Re: [syzbot] [PATCH] test warning in squashfs_read_data

[syzbot <syzbot+32d3767580a1ea339a81@syzkaller.appspotmail.com>]

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Subject: [PATCH] test warning in squashfs_read_data
Author: lizhi.xu@windriver.com

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git ac347a0655db

diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index 581ce9519339..cf21494e3994 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -330,6 +330,12 @@ int squashfs_read_data(struct super_block *sb, u64 index, int length,
 	if (next_index)
 		*next_index = index + length;
 
+	printk("l:%d, i: %d, ol: %d, mbu: %d, %s\n", length, index, output->length,
+			msblk->bytes_used, __func__);
+	if (!length) {
+		res = -EIO;
+		goto out;
+	}
 	res = squashfs_bio_read(sb, index, length, &bio, &offset);
 	if (res)
 		goto out;