[patch 2.4.28-rc1] Avoid oops in proc_delete_inode

[Keith Owens <kaos@sgi.com>]

Under heavy load, vmstat, top and other programs that access /proc can
oops.  PROC_INODE_PROPER(inode) is sometimes false for pid entries
(usually zombies), but inode->u.generic_ip is not NULL.

Backport a fix by AL Viro from 2.5.7-pre2 to 2.4.28-rc1.

Signed-off-by: Keith Owens <kaos@sgi.com>

Index: 2.4.28-rc1/fs/proc/base.c
===================================================================
--- 2.4.28-rc1.orig/fs/proc/base.c	2004-08-08 10:10:49.000000000 +1000
+++ 2.4.28-rc1/fs/proc/base.c	2004-11-04 13:25:16.402602459 +1100
@@ -780,6 +780,7 @@ out:
 	return inode;
 
 out_unlock:
+	node->u.generic_ip = NULL;
 	iput(inode);
 	return NULL;
 }