linux-kernel - [PATCH -next] ubifs: ubifs_gc_start_commit: Fix error check for lp pointer

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Date:   Wed, 23 Jun 2021 09:21:46 +0800
From:   Zhihao Cheng <chengzhihao1@...wei.com>
To:     <richard@....at>
CC:     <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <dan.carpenter@...cle.com>, <chengzhihao1@...wei.com>,
        <yukuai3@...wei.com>
Subject: [PATCH -next] ubifs: ubifs_gc_start_commit: Fix error check for lp pointer

Treating the NULL pointer returned from ubifs_fast_find_frdi_idx() as
ENOMEM will make ubifs_gc_start_commit() fails, which could make ubifs
read-only. Actually a returned NULL pointer is the termination
condition in while-loop in ubifs_gc_start_commit().

Fixes: c770cd5190ba ("ubifs: fix an IS_ERR() vs NULL check")
Reported-by: Colin Ian King <colin.king@...onical.com>
Signed-off-by: Zhihao Cheng <chengzhihao1@...wei.com>
---
 fs/ubifs/gc.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/fs/ubifs/gc.c b/fs/ubifs/gc.c
index 7cc22d7317ea..b1f276599b04 100644
--- a/fs/ubifs/gc.c
+++ b/fs/ubifs/gc.c
@@ -895,10 +895,6 @@ int ubifs_gc_start_commit(struct ubifs_info *c)
 	/* Record index freeable LEBs for unmapping after commit */
 	while (1) {
 		lp = ubifs_fast_find_frdi_idx(c);
-		if (!lp) {
-			err = -ENOMEM;
-			goto out;
-		}
 		if (!lp)
 			break;
 		idx_gc = kmalloc(sizeof(struct ubifs_gced_idx_leb), GFP_NOFS);
-- 
2.31.1