From 8473ab813103f7b109eb53eea9b7980fb973783f Mon Sep 17 00:00:00 2001
From: Sidong Yang <realwakka@gmail.com>
Date: Sun, 8 Oct 2023 09:17:17 +0000
Subject: [PATCH] btrfs-progs: qgroup: check null when comparing paths

This patch fixes a bug that could occur when comparing paths in showing
qgroups list. Old code doesn't check it and the bug occurs when there is
stale qgroup and its path is null. Check whether it is null and return
without comparing paths.

Issue: #687
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Sidong Yang <realwakka@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
 cmds/qgroup.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/cmds/qgroup.c b/cmds/qgroup.c
index d9104d1a..265c4910 100644
--- a/cmds/qgroup.c
+++ b/cmds/qgroup.c
@@ -486,6 +486,14 @@ static int comp_entry_with_path(struct btrfs_qgroup *entry1,
 	if (ret)
 		goto out;
 
+	if (!p1) {
+		ret = p2 ? 1 : 0;
+		goto out;
+	} else if (!p2) {
+		ret = -1;
+		goto out;
+	}
+
 	while (*p1 && *p2) {
 		if (*p1 != *p2)
 			break;