ether_addr_equal_64bits breakage with gcc-12 - Marc Kleine-Budde

From: Marc Kleine-Budde <mkl@pengutronix.de>
To: Eric Dumazet <edumazet@google.com>
Cc: netdev@vger.kernel.org, Jakub Kicinski <kuba@kernel.org>,
	"David S. Miller" <davem@davemloft.net>
Subject: ether_addr_equal_64bits breakage with gcc-12
Date: Fri, 11 Feb 2022 15:12:13 +0100	[thread overview]
Message-ID: <20220211141213.l4yitk7aifehjymp@pengutronix.de> (raw)

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Hello,

the current arm-linux-gnueabihf-gcc 12 snapshot in Debian breaks (at
least with CONFIG_WERROR=y):

|   CC      net/core/dev.o
| net/core/dev.c: In function ‘bpf_prog_run_generic_xdp’:
| net/core/dev.c:4618:21: warning: ‘ether_addr_equal_64bits’ reading 8 bytes from a region of size 6 [-Wstringop-overread]
|  4618 |         orig_host = ether_addr_equal_64bits(eth->h_dest, skb->dev->dev_addr);
|       |                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| net/core/dev.c:4618:21: note: referencing argument 1 of type ‘const u8[8]’ {aka ‘const unsigned char[8]’}
| net/core/dev.c:4618:21: note: referencing argument 2 of type ‘const u8[8]’ {aka ‘const unsigned char[8]’}
| In file included from net/core/dev.c:91:
| include/linux/etherdevice.h:375:20: note: in a call to function ‘ether_addr_equal_64bits’
|   375 | static inline bool ether_addr_equal_64bits(const u8 addr1[6+2],
|       |                    ^~~~~~~~~~~~~~~~~~~~~~~
| net/core/dev.c:4619:22: warning: ‘is_multicast_ether_addr_64bits’ reading 8 bytes from a region of size 6 [-Wstringop-overread]
|  4619 |         orig_bcast = is_multicast_ether_addr_64bits(eth->h_dest);
|       |                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| net/core/dev.c:4619:22: note: referencing argument 1 of type ‘const u8[8]’ {aka ‘const unsigned char[8]’}
| include/linux/etherdevice.h:137:20: note: in a call to function ‘is_multicast_ether_addr_64bits’
|   137 | static inline bool is_multicast_ether_addr_64bits(const u8 addr[6+2])
|       |                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| net/core/dev.c:4646:27: warning: ‘ether_addr_equal_64bits’ reading 8 bytes from a region of size 6 [-Wstringop-overread]
|  4646 |             (orig_host != ether_addr_equal_64bits(eth->h_dest,
|       |                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|  4647 |                                                   skb->dev->dev_addr)) ||
|       |                                                   ~~~~~~~~~~~~~~~~~~~
| net/core/dev.c:4646:27: note: referencing argument 1 of type ‘const u8[8]’ {aka ‘const unsigned char[8]’}
| net/core/dev.c:4646:27: note: referencing argument 2 of type ‘const u8[8]’ {aka ‘const unsigned char[8]’}
| include/linux/etherdevice.h:375:20: note: in a call to function ‘ether_addr_equal_64bits’
|   375 | static inline bool ether_addr_equal_64bits(const u8 addr1[6+2],
|       |                    ^~~~~~~~~~~~~~~~~~~~~~~
| net/core/dev.c:4648:28: warning: ‘is_multicast_ether_addr_64bits’ reading 8 bytes from a region of size 6 [-Wstringop-overread]
|  4648 |             (orig_bcast != is_multicast_ether_addr_64bits(eth->h_dest))) {
|       |                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| net/core/dev.c:4648:28: note: referencing argument 1 of type ‘const u8[8]’ {aka ‘const unsigned char[8]’}
| include/linux/etherdevice.h:137:20: note: in a call to function ‘is_multicast_ether_addr_64bits’
|   137 | static inline bool is_multicast_ether_addr_64bits(const u8 addr[6+2])
|       |                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

| arm-linux-gnueabihf-gcc -v
| Using built-in specs.
| COLLECT_GCC=/usr/bin/arm-linux-gnueabihf-gcc
| COLLECT_LTO_WRAPPER=/usr/lib/gcc-cross/arm-linux-gnueabihf/12/lto-wrapper
| Target: arm-linux-gnueabihf
| Configured with: ../src/configure -v --with-pkgversion='Debian 12-20220126-1' --with-bugurl=file:///usr/share/doc/gcc-12/README.Bugs --enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++,m2 --prefix=/usr --with-gcc-major-version-only --program-suffix=-12 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-libitm --disable-libquadmath --disable-libquadmath-support --enable-plugin --enable-default-pie --with-system-zlib --enable-libphobos-checking=release --without-target-system-zlib --enable-multiarch --disable-sjlj-exceptions --with-arch=armv7-a+fp --with-float=hard --with-mode=thumb --disable-werror --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=arm-linux-gnueabihf --program-prefix=arm-linux-gnueabihf- --includedir=/usr/arm-linux-gnueabihf/include
| Thread model: posix
| Supported LTO compression algorithms: zlib zstd
| gcc version 12.0.1 20220126 (experimental) [master r12-6872-gf3e6ef7d873] (Debian 12-20220126-1)

regards,
Marc

--
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |

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