From: Steve Dickson <SteveD@redhat.com>
Subject: [RHEL5.1] [PATCH] NFSd oops when exporting krb5p mount
Date: Thu, 05 Jul 2007 12:03:21 -0400
Bugzilla: 247120
Message-Id: <468D1649.7040602@RedHat.com>
Changelog: [nfs] NFSd oops when exporting krb5p mount


I found this oops while doing some unit testing on
a (fairly) recent RHEL5 kernel (2.6.18-30.el5xen).

Exporting Kerberos enabled exports would cause the server
to oops when the exports were unexported. Its not clear
why, but this happen every time on xen clients but never
on non-xen machines.

The details are in the bx:
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=247120

<unneeded and probably inappropriate sarcasm>
I know the 3-ack process does not allow for such adhoc
testing and asking for this to be in 5.1 do put be in
the *5-ack* range (if one includes exception and blocker acks), but
</unneeded and probably inappropriate sarcasm>
I do strongly suggest we get this into 5.1 since it was
so reproduce able on my xen client.

Please ack.

steved.

commit f988443a84528bd30c2f474efa5e2c511959f19b
Author: NeilBrown <neilb@suse.de>

    [PATCH] knfsd: Fix up some bit-rot in exp_export
    
    The nfsservctl system call isn't used but recent nfs-utils releases for
    exporting filesystems, and consequently the code that is uses - exp_export -
    has suffered some bitrot.
    
    Particular:
      - some newly added fields in 'struct svc_export' are being initialised
        properly.
      - the return value is now always -ENOMEM ...
    
    This patch fixes both these problems.
    
    Signed-off-by: Neil Brown <neilb@suse.de>
    Signed-off-by: Andrew Morton <akpm@osdl.org>
    Signed-off-by: Linus Torvalds <torvalds@osdl.org>

--- linux-2.6.18.i686/fs/nfsd/export.c.orig	2007-07-05 10:28:55.000000000 -0400
+++ linux-2.6.18.i686/fs/nfsd/export.c	2007-07-05 10:29:58.000000000 -0400
@@ -950,6 +950,8 @@ exp_export(struct nfsctl_export *nxp)
 
 	exp = exp_get_by_name(clp, nd.mnt, nd.dentry, NULL);
 
+	memset(&new, 0, sizeof(new));
+
 	/* must make sure there won't be an ex_fsid clash */
 	if ((nxp->ex_flags & NFSEXP_FSID) &&
 	    (fsid_key = exp_get_fsid_key(clp, nxp->ex_dev)) &&
@@ -980,6 +982,9 @@ exp_export(struct nfsctl_export *nxp)
 
 	new.h.expiry_time = NEVER;
 	new.h.flags = 0;
+	new.ex_path = kstrdup(nxp->ex_path, GFP_KERNEL);
+	if (!new.ex_path)
+		goto finish;
 	new.ex_client = clp;
 	new.ex_mnt = nd.mnt;
 	new.ex_dentry = nd.dentry;
@@ -1000,10 +1005,11 @@ exp_export(struct nfsctl_export *nxp)
 		/* failed to create at least one index */
 		exp_do_unexport(exp);
 		cache_flush();
-		err = -ENOMEM;
-	}
-
+	} else
+		err = 0;
 finish:
+	if (new.ex_path)
+		kfree(new.ex_path);
 	if (exp)
 		exp_put(exp);
 	if (fsid_key && !IS_ERR(fsid_key))