arch/arm/boot/compressed/decompress.c:50: warning: "memmove" redefined

DISCUSSION kernel test robot 3 participants 4 messages May 9, 2021

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kernel test robot

author build bot

2021-05-09 03:32 UTC #0 lore raw

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   b741596468b010af2846b75f5e75a842ce344a6e
commit: 421015713b306e47af95d4d61cdfbd96d462e4cb ARM: 9017/2: Enable KASan for ARM
date:   6 months ago
config: arm-randconfig-r015-20210509 (attached as .config)
compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0

reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=421015713b306e47af95d4d61cdfbd96d462e4cb
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 421015713b306e47af95d4d61cdfbd96d462e4cb
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross W=1 ARCH=arm

If you fix the issue, kindly add following tag as appropriate

Reported-by kernel test robot <[email protected]>

All warnings (new ones prefixed by >>):

>> arch/arm/boot/compressed/decompress.c:50: warning: "memmove" redefined

50 | #define memmove memmove
|
In file included from arch/arm/boot/compressed/decompress.c:8:
arch/arm/include/asm/string.h:59: note: this is the location of the previous definition
59 | #define memmove(dst, src, len) __memmove(dst, src, len)
|
arch/arm/boot/compressed/decompress.c:51: warning: "memcpy" redefined
51 | #define memcpy memcpy
|
In file included from arch/arm/boot/compressed/decompress.c:8:
arch/arm/include/asm/string.h:58: note: this is the location of the previous definition
58 | #define memcpy(dst, src, len) __memcpy(dst, src, len)
|
arch/arm/boot/compressed/decompress.c:59:5: warning: no previous prototype for 'do_decompress' [-Wmissing-prototypes]
59 | int do_decompress(u8 *input, int len, u8 *output, void (*error)(char *x))
| ^~~~~~~~~~~~~

vim +/memmove +50 arch/arm/boot/compressed/decompress.c

6e8699f7d68589 Albin Tonnerre 2010-04-03 48

a7f464f3db93ae Imre Kaloz     2012-01-26  49  #ifdef CONFIG_KERNEL_XZ
a7f464f3db93ae Imre Kaloz     2012-01-26 @50  #define memmove memmove
a7f464f3db93ae Imre Kaloz     2012-01-26  51  #define memcpy memcpy
a7f464f3db93ae Imre Kaloz     2012-01-26  52  #include "../../../../lib/decompress_unxz.c"
a7f464f3db93ae Imre Kaloz     2012-01-26  53  #endif
a7f464f3db93ae Imre Kaloz     2012-01-26  54

:::::: The code at line 50 was first introduced by commit
:::::: a7f464f3db93ae5492bee6f6e48939fd8a45fa99 ARM: 7001/2: Wire up support for the XZ decompressor

:::::: TO: Imre Kaloz <[email protected]> :::::: CC: Russell King <[email protected]>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

Russell King - ARM Linux admin

2021-05-09 12:22 UTC #1 lore raw

Maybe the KASan folk can look into this, it isn't obvious how to fix this, since XZ needs memcpy/memmove #defined to avoid using its own version. Having KASan override these with a #define is all very well, but it makes the behaviour of lib/decompress_unxz.c indeterminant if we get rid of the definitions the XZ support added.

Quoted 59 lines · kernel test robot

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   b741596468b010af2846b75f5e75a842ce344a6e
commit: 421015713b306e47af95d4d61cdfbd96d462e4cb ARM: 9017/2: Enable KASan for ARM
date:   6 months ago
config: arm-randconfig-r015-20210509 (attached as .config)
compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=421015713b306e47af95d4d61cdfbd96d462e4cb
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 421015713b306e47af95d4d61cdfbd96d462e4cb
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross W=1 ARCH=arm
If you fix the issue, kindly add following tag as appropriate
Reported-by kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
Quoted 1 line
Quoted 1 line
arch/arm/boot/compressed/decompress.c:50: warning: "memmove" redefined
50 | #define memmove memmove
|
In file included from arch/arm/boot/compressed/decompress.c:8:
arch/arm/include/asm/string.h:59: note: this is the location of the previous definition
59 | #define memmove(dst, src, len) __memmove(dst, src, len)
|
arch/arm/boot/compressed/decompress.c:51: warning: "memcpy" redefined
51 | #define memcpy memcpy
|
In file included from arch/arm/boot/compressed/decompress.c:8:
arch/arm/include/asm/string.h:58: note: this is the location of the previous definition
58 | #define memcpy(dst, src, len) __memcpy(dst, src, len)
|
arch/arm/boot/compressed/decompress.c:59:5: warning: no previous prototype for 'do_decompress' [-Wmissing-prototypes]
59 | int do_decompress(u8 *input, int len, u8 *output, void (*error)(char *x))
| ^~~~~~~~~~~~~
vim +/memmove +50 arch/arm/boot/compressed/decompress.c
6e8699f7d68589 Albin Tonnerre 2010-04-03 48
a7f464f3db93ae Imre Kaloz     2012-01-26  49  #ifdef CONFIG_KERNEL_XZ
a7f464f3db93ae Imre Kaloz     2012-01-26 @50  #define memmove memmove
a7f464f3db93ae Imre Kaloz     2012-01-26  51  #define memcpy memcpy
a7f464f3db93ae Imre Kaloz     2012-01-26  52  #include "../../../../lib/decompress_unxz.c"
a7f464f3db93ae Imre Kaloz     2012-01-26  53  #endif
a7f464f3db93ae Imre Kaloz     2012-01-26  54  
:::::: The code at line 50 was first introduced by commit
:::::: a7f464f3db93ae5492bee6f6e48939fd8a45fa99 ARM: 7001/2: Wire up support for the XZ decompressor
:::::: TO: Imre Kaloz <[email protected]> :::::: CC: Russell King <[email protected]>
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

Signature · 2 lines

RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

Linus Walleij

2021-05-09 15:17 UTC #2 lore raw

OK, paging in the KSan mailing list and key people.

Certainly this problem must be the same on all platforms using an XZ-compressed kernel and not just Arm?

What I wonder is why the other platforms that use XZ compression don't redefine memmove and memcpy in their decompress.c clause for XZ?

Can we just delete these two lines?
#define memmove memmove
#define memcpy memcpy

Imre?

I can test some platforms without these defines later tonight and see what happens.

Yours,
Linus Walleij

Quoted 73 lines · Russell King - ARM Linux admin

Maybe the KASan folk can look into this, it isn't obvious how to fix this, since XZ needs memcpy/memmove #defined to avoid using its own version. Having KASan override these with a #define is all very well, but it makes the behaviour of lib/decompress_unxz.c indeterminant if we get rid of the definitions the XZ support added.
Quoted 53 lines · kernel test robot
tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   b741596468b010af2846b75f5e75a842ce344a6e
commit: 421015713b306e47af95d4d61cdfbd96d462e4cb ARM: 9017/2: Enable KASan for ARM
date:   6 months ago
config: arm-randconfig-r015-20210509 (attached as .config)
compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=421015713b306e47af95d4d61cdfbd96d462e4cb
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 421015713b306e47af95d4d61cdfbd96d462e4cb
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross W=1 ARCH=arm
If you fix the issue, kindly add following tag as appropriate
Reported-by kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
Quoted 1 line
Quoted 1 line
arch/arm/boot/compressed/decompress.c:50: warning: "memmove" redefined
50 | #define memmove memmove
|
In file included from arch/arm/boot/compressed/decompress.c:8:
arch/arm/include/asm/string.h:59: note: this is the location of the previous definition
59 | #define memmove(dst, src, len) __memmove(dst, src, len)
|
arch/arm/boot/compressed/decompress.c:51: warning: "memcpy" redefined
51 | #define memcpy memcpy
|
In file included from arch/arm/boot/compressed/decompress.c:8:
arch/arm/include/asm/string.h:58: note: this is the location of the previous definition
58 | #define memcpy(dst, src, len) __memcpy(dst, src, len)
|
arch/arm/boot/compressed/decompress.c:59:5: warning: no previous prototype for 'do_decompress' [-Wmissing-prototypes]
59 | int do_decompress(u8 *input, int len, u8 *output, void (*error)(char *x))
| ^~~~~~~~~~~~~
vim +/memmove +50 arch/arm/boot/compressed/decompress.c
6e8699f7d68589 Albin Tonnerre 2010-04-03 48
a7f464f3db93ae Imre Kaloz     2012-01-26  49  #ifdef CONFIG_KERNEL_XZ
a7f464f3db93ae Imre Kaloz     2012-01-26 @50  #define memmove memmove
a7f464f3db93ae Imre Kaloz     2012-01-26  51  #define memcpy memcpy
a7f464f3db93ae Imre Kaloz     2012-01-26  52  #include "../../../../lib/decompress_unxz.c"
a7f464f3db93ae Imre Kaloz     2012-01-26  53  #endif
a7f464f3db93ae Imre Kaloz     2012-01-26  54
:::::: The code at line 50 was first introduced by commit
:::::: a7f464f3db93ae5492bee6f6e48939fd8a45fa99 ARM: 7001/2: Wire up support for the XZ decompressor
Quoted 6 lines
:::::: TO: Imre Kaloz <[email protected]> :::::: CC: Russell King <[email protected]>
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

Russell King - ARM Linux admin

2021-05-09 16:25 UTC #3 lore raw

Quoted 5 lines · Linus Walleij

OK, paging in the KSan mailing list and key people.
Certainly this problem must be the same on all platforms using an XZ-compressed kernel and not just Arm?

Quoted 7 lines

What I wonder is why the other platforms that use XZ compression don't redefine memmove and memcpy in their decompress.c clause for XZ?
Can we just delete these two lines?
#define memmove memmove
#define memcpy memcpy

We can't. XZ has:

#ifndef memmove
/* Not static to avoid a conflict with the prototype in the Linux
* headers. */
void *memmove(void *dest, const void *src, size_t size) {
...
}
#endif

So, if memmove is not defined in the preprocessor, the code will create its own implementation. memmove() is also defined in arch/arm/boot/compressed/string.c for use with other decompressors, so the local version in lib/decompress_unxz.c will conflict and cause a link time error.

The addition of KASan added this to arch/arm/include/asm/string.h:

#if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__) #define memcpy(dst, src, len) __memcpy(dst, src, len) #define memmove(dst, src, len) __memmove(dst, src, len) #define memset(s, c, n) __memset(s, c, n)

#ifndef __NO_FORTIFY
#define __NO_FORTIFY /* FORTIFY_SOURCE uses __builtin_memcpy, etc. */ #endif

#endif

created a conditional definition of memmove in the preprocessor, which ultimately caused this problem. lib/decompress_unxz.c wants it defined in the preprocessor _if_ one has a local implementation (we do.)

Given that KASan should be disabled in the decompressor, maybe the conditional added by KASan to asm/string.h is insufficient? The makefile has:

KASAN_SANITIZE := n

So really we should not be playing _any_ KASan games in the decompressor code.

Signature · 2 lines

RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!