linux-kernel - Re: [syzbot] Re: [syzbot] [erofs?] KMSAN: uninit-value in z_erofs_lz4

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Date: Thu, 01 Feb 2024 15:30:55 -0800
From: syzbot <syzbot+88ad8b0517a9d3bb9dc8@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org
Subject: Re: [syzbot] Re: [syzbot] [erofs?] KMSAN: uninit-value in
 z_erofs_lz4_decompress (3)

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

#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);