Re: [syzbot] Re: [syzbot] [erofs?] KMSAN: uninit-value in z_erofs_lz4_decompress (3)

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@xxxxxxxxxxxxxxx.

***

Subject: Re: [syzbot] [erofs?] KMSAN: uninit-value in z_erofs_lz4_decompress (3)
Author: eadavis@xxxxxx

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

diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 021be5feb1bc..8ac3f96676c4 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -252,7 +252,8 @@ static int z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx *ctx,
 		print_hex_dump(KERN_DEBUG, "[ in]: ", DUMP_PREFIX_OFFSET,
 			       16, 1, src + inputmargin, rq->inputsize, true);
 		print_hex_dump(KERN_DEBUG, "[out]: ", DUMP_PREFIX_OFFSET,
-			       16, 1, out, rq->outputsize, true);
+			       16, 1, out, (ret < 0 && rq->inputsize > 0) ? 
+			       (ret + rq->inputsize) : rq->outputsize, true);
 
 		if (ret >= 0)
 			memset(out + ret, 0, rq->outputsize - ret);