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

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Message-ID: <0000000000005860a2060d9274da@google.com>
Date: Thu, 28 Dec 2023 06:08:48 -0800
From: syzbot <syzbot+6c746eea496f34b3161d@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org
Subject: Re: [syzbot] Re: [syzbot] [erofs?] KMSAN: uninit-value in
 z_erofs_lz4_decompress (2)

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Subject: Re: [syzbot] [erofs?] KMSAN: uninit-value in z_erofs_lz4_decompress (2)
Author: eadavis@...com

please test uninit-value in z_erofs_lz4_decompress (2)

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git fbafc3e621c3

diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 021be5feb1bc..c0983c3db77f 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -250,7 +250,8 @@ 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 ? min_t(unsigned int, 
+				       rq->outputsize, rq->inputsize) : rq->outputsize, true);
 
 		if (ret >= 0)
 			memset(out + ret, 0, rq->outputsize - ret);