From: Bob Peterson rpeterso@redhat.com
commit 778721510e84209f78e31e2ccb296ae36d623f5e upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/gfs2/rgrp.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/fs/gfs2/rgrp.c +++ b/fs/gfs2/rgrp.c @@ -1017,6 +1017,10 @@ static int gfs2_ri_update(struct gfs2_in 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;