module/decompress: Never use kunmap() for local un-mappings

[PATCH] module/decompress: Never use kunmap() for local un-mappings

Posted by Fabio M. De Francesco 2 years, 11 months ago

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>
---
 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 bb79ac1a6d8f..7ddc87bee274 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

Re: [PATCH] module/decompress: Never use kunmap() for local un-mappings

Posted by Luis Chamberlain 2 years, 10 months ago

From: Luis Chamberlain <mcgrof@kernel.org>

On Wed, 15 Mar 2023 13:52:56 +0100, Fabio M. De Francesco wrote:
> 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.
> 
> [...]

Applied, thanks!

[1/1] module/decompress: Never use kunmap() for local un-mappings
      commit: 3c17655ab13704582fe25e8ea3200a9b2f8bf20a

  Luis

Re: [PATCH] module/decompress: Never use kunmap() for local un-mappings

Posted by Piotr Gorski 2 years, 10 months ago

Reviewed-by: Piotr Gorski <piotrgorski@cachyos.org>

W dniu 15.03.2023 o 13:52, Fabio M. De Francesco pisze:
> 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>
> ---
>   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 bb79ac1a6d8f..7ddc87bee274 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;

Re: [PATCH] module/decompress: Never use kunmap() for local un-mappings

Posted by Piotr Gorski 2 years, 10 months ago

Reviewed-by: Piotr Gorski <piotrgorski@cachyos.org>

W dniu 15.03.2023 o 13:52, Fabio M. De Francesco pisze:
> 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>
> ---
>   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 bb79ac1a6d8f..7ddc87bee274 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;

Re: [PATCH] module/decompress: Never use kunmap() for local un-mappings

Posted by Stephen Boyd 2 years, 11 months ago

Quoting Fabio M. De Francesco (2023-03-15 05:52:56)
> 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>

Re: [PATCH] module/decompress: Never use kunmap() for local un-mappings

Posted by Ira Weiny 2 years, 11 months ago

Fabio M. De Francesco wrote:
> 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>

Reviewed-by: 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>
> ---
>  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 bb79ac1a6d8f..7ddc87bee274 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
>