From 956510c0c7439e90b8103aaeaf4da92878c622f0 Mon Sep 17 00:00:00 2001
From: Alexander Potapenko <glider@google.com>
Date: Mon, 21 Nov 2022 12:21:30 +0100
Subject: [PATCH] fs: ext4: initialize fsdata in pagecache_write()
Git-commit: 956510c0c7439e90b8103aaeaf4da92878c622f0
Patch-mainline: v6.2-rc1
References: bsc#1207632

When aops->write_begin() does not initialize fsdata, KMSAN reports
an error passing the latter to aops->write_end().

Fix this by unconditionally initializing fsdata.

Cc: Eric Biggers <ebiggers@kernel.org>
Fixes: c93d8f885809 ("ext4: add basic fs-verity support")
Reported-by: syzbot+9767be679ef5016b6082@syzkaller.appspotmail.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20221121112134.407362-1-glider@google.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Acked-by: Jan Kara <jack@suse.cz>

---
 fs/ext4/verity.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/ext4/verity.c
+++ b/fs/ext4/verity.c
@@ -76,7 +76,7 @@ static int pagecache_write(struct inode
 		size_t n = min_t(size_t, count,
 				 PAGE_SIZE - offset_in_page(pos));
 		struct page *page;
-		void *fsdata;
+		void *fsdata = NULL;
 		int res;
 
 		res = pagecache_write_begin(NULL, inode->i_mapping, pos, n, 0,