releases/6.2.15/module-decompress-never-use-kunmap-for-local-un-mapp.patch

From 8ceaedad8ada6b62d7dcdb3ed286719805e70337 Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Wed, 15 Mar 2023 13:52:56 +0100
Subject: module/decompress: Never use kunmap() for local un-mappings

From: Fabio M. De Francesco <fmdefrancesco@gmail.com>

[ Upstream commit 3c17655ab13704582fe25e8ea3200a9b2f8bf20a ]

Use kunmap_local() to unmap pages locally mapped with kmap_local_page().

kunmap_local() must be called on the kernel virtual address returned by
kmap_local_page(), differently from how we use kunmap() which instead
expects the mapped page as its argument.

In module_zstd_decompress() we currently map with kmap_local_page() and
unmap with kunmap(). This breaks the code and so it should be fixed.

Cc: Piotr Gorski <piotrgorski@cachyos.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Fixes: 169a58ad824d ("module/decompress: Support zstd in-kernel decompression")
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Piotr Gorski <piotrgorski@cachyos.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/module/decompress.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/module/decompress.c b/kernel/module/decompress.c
index bb79ac1a6d8f7..7ddc87bee2741 100644
--- a/kernel/module/decompress.c
+++ b/kernel/module/decompress.c
@@ -267,7 +267,7 @@ static ssize_t module_zstd_decompress(struct load_info *info,
 		zstd_dec.size = PAGE_SIZE;
 
 		ret = zstd_decompress_stream(dstream, &zstd_dec, &zstd_buf);
-		kunmap(page);
+		kunmap_local(zstd_dec.dst);
 		retval = zstd_get_error_code(ret);
 		if (retval)
 			break;
-- 
2.39.2