svn commit: r192151 - head/sys/fs/devfs

[Konstantin Belousov]

Author: kib
Date: Fri May 15 19:23:05 2009
New Revision: 192151
URL: http://svn.freebsd.org/changeset/base/192151

Log:
  Devfs replaces file ops vector with devfs-specific one in devfs_open(),
  before the struct file is fully initialized in vn_open(), in particular,
  fp->f_vnode is NULL. Other thread calling file operation before f_vnode
  is set results in NULL pointer dereference in devvn_refthread().
  
  Initialize f_vnode before calling d_fdopen() cdevsw method, that might
  set file ops too.
  
  Reported and tested by:	Chris Timmons <cwt networks cwu edu>
  	(RELENG_7 version)
  MFC after:	3 days

Modified:
  head/sys/fs/devfs/devfs_vnops.c

Modified: head/sys/fs/devfs/devfs_vnops.c
==============================================================================
--- head/sys/fs/devfs/devfs_vnops.c	Fri May 15 19:19:27 2009	(r192150)
+++ head/sys/fs/devfs/devfs_vnops.c	Fri May 15 19:23:05 2009	(r192151)
@@ -942,8 +942,10 @@ devfs_open(struct vop_open_args *ap)
 
 	fpop = td->td_fpop;
 	td->td_fpop = fp;
-	if (fp != NULL)
+	if (fp != NULL) {
 		fp->f_data = dev;
+		fp->f_vnode = vp;
+	}
 	if (dsw->d_fdopen != NULL)
 		error = dsw->d_fdopen(dev, ap->a_mode, td, fp);
 	else