linux-kernel - Re: arch/arm/boot/compressed/decompress.c:50: warning: "memmove" redefined

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Date:   Sun, 9 May 2021 17:17:49 +0200
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Russell King - ARM Linux admin <linux@...linux.org.uk>,
        kasan-dev <kasan-dev@...glegroups.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Dmitry Vyukov <dvyukov@...gle.com>
Cc:     Ard Biesheuvel <ardb@...nel.org>,
        Abbott Liu <liuwenliang@...wei.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        kernel test robot <lkp@...el.com>, kbuild-all@...ts.01.org,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: arch/arm/boot/compressed/decompress.c:50: warning: "memmove" redefined

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

On Sun, May 9, 2021 at 2:22 PM Russell King - ARM Linux admin
<linux@...linux.org.uk> wrote:
>
> 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.
>
> On Sun, May 09, 2021 at 11:32:17AM +0800, kernel test robot wrote:
> > 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 <lkp@...el.com>
> >
> > 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 <kaloz@...nwrt.org>
> > :::::: CC: Russell King <rmk+kernel@....linux.org.uk>
> >
> > ---
> > 0-DAY CI Kernel Test Service, Intel Corporation
> > https://lists.01.org/hyperkitty/list/kbuild-all@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!