NFS: Fix a tracepoint NULL-pointer dereference

amschuma-ntap · trondmypd · commit 39d0d3bdf7ba · 2015-10-06T18:56:25.000-04:00
Running xfstest generic/013 with the tracepoint nfs:nfs4_open_file
enabled produces a NULL-pointer dereference when calculating fileid and
filehandle of the opened file.  Fix this by checking if state is NULL
before trying to use the inode pointer.

Reported-by: Olga Kornievskaia &lt;aglo@umich.edu&gt;
Signed-off-by: Anna Schumaker &lt;Anna.Schumaker@Netapp.com&gt;
Signed-off-by: Trond Myklebust &lt;trond.myklebust@primarydata.com&gt;
diff --git a/fs/nfs/nfs4trace.h b/fs/nfs/nfs4trace.h
@@ -409,7 +409,7 @@ DECLARE_EVENT_CLASS(nfs4_open_event,
 			__entry->flags = flags;
 			__entry->fmode = (__force unsigned int)ctx->mode;
 			__entry->dev = ctx->dentry->d_sb->s_dev;
-			if (!IS_ERR(state))
+			if (!IS_ERR_OR_NULL(state))
 				inode = state->inode;
 			if (inode != NULL) {
 				__entry->fileid = NFS_FILEID(inode);
