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, 5 insertions, 5 deletions

diff --git a/sys/vm/vm_extern.h b/sys/vm/vm_extern.h
index 31f6e2354eba..27580bd99149 100644
--- a/sys/vm/vm_extern.h
+++ b/sys/vm/vm_extern.h
@@ -70,14 +70,14 @@ int vm_fault(vm_map_t, vm_offset_t, vm_prot_t, int);
 void vm_fault_copy_entry(vm_map_t, vm_map_t, vm_map_entry_t, vm_map_entry_t);
 void vm_fault_unwire(vm_map_t, vm_offset_t, vm_offset_t, boolean_t);
 int vm_fault_wire(vm_map_t, vm_offset_t, vm_offset_t, boolean_t, boolean_t);
-void vm_forkproc(struct thread *, struct proc *, struct thread *, int);
+int vm_forkproc(struct thread *, struct proc *, struct thread *, struct vmspace *, int);
 void vm_waitproc(struct proc *);
 int vm_mmap(vm_map_t, vm_offset_t *, vm_size_t, vm_prot_t, vm_prot_t, int, objtype_t, void *, vm_ooffset_t);
 void vm_set_page_size(void);
 struct vmspace *vmspace_alloc(vm_offset_t, vm_offset_t);
 struct vmspace *vmspace_fork(struct vmspace *);
-void vmspace_exec(struct proc *, vm_offset_t, vm_offset_t);
-void vmspace_unshare(struct proc *);
+int vmspace_exec(struct proc *, vm_offset_t, vm_offset_t);
+int vmspace_unshare(struct proc *);
 void vmspace_exit(struct thread *);
 struct vmspace *vmspace_acquire_ref(struct proc *);
 void vmspace_free(struct vmspace *);
@@ -92,8 +92,8 @@ struct sf_buf *vm_imgact_map_page(vm_object_t object, vm_ooffset_t offset);
 void vm_imgact_unmap_page(struct sf_buf *sf);
 void vm_thread_dispose(struct thread *td);
 void vm_thread_dispose_altkstack(struct thread *td);
-void vm_thread_new(struct thread *td, int pages);
-void vm_thread_new_altkstack(struct thread *td, int pages);
+int vm_thread_new(struct thread *td, int pages);
+int vm_thread_new_altkstack(struct thread *td, int pages);
 void vm_thread_swapin(struct thread *td);
 void vm_thread_swapout(struct thread *td);
 #endif				/* _KERNEL */