svn commit: r197855 - in stable/8/sys: . amd64/include/xen cddl/contrib/opensolaris contrib/dev/acpica contrib/pf dev/xen/xenpci kern

[Konstantin Belousov]

Author: kib
Date: Thu Oct  8 11:28:32 2009
New Revision: 197855
URL: http://svn.freebsd.org/changeset/base/197855

Log:
  MFC r197662:
  Do not dereference vp->v_mount without holding vnode lock and checking
  that the vnode is not reclaimed.
  
  Approved by:	re (bz)

Modified:
  stable/8/sys/   (props changed)
  stable/8/sys/amd64/include/xen/   (props changed)
  stable/8/sys/cddl/contrib/opensolaris/   (props changed)
  stable/8/sys/contrib/dev/acpica/   (props changed)
  stable/8/sys/contrib/pf/   (props changed)
  stable/8/sys/dev/xen/xenpci/   (props changed)
  stable/8/sys/kern/uipc_syscalls.c

Modified: stable/8/sys/kern/uipc_syscalls.c
==============================================================================
--- stable/8/sys/kern/uipc_syscalls.c	Thu Oct  8 11:07:15 2009	(r197854)
+++ stable/8/sys/kern/uipc_syscalls.c	Thu Oct  8 11:28:32 2009	(r197855)
@@ -2085,9 +2085,11 @@ retry_space:
 				/*
 				 * Get the page from backing store.
 				 */
-				bsize = vp->v_mount->mnt_stat.f_iosize;
 				vfslocked = VFS_LOCK_GIANT(vp->v_mount);
-				vn_lock(vp, LK_SHARED | LK_RETRY);
+				error = vn_lock(vp, LK_SHARED);
+				if (error != 0)
+					goto after_read;
+				bsize = vp->v_mount->mnt_stat.f_iosize;
 
 				/*
 				 * XXXMAC: Because we don't have fp->f_cred
@@ -2100,6 +2102,7 @@ retry_space:
 				    IO_VMIO | ((MAXBSIZE / bsize) << IO_SEQSHIFT),
 				    td->td_ucred, NOCRED, &resid, td);
 				VOP_UNLOCK(vp, 0);
+			after_read:
 				VFS_UNLOCK_GIANT(vfslocked);
 				VM_OBJECT_LOCK(obj);
 				vm_page_io_finish(pg);