From 778721510e84209f78e31e2ccb296ae36d623f5e Mon Sep 17 00:00:00 2001
From: Bob Peterson <rpeterso@redhat.com>
Date: Tue, 24 Nov 2020 10:44:36 -0500
Subject: [PATCH] gfs2: check for empty rgrp tree in gfs2_ri_update
Git-commit: 778721510e84209f78e31e2ccb296ae36d623f5e
Patch-mainline: v5.10-rc7
References: git-fixes
If gfs2 tries to mount a (corrupt) file system that has no resource
groups it still tries to set preferences on the first one, which causes
a kernel null pointer dereference. This patch adds a check to function
gfs2_ri_update so this condition is detected and reported back as an
error.
Reported-by: syzbot+e3f23ce40269a4c9053a@syzkaller.appspotmail.com
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Acked-by: Anthony Iliopoulos <ailiop@suse.com>
---
fs/gfs2/rgrp.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index f7addc6197ed..5e8eef9990e3 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -985,6 +985,10 @@ static int gfs2_ri_update(struct gfs2_inode *ip)
if (error < 0)
return error;
+ if (RB_EMPTY_ROOT(&sdp->sd_rindex_tree)) {
+ fs_err(sdp, "no resource groups found in the file system.\n");
+ return -ENOENT;
+ }
set_rgrp_preferences(sdp);
sdp->sd_rindex_uptodate = 1;
--
2.43.0