2022-09-29 02:33:50

by Alexey Kardashevskiy

[permalink] [raw]
Subject: [PATCH kernel v3] zstd: Fixing mixed module-builtin objects

With CONFIG_ZSTD_COMPRESS=m and CONFIG_ZSTD_DECOMPRESS=y we end up in
a situation when files from lib/zstd/common/ are compiled once to be
linked later for ZSTD_DECOMPRESS (build-in) and ZSTD_COMPRESS (module)
even though CFLAGS are different for builtins and modules.
So far somehow this was not a problem but enabling LLVM LTO exposes
the problem as:

ld.lld: error: linking module flags 'Code Model': IDs have conflicting values in 'lib/built-in.a(zstd_common.o at 5868)' and 'ld-temp.o'

This particular conflict is caused by KBUILD_CFLAGS=-mcmodel=medium vs.
KBUILD_CFLAGS_MODULE=-mcmodel=large , modules use the large model on
POWERPC as explained at
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/powerpc/Makefile?h=v5.18-rc4#n127
but the current use of common files is wrong anyway.

This works around the issue by introducing a zstd_common module with
shared code.

Cc: Masahiro Yamada <[email protected]>
Signed-off-by: Alexey Kardashevskiy <[email protected]>
[robot found a problem in v2]
Reported-by: kernel test robot <[email protected]>
---
Changes:
v3:
* added EXPORT_SYMBOL_GPL to compile with:
CONFIG_ZSTD_COMMON=m
CONFIG_ZSTD_COMPRESS=m
CONFIG_ZSTD_DECOMPRESS=m
Vast majority of cases have CONFIG_ZSTD_COMMON=y so this went unnoticed
---
lib/zstd/Makefile | 18 ++++++++----------
lib/zstd/common/entropy_common.c | 5 ++++-
lib/zstd/common/zstd_common.c | 10 ++++++++++
lib/Kconfig | 8 ++++++--
4 files changed, 28 insertions(+), 13 deletions(-)

diff --git a/lib/zstd/Makefile b/lib/zstd/Makefile
index fc45339fc3a3..440bd0007ae2 100644
--- a/lib/zstd/Makefile
+++ b/lib/zstd/Makefile
@@ -10,14 +10,10 @@
# ################################################################
obj-$(CONFIG_ZSTD_COMPRESS) += zstd_compress.o
obj-$(CONFIG_ZSTD_DECOMPRESS) += zstd_decompress.o
+obj-$(CONFIG_ZSTD_COMMON) += zstd_common.o

zstd_compress-y := \
zstd_compress_module.o \
- common/debug.o \
- common/entropy_common.o \
- common/error_private.o \
- common/fse_decompress.o \
- common/zstd_common.o \
compress/fse_compress.o \
compress/hist.o \
compress/huf_compress.o \
@@ -33,12 +29,14 @@ zstd_compress-y := \

zstd_decompress-y := \
zstd_decompress_module.o \
- common/debug.o \
- common/entropy_common.o \
- common/error_private.o \
- common/fse_decompress.o \
- common/zstd_common.o \
decompress/huf_decompress.o \
decompress/zstd_ddict.o \
decompress/zstd_decompress.o \
decompress/zstd_decompress_block.o \
+
+zstd_common-y := \
+ common/debug.o \
+ common/entropy_common.o \
+ common/error_private.o \
+ common/fse_decompress.o \
+ common/zstd_common.o \
diff --git a/lib/zstd/common/entropy_common.c b/lib/zstd/common/entropy_common.c
index 53b47a2b52ff..a311808c0d56 100644
--- a/lib/zstd/common/entropy_common.c
+++ b/lib/zstd/common/entropy_common.c
@@ -15,6 +15,7 @@
/* *************************************
* Dependencies
***************************************/
+#include <linux/module.h>
#include "mem.h"
#include "error_private.h" /* ERR_*, ERROR */
#define FSE_STATIC_LINKING_ONLY /* FSE_MIN_TABLELOG */
@@ -239,7 +240,7 @@ size_t FSE_readNCount(
{
return FSE_readNCount_bmi2(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize, /* bmi2 */ 0);
}
-
+EXPORT_SYMBOL_GPL(FSE_readNCount);

/*! HUF_readStats() :
Read compact Huffman tree, saved by HUF_writeCTable().
@@ -255,6 +256,7 @@ size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats,
U32 wksp[HUF_READ_STATS_WORKSPACE_SIZE_U32];
return HUF_readStats_wksp(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, wksp, sizeof(wksp), /* bmi2 */ 0);
}
+EXPORT_SYMBOL_GPL(HUF_readStats);

FORCE_INLINE_TEMPLATE size_t
HUF_readStats_body(BYTE* huffWeight, size_t hwSize, U32* rankStats,
@@ -355,3 +357,4 @@ size_t HUF_readStats_wksp(BYTE* huffWeight, size_t hwSize, U32* rankStats,
(void)bmi2;
return HUF_readStats_body_default(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize);
}
+EXPORT_SYMBOL_GPL(HUF_readStats_wksp);
diff --git a/lib/zstd/common/zstd_common.c b/lib/zstd/common/zstd_common.c
index 3d7e35b309b5..0f1f63be25d9 100644
--- a/lib/zstd/common/zstd_common.c
+++ b/lib/zstd/common/zstd_common.c
@@ -13,6 +13,7 @@
/*-*************************************
* Dependencies
***************************************/
+#include <linux/module.h>
#define ZSTD_DEPS_NEED_MALLOC
#include "zstd_deps.h" /* ZSTD_malloc, ZSTD_calloc, ZSTD_free, ZSTD_memset */
#include "error_private.h"
@@ -35,14 +36,17 @@ const char* ZSTD_versionString(void) { return ZSTD_VERSION_STRING; }
* tells if a return value is an error code
* symbol is required for external callers */
unsigned ZSTD_isError(size_t code) { return ERR_isError(code); }
+EXPORT_SYMBOL_GPL(ZSTD_isError);

/*! ZSTD_getErrorName() :
* provides error code string from function result (useful for debugging) */
const char* ZSTD_getErrorName(size_t code) { return ERR_getErrorName(code); }
+EXPORT_SYMBOL_GPL(ZSTD_getErrorName);

/*! ZSTD_getError() :
* convert a `size_t` function result into a proper ZSTD_errorCode enum */
ZSTD_ErrorCode ZSTD_getErrorCode(size_t code) { return ERR_getErrorCode(code); }
+EXPORT_SYMBOL_GPL(ZSTD_getErrorCode);

/*! ZSTD_getErrorString() :
* provides error code string from enum */
@@ -59,6 +63,7 @@ void* ZSTD_customMalloc(size_t size, ZSTD_customMem customMem)
return customMem.customAlloc(customMem.opaque, size);
return ZSTD_malloc(size);
}
+EXPORT_SYMBOL_GPL(ZSTD_customMalloc);

void* ZSTD_customCalloc(size_t size, ZSTD_customMem customMem)
{
@@ -71,6 +76,7 @@ void* ZSTD_customCalloc(size_t size, ZSTD_customMem customMem)
}
return ZSTD_calloc(1, size);
}
+EXPORT_SYMBOL_GPL(ZSTD_customCalloc);

void ZSTD_customFree(void* ptr, ZSTD_customMem customMem)
{
@@ -81,3 +87,7 @@ void ZSTD_customFree(void* ptr, ZSTD_customMem customMem)
ZSTD_free(ptr);
}
}
+EXPORT_SYMBOL_GPL(ZSTD_customFree);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("Zstd Common");
diff --git a/lib/Kconfig b/lib/Kconfig
index dc1ab2ed1dc6..3ea8941ab18d 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -343,12 +343,16 @@ config LZ4HC_COMPRESS
config LZ4_DECOMPRESS
tristate

+config ZSTD_COMMON
+ select XXHASH
+ tristate
+
config ZSTD_COMPRESS
- select XXHASH
+ select ZSTD_COMMON
tristate

config ZSTD_DECOMPRESS
- select XXHASH
+ select ZSTD_COMMON
tristate

source "lib/xz/Kconfig"
--
2.37.3


2022-09-29 18:10:14

by Masahiro Yamada

[permalink] [raw]
Subject: Re: [PATCH kernel v3] zstd: Fixing mixed module-builtin objects

On Thu, Sep 29, 2022 at 11:08 AM Alexey Kardashevskiy <[email protected]> wrote:
>
> With CONFIG_ZSTD_COMPRESS=m and CONFIG_ZSTD_DECOMPRESS=y we end up in
> a situation when files from lib/zstd/common/ are compiled once to be
> linked later for ZSTD_DECOMPRESS (build-in) and ZSTD_COMPRESS (module)
> even though CFLAGS are different for builtins and modules.
> So far somehow this was not a problem but enabling LLVM LTO exposes
> the problem as:
>
> ld.lld: error: linking module flags 'Code Model': IDs have conflicting values in 'lib/built-in.a(zstd_common.o at 5868)' and 'ld-temp.o'
>
> This particular conflict is caused by KBUILD_CFLAGS=-mcmodel=medium vs.
> KBUILD_CFLAGS_MODULE=-mcmodel=large , modules use the large model on
> POWERPC as explained at
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/powerpc/Makefile?h=v5.18-rc4#n127
> but the current use of common files is wrong anyway.
>
> This works around the issue by introducing a zstd_common module with
> shared code.
>
> Cc: Masahiro Yamada <[email protected]>
> Signed-off-by: Alexey Kardashevskiy <[email protected]>
> [robot found a problem in v2]
> Reported-by: kernel test robot <[email protected]>
> ---
> Changes:
> v3:
> * added EXPORT_SYMBOL_GPL to compile with:
> CONFIG_ZSTD_COMMON=m
> CONFIG_ZSTD_COMPRESS=m
> CONFIG_ZSTD_DECOMPRESS=m
> Vast majority of cases have CONFIG_ZSTD_COMMON=y so this went unnoticed


Applied to linux-kbuild. Thanks.


> ---
> lib/zstd/Makefile | 18 ++++++++----------
> lib/zstd/common/entropy_common.c | 5 ++++-
> lib/zstd/common/zstd_common.c | 10 ++++++++++
> lib/Kconfig | 8 ++++++--
> 4 files changed, 28 insertions(+), 13 deletions(-)
>
> diff --git a/lib/zstd/Makefile b/lib/zstd/Makefile
> index fc45339fc3a3..440bd0007ae2 100644
> --- a/lib/zstd/Makefile
> +++ b/lib/zstd/Makefile
> @@ -10,14 +10,10 @@
> # ################################################################
> obj-$(CONFIG_ZSTD_COMPRESS) += zstd_compress.o
> obj-$(CONFIG_ZSTD_DECOMPRESS) += zstd_decompress.o
> +obj-$(CONFIG_ZSTD_COMMON) += zstd_common.o
>
> zstd_compress-y := \
> zstd_compress_module.o \
> - common/debug.o \
> - common/entropy_common.o \
> - common/error_private.o \
> - common/fse_decompress.o \
> - common/zstd_common.o \
> compress/fse_compress.o \
> compress/hist.o \
> compress/huf_compress.o \
> @@ -33,12 +29,14 @@ zstd_compress-y := \
>
> zstd_decompress-y := \
> zstd_decompress_module.o \
> - common/debug.o \
> - common/entropy_common.o \
> - common/error_private.o \
> - common/fse_decompress.o \
> - common/zstd_common.o \
> decompress/huf_decompress.o \
> decompress/zstd_ddict.o \
> decompress/zstd_decompress.o \
> decompress/zstd_decompress_block.o \
> +
> +zstd_common-y := \
> + common/debug.o \
> + common/entropy_common.o \
> + common/error_private.o \
> + common/fse_decompress.o \
> + common/zstd_common.o \
> diff --git a/lib/zstd/common/entropy_common.c b/lib/zstd/common/entropy_common.c
> index 53b47a2b52ff..a311808c0d56 100644
> --- a/lib/zstd/common/entropy_common.c
> +++ b/lib/zstd/common/entropy_common.c
> @@ -15,6 +15,7 @@
> /* *************************************
> * Dependencies
> ***************************************/
> +#include <linux/module.h>
> #include "mem.h"
> #include "error_private.h" /* ERR_*, ERROR */
> #define FSE_STATIC_LINKING_ONLY /* FSE_MIN_TABLELOG */
> @@ -239,7 +240,7 @@ size_t FSE_readNCount(
> {
> return FSE_readNCount_bmi2(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize, /* bmi2 */ 0);
> }
> -
> +EXPORT_SYMBOL_GPL(FSE_readNCount);
>
> /*! HUF_readStats() :
> Read compact Huffman tree, saved by HUF_writeCTable().
> @@ -255,6 +256,7 @@ size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats,
> U32 wksp[HUF_READ_STATS_WORKSPACE_SIZE_U32];
> return HUF_readStats_wksp(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, wksp, sizeof(wksp), /* bmi2 */ 0);
> }
> +EXPORT_SYMBOL_GPL(HUF_readStats);
>
> FORCE_INLINE_TEMPLATE size_t
> HUF_readStats_body(BYTE* huffWeight, size_t hwSize, U32* rankStats,
> @@ -355,3 +357,4 @@ size_t HUF_readStats_wksp(BYTE* huffWeight, size_t hwSize, U32* rankStats,
> (void)bmi2;
> return HUF_readStats_body_default(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize);
> }
> +EXPORT_SYMBOL_GPL(HUF_readStats_wksp);
> diff --git a/lib/zstd/common/zstd_common.c b/lib/zstd/common/zstd_common.c
> index 3d7e35b309b5..0f1f63be25d9 100644
> --- a/lib/zstd/common/zstd_common.c
> +++ b/lib/zstd/common/zstd_common.c
> @@ -13,6 +13,7 @@
> /*-*************************************
> * Dependencies
> ***************************************/
> +#include <linux/module.h>
> #define ZSTD_DEPS_NEED_MALLOC
> #include "zstd_deps.h" /* ZSTD_malloc, ZSTD_calloc, ZSTD_free, ZSTD_memset */
> #include "error_private.h"
> @@ -35,14 +36,17 @@ const char* ZSTD_versionString(void) { return ZSTD_VERSION_STRING; }
> * tells if a return value is an error code
> * symbol is required for external callers */
> unsigned ZSTD_isError(size_t code) { return ERR_isError(code); }
> +EXPORT_SYMBOL_GPL(ZSTD_isError);
>
> /*! ZSTD_getErrorName() :
> * provides error code string from function result (useful for debugging) */
> const char* ZSTD_getErrorName(size_t code) { return ERR_getErrorName(code); }
> +EXPORT_SYMBOL_GPL(ZSTD_getErrorName);
>
> /*! ZSTD_getError() :
> * convert a `size_t` function result into a proper ZSTD_errorCode enum */
> ZSTD_ErrorCode ZSTD_getErrorCode(size_t code) { return ERR_getErrorCode(code); }
> +EXPORT_SYMBOL_GPL(ZSTD_getErrorCode);
>
> /*! ZSTD_getErrorString() :
> * provides error code string from enum */
> @@ -59,6 +63,7 @@ void* ZSTD_customMalloc(size_t size, ZSTD_customMem customMem)
> return customMem.customAlloc(customMem.opaque, size);
> return ZSTD_malloc(size);
> }
> +EXPORT_SYMBOL_GPL(ZSTD_customMalloc);
>
> void* ZSTD_customCalloc(size_t size, ZSTD_customMem customMem)
> {
> @@ -71,6 +76,7 @@ void* ZSTD_customCalloc(size_t size, ZSTD_customMem customMem)
> }
> return ZSTD_calloc(1, size);
> }
> +EXPORT_SYMBOL_GPL(ZSTD_customCalloc);
>
> void ZSTD_customFree(void* ptr, ZSTD_customMem customMem)
> {
> @@ -81,3 +87,7 @@ void ZSTD_customFree(void* ptr, ZSTD_customMem customMem)
> ZSTD_free(ptr);
> }
> }
> +EXPORT_SYMBOL_GPL(ZSTD_customFree);
> +
> +MODULE_LICENSE("Dual BSD/GPL");
> +MODULE_DESCRIPTION("Zstd Common");
> diff --git a/lib/Kconfig b/lib/Kconfig
> index dc1ab2ed1dc6..3ea8941ab18d 100644
> --- a/lib/Kconfig
> +++ b/lib/Kconfig
> @@ -343,12 +343,16 @@ config LZ4HC_COMPRESS
> config LZ4_DECOMPRESS
> tristate
>
> +config ZSTD_COMMON
> + select XXHASH
> + tristate
> +
> config ZSTD_COMPRESS
> - select XXHASH
> + select ZSTD_COMMON
> tristate
>
> config ZSTD_DECOMPRESS
> - select XXHASH
> + select ZSTD_COMMON
> tristate
>
> source "lib/xz/Kconfig"
> --
> 2.37.3
>


--
Best Regards
Masahiro Yamada

2022-11-11 21:28:38

by Masahiro Yamada

[permalink] [raw]
Subject: Re: [PATCH kernel v3] zstd: Fixing mixed module-builtin objects

On Thu, Sep 29, 2022 at 11:08 AM Alexey Kardashevskiy <[email protected]> wrote:
>
> With CONFIG_ZSTD_COMPRESS=m and CONFIG_ZSTD_DECOMPRESS=y we end up in
> a situation when files from lib/zstd/common/ are compiled once to be
> linked later for ZSTD_DECOMPRESS (build-in) and ZSTD_COMPRESS (module)
> even though CFLAGS are different for builtins and modules.
> So far somehow this was not a problem but enabling LLVM LTO exposes
> the problem as:
>
> ld.lld: error: linking module flags 'Code Model': IDs have conflicting values in 'lib/built-in.a(zstd_common.o at 5868)' and 'ld-temp.o'
>
> This particular conflict is caused by KBUILD_CFLAGS=-mcmodel=medium vs.
> KBUILD_CFLAGS_MODULE=-mcmodel=large , modules use the large model on
> POWERPC as explained at
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/powerpc/Makefile?h=v5.18-rc4#n127
> but the current use of common files is wrong anyway.


BTW, how to reproduce this error?

You referred to the arch/powerpc/Makefile,
but ARCH=powerpc cannot enable Clang LTO.
(powerpc does not select ARCH_SUPPORTS_LTO_CLANG).






> This works around the issue by introducing a zstd_common module with
> shared code.
>
> Cc: Masahiro Yamada <[email protected]>
> Signed-off-by: Alexey Kardashevskiy <[email protected]>
> [robot found a problem in v2]
> Reported-by: kernel test robot <[email protected]>
> ---
> Changes:
> v3:
> * added EXPORT_SYMBOL_GPL to compile with:
> CONFIG_ZSTD_COMMON=m
> CONFIG_ZSTD_COMPRESS=m
> CONFIG_ZSTD_DECOMPRESS=m
> Vast majority of cases have CONFIG_ZSTD_COMMON=y so this went unnoticed
> ---
> lib/zstd/Makefile | 18 ++++++++----------
> lib/zstd/common/entropy_common.c | 5 ++++-
> lib/zstd/common/zstd_common.c | 10 ++++++++++
> lib/Kconfig | 8 ++++++--
> 4 files changed, 28 insertions(+), 13 deletions(-)
>
> diff --git a/lib/zstd/Makefile b/lib/zstd/Makefile
> index fc45339fc3a3..440bd0007ae2 100644
> --- a/lib/zstd/Makefile
> +++ b/lib/zstd/Makefile
> @@ -10,14 +10,10 @@
> # ################################################################
> obj-$(CONFIG_ZSTD_COMPRESS) += zstd_compress.o
> obj-$(CONFIG_ZSTD_DECOMPRESS) += zstd_decompress.o
> +obj-$(CONFIG_ZSTD_COMMON) += zstd_common.o
>
> zstd_compress-y := \
> zstd_compress_module.o \
> - common/debug.o \
> - common/entropy_common.o \
> - common/error_private.o \
> - common/fse_decompress.o \
> - common/zstd_common.o \
> compress/fse_compress.o \
> compress/hist.o \
> compress/huf_compress.o \
> @@ -33,12 +29,14 @@ zstd_compress-y := \
>
> zstd_decompress-y := \
> zstd_decompress_module.o \
> - common/debug.o \
> - common/entropy_common.o \
> - common/error_private.o \
> - common/fse_decompress.o \
> - common/zstd_common.o \
> decompress/huf_decompress.o \
> decompress/zstd_ddict.o \
> decompress/zstd_decompress.o \
> decompress/zstd_decompress_block.o \
> +
> +zstd_common-y := \
> + common/debug.o \
> + common/entropy_common.o \
> + common/error_private.o \
> + common/fse_decompress.o \
> + common/zstd_common.o \
> diff --git a/lib/zstd/common/entropy_common.c b/lib/zstd/common/entropy_common.c
> index 53b47a2b52ff..a311808c0d56 100644
> --- a/lib/zstd/common/entropy_common.c
> +++ b/lib/zstd/common/entropy_common.c
> @@ -15,6 +15,7 @@
> /* *************************************
> * Dependencies
> ***************************************/
> +#include <linux/module.h>
> #include "mem.h"
> #include "error_private.h" /* ERR_*, ERROR */
> #define FSE_STATIC_LINKING_ONLY /* FSE_MIN_TABLELOG */
> @@ -239,7 +240,7 @@ size_t FSE_readNCount(
> {
> return FSE_readNCount_bmi2(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize, /* bmi2 */ 0);
> }
> -
> +EXPORT_SYMBOL_GPL(FSE_readNCount);
>
> /*! HUF_readStats() :
> Read compact Huffman tree, saved by HUF_writeCTable().
> @@ -255,6 +256,7 @@ size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats,
> U32 wksp[HUF_READ_STATS_WORKSPACE_SIZE_U32];
> return HUF_readStats_wksp(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, wksp, sizeof(wksp), /* bmi2 */ 0);
> }
> +EXPORT_SYMBOL_GPL(HUF_readStats);
>
> FORCE_INLINE_TEMPLATE size_t
> HUF_readStats_body(BYTE* huffWeight, size_t hwSize, U32* rankStats,
> @@ -355,3 +357,4 @@ size_t HUF_readStats_wksp(BYTE* huffWeight, size_t hwSize, U32* rankStats,
> (void)bmi2;
> return HUF_readStats_body_default(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize);
> }
> +EXPORT_SYMBOL_GPL(HUF_readStats_wksp);
> diff --git a/lib/zstd/common/zstd_common.c b/lib/zstd/common/zstd_common.c
> index 3d7e35b309b5..0f1f63be25d9 100644
> --- a/lib/zstd/common/zstd_common.c
> +++ b/lib/zstd/common/zstd_common.c
> @@ -13,6 +13,7 @@
> /*-*************************************
> * Dependencies
> ***************************************/
> +#include <linux/module.h>
> #define ZSTD_DEPS_NEED_MALLOC
> #include "zstd_deps.h" /* ZSTD_malloc, ZSTD_calloc, ZSTD_free, ZSTD_memset */
> #include "error_private.h"
> @@ -35,14 +36,17 @@ const char* ZSTD_versionString(void) { return ZSTD_VERSION_STRING; }
> * tells if a return value is an error code
> * symbol is required for external callers */
> unsigned ZSTD_isError(size_t code) { return ERR_isError(code); }
> +EXPORT_SYMBOL_GPL(ZSTD_isError);
>
> /*! ZSTD_getErrorName() :
> * provides error code string from function result (useful for debugging) */
> const char* ZSTD_getErrorName(size_t code) { return ERR_getErrorName(code); }
> +EXPORT_SYMBOL_GPL(ZSTD_getErrorName);
>
> /*! ZSTD_getError() :
> * convert a `size_t` function result into a proper ZSTD_errorCode enum */
> ZSTD_ErrorCode ZSTD_getErrorCode(size_t code) { return ERR_getErrorCode(code); }
> +EXPORT_SYMBOL_GPL(ZSTD_getErrorCode);
>
> /*! ZSTD_getErrorString() :
> * provides error code string from enum */
> @@ -59,6 +63,7 @@ void* ZSTD_customMalloc(size_t size, ZSTD_customMem customMem)
> return customMem.customAlloc(customMem.opaque, size);
> return ZSTD_malloc(size);
> }
> +EXPORT_SYMBOL_GPL(ZSTD_customMalloc);
>
> void* ZSTD_customCalloc(size_t size, ZSTD_customMem customMem)
> {
> @@ -71,6 +76,7 @@ void* ZSTD_customCalloc(size_t size, ZSTD_customMem customMem)
> }
> return ZSTD_calloc(1, size);
> }
> +EXPORT_SYMBOL_GPL(ZSTD_customCalloc);
>
> void ZSTD_customFree(void* ptr, ZSTD_customMem customMem)
> {
> @@ -81,3 +87,7 @@ void ZSTD_customFree(void* ptr, ZSTD_customMem customMem)
> ZSTD_free(ptr);
> }
> }
> +EXPORT_SYMBOL_GPL(ZSTD_customFree);
> +
> +MODULE_LICENSE("Dual BSD/GPL");
> +MODULE_DESCRIPTION("Zstd Common");
> diff --git a/lib/Kconfig b/lib/Kconfig
> index dc1ab2ed1dc6..3ea8941ab18d 100644
> --- a/lib/Kconfig
> +++ b/lib/Kconfig
> @@ -343,12 +343,16 @@ config LZ4HC_COMPRESS
> config LZ4_DECOMPRESS
> tristate
>
> +config ZSTD_COMMON
> + select XXHASH
> + tristate
> +
> config ZSTD_COMPRESS
> - select XXHASH
> + select ZSTD_COMMON
> tristate
>
> config ZSTD_DECOMPRESS
> - select XXHASH
> + select ZSTD_COMMON
> tristate
>
> source "lib/xz/Kconfig"
> --
> 2.37.3
>


--
Best Regards
Masahiro Yamada

2022-11-14 01:27:43

by Alexey Kardashevskiy

[permalink] [raw]
Subject: Re: [PATCH kernel v3] zstd: Fixing mixed module-builtin objects



On 12/11/2022 07:58, Masahiro Yamada wrote:
> On Thu, Sep 29, 2022 at 11:08 AM Alexey Kardashevskiy <[email protected]> wrote:
>>
>> With CONFIG_ZSTD_COMPRESS=m and CONFIG_ZSTD_DECOMPRESS=y we end up in
>> a situation when files from lib/zstd/common/ are compiled once to be
>> linked later for ZSTD_DECOMPRESS (build-in) and ZSTD_COMPRESS (module)
>> even though CFLAGS are different for builtins and modules.
>> So far somehow this was not a problem but enabling LLVM LTO exposes
>> the problem as:
>>
>> ld.lld: error: linking module flags 'Code Model': IDs have conflicting values in 'lib/built-in.a(zstd_common.o at 5868)' and 'ld-temp.o'
>>
>> This particular conflict is caused by KBUILD_CFLAGS=-mcmodel=medium vs.
>> KBUILD_CFLAGS_MODULE=-mcmodel=large , modules use the large model on
>> POWERPC as explained at
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/powerpc/Makefile?h=v5.18-rc4#n127
>> but the current use of common files is wrong anyway.
>
>
> BTW, how to reproduce this error?
>
> You referred to the arch/powerpc/Makefile,
> but ARCH=powerpc cannot enable Clang LTO.
> (powerpc does not select ARCH_SUPPORTS_LTO_CLANG).


I posted a patch for that a while back but it did not get much interest
as there appears to be an alternative to LTO which does not require the
compiler support, I forgot the name of that thing and changed the
employer since then so lost track of this entirely :)

https://patchwork.ozlabs.org/project/linuxppc-dev/patch/[email protected]/


>
>
>
>
>
>> This works around the issue by introducing a zstd_common module with
>> shared code.
>>
>> Cc: Masahiro Yamada <[email protected]>
>> Signed-off-by: Alexey Kardashevskiy <[email protected]>
>> [robot found a problem in v2]
>> Reported-by: kernel test robot <[email protected]>
>> ---
>> Changes:
>> v3:
>> * added EXPORT_SYMBOL_GPL to compile with:
>> CONFIG_ZSTD_COMMON=m
>> CONFIG_ZSTD_COMPRESS=m
>> CONFIG_ZSTD_DECOMPRESS=m
>> Vast majority of cases have CONFIG_ZSTD_COMMON=y so this went unnoticed
>> ---
>> lib/zstd/Makefile | 18 ++++++++----------
>> lib/zstd/common/entropy_common.c | 5 ++++-
>> lib/zstd/common/zstd_common.c | 10 ++++++++++
>> lib/Kconfig | 8 ++++++--
>> 4 files changed, 28 insertions(+), 13 deletions(-)
>>
>> diff --git a/lib/zstd/Makefile b/lib/zstd/Makefile
>> index fc45339fc3a3..440bd0007ae2 100644
>> --- a/lib/zstd/Makefile
>> +++ b/lib/zstd/Makefile
>> @@ -10,14 +10,10 @@
>> # ################################################################
>> obj-$(CONFIG_ZSTD_COMPRESS) += zstd_compress.o
>> obj-$(CONFIG_ZSTD_DECOMPRESS) += zstd_decompress.o
>> +obj-$(CONFIG_ZSTD_COMMON) += zstd_common.o
>>
>> zstd_compress-y := \
>> zstd_compress_module.o \
>> - common/debug.o \
>> - common/entropy_common.o \
>> - common/error_private.o \
>> - common/fse_decompress.o \
>> - common/zstd_common.o \
>> compress/fse_compress.o \
>> compress/hist.o \
>> compress/huf_compress.o \
>> @@ -33,12 +29,14 @@ zstd_compress-y := \
>>
>> zstd_decompress-y := \
>> zstd_decompress_module.o \
>> - common/debug.o \
>> - common/entropy_common.o \
>> - common/error_private.o \
>> - common/fse_decompress.o \
>> - common/zstd_common.o \
>> decompress/huf_decompress.o \
>> decompress/zstd_ddict.o \
>> decompress/zstd_decompress.o \
>> decompress/zstd_decompress_block.o \
>> +
>> +zstd_common-y := \
>> + common/debug.o \
>> + common/entropy_common.o \
>> + common/error_private.o \
>> + common/fse_decompress.o \
>> + common/zstd_common.o \
>> diff --git a/lib/zstd/common/entropy_common.c b/lib/zstd/common/entropy_common.c
>> index 53b47a2b52ff..a311808c0d56 100644
>> --- a/lib/zstd/common/entropy_common.c
>> +++ b/lib/zstd/common/entropy_common.c
>> @@ -15,6 +15,7 @@
>> /* *************************************
>> * Dependencies
>> ***************************************/
>> +#include <linux/module.h>
>> #include "mem.h"
>> #include "error_private.h" /* ERR_*, ERROR */
>> #define FSE_STATIC_LINKING_ONLY /* FSE_MIN_TABLELOG */
>> @@ -239,7 +240,7 @@ size_t FSE_readNCount(
>> {
>> return FSE_readNCount_bmi2(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize, /* bmi2 */ 0);
>> }
>> -
>> +EXPORT_SYMBOL_GPL(FSE_readNCount);
>>
>> /*! HUF_readStats() :
>> Read compact Huffman tree, saved by HUF_writeCTable().
>> @@ -255,6 +256,7 @@ size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats,
>> U32 wksp[HUF_READ_STATS_WORKSPACE_SIZE_U32];
>> return HUF_readStats_wksp(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, wksp, sizeof(wksp), /* bmi2 */ 0);
>> }
>> +EXPORT_SYMBOL_GPL(HUF_readStats);
>>
>> FORCE_INLINE_TEMPLATE size_t
>> HUF_readStats_body(BYTE* huffWeight, size_t hwSize, U32* rankStats,
>> @@ -355,3 +357,4 @@ size_t HUF_readStats_wksp(BYTE* huffWeight, size_t hwSize, U32* rankStats,
>> (void)bmi2;
>> return HUF_readStats_body_default(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize);
>> }
>> +EXPORT_SYMBOL_GPL(HUF_readStats_wksp);
>> diff --git a/lib/zstd/common/zstd_common.c b/lib/zstd/common/zstd_common.c
>> index 3d7e35b309b5..0f1f63be25d9 100644
>> --- a/lib/zstd/common/zstd_common.c
>> +++ b/lib/zstd/common/zstd_common.c
>> @@ -13,6 +13,7 @@
>> /*-*************************************
>> * Dependencies
>> ***************************************/
>> +#include <linux/module.h>
>> #define ZSTD_DEPS_NEED_MALLOC
>> #include "zstd_deps.h" /* ZSTD_malloc, ZSTD_calloc, ZSTD_free, ZSTD_memset */
>> #include "error_private.h"
>> @@ -35,14 +36,17 @@ const char* ZSTD_versionString(void) { return ZSTD_VERSION_STRING; }
>> * tells if a return value is an error code
>> * symbol is required for external callers */
>> unsigned ZSTD_isError(size_t code) { return ERR_isError(code); }
>> +EXPORT_SYMBOL_GPL(ZSTD_isError);
>>
>> /*! ZSTD_getErrorName() :
>> * provides error code string from function result (useful for debugging) */
>> const char* ZSTD_getErrorName(size_t code) { return ERR_getErrorName(code); }
>> +EXPORT_SYMBOL_GPL(ZSTD_getErrorName);
>>
>> /*! ZSTD_getError() :
>> * convert a `size_t` function result into a proper ZSTD_errorCode enum */
>> ZSTD_ErrorCode ZSTD_getErrorCode(size_t code) { return ERR_getErrorCode(code); }
>> +EXPORT_SYMBOL_GPL(ZSTD_getErrorCode);
>>
>> /*! ZSTD_getErrorString() :
>> * provides error code string from enum */
>> @@ -59,6 +63,7 @@ void* ZSTD_customMalloc(size_t size, ZSTD_customMem customMem)
>> return customMem.customAlloc(customMem.opaque, size);
>> return ZSTD_malloc(size);
>> }
>> +EXPORT_SYMBOL_GPL(ZSTD_customMalloc);
>>
>> void* ZSTD_customCalloc(size_t size, ZSTD_customMem customMem)
>> {
>> @@ -71,6 +76,7 @@ void* ZSTD_customCalloc(size_t size, ZSTD_customMem customMem)
>> }
>> return ZSTD_calloc(1, size);
>> }
>> +EXPORT_SYMBOL_GPL(ZSTD_customCalloc);
>>
>> void ZSTD_customFree(void* ptr, ZSTD_customMem customMem)
>> {
>> @@ -81,3 +87,7 @@ void ZSTD_customFree(void* ptr, ZSTD_customMem customMem)
>> ZSTD_free(ptr);
>> }
>> }
>> +EXPORT_SYMBOL_GPL(ZSTD_customFree);
>> +
>> +MODULE_LICENSE("Dual BSD/GPL");
>> +MODULE_DESCRIPTION("Zstd Common");
>> diff --git a/lib/Kconfig b/lib/Kconfig
>> index dc1ab2ed1dc6..3ea8941ab18d 100644
>> --- a/lib/Kconfig
>> +++ b/lib/Kconfig
>> @@ -343,12 +343,16 @@ config LZ4HC_COMPRESS
>> config LZ4_DECOMPRESS
>> tristate
>>
>> +config ZSTD_COMMON
>> + select XXHASH
>> + tristate
>> +
>> config ZSTD_COMPRESS
>> - select XXHASH
>> + select ZSTD_COMMON
>> tristate
>>
>> config ZSTD_DECOMPRESS
>> - select XXHASH
>> + select ZSTD_COMMON
>> tristate
>>
>> source "lib/xz/Kconfig"
>> --
>> 2.37.3
>>
>
>

--
Alexey