From: Chao Yu <yuchao0@huawei.com>
Date: Thu, 26 Mar 2020 09:42:26 +0000 (+0800)
Subject: f2fs: fix to verify tpage before releasing in f2fs_free_dic()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=8908e753109fd7abb4949a3d6118a9a5e3766ea0;p=linux.git

f2fs: fix to verify tpage before releasing in f2fs_free_dic()

In below error path, tpages[i] could be NULL, fix to check it before
releasing it.
- f2fs_read_multi_pages
 - f2fs_alloc_dic
  - f2fs_free_dic

Fixes: 61fbae2b2b12 ("f2fs: fix to avoid NULL pointer dereference")
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index ca4f54fbbd2e9..df7b2d15eacde 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -1333,6 +1333,8 @@ void f2fs_free_dic(struct decompress_io_ctx *dic)
 		for (i = 0; i < dic->cluster_size; i++) {
 			if (dic->rpages[i])
 				continue;
+			if (!dic->tpages[i])
+				continue;
 			unlock_page(dic->tpages[i]);
 			put_page(dic->tpages[i]);
 		}