmspace(imgp, &ibcs2_svr3_sysvec);
+	error = exec_new_vmspace(imgp, &ibcs2_svr3_sysvec);
+	if (error)
+		goto fail;
 	vmspace = imgp->proc->p_vmspace;
 
 	for (i = 0; i < nscns; i++) {