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Date:   Wed, 22 Nov 2023 05:25:49 +0800
From:   kernel test robot <lkp@intel.com>
To:     Edward Cree <ecree.xilinx@gmail.com>
Cc:     llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev,
        linux-kernel@vger.kernel.org, Jakub Kicinski <kuba@kernel.org>,
        Andy Moreton <andy.moreton@amd.com>,
        Simon Horman <simon.horman@corigine.com>
Subject: drivers/net/ethernet/sfc/selftest.c:48:16: warning: field ip within
 'struct efx_loopback_payload::(anonymous at
 drivers/net/ethernet/sfc/selftest.c:46:2)' is less aligned than 'struct
 iphdr' and is usually due to 'struct efx_loopback_payload::(anonymous a...
Message-ID: <202311220537.geMTr31W-lkp@intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
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Precedence: bulk

Hi Edward,

FYI, the error/warning still remains.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   98b1cc82c4affc16f5598d4fa14b1858671b2263
commit: 55c1528f9b97ff3b7efad73e8f79627fc2efb298 sfc: fix field-spanning memcpy in selftest
date:   4 months ago
config: arm-randconfig-003-20231122 (https://download.01.org/0day-ci/archive/20231122/202311220537.geMTr31W-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231122/202311220537.geMTr31W-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202311220537.geMTr31W-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/net/ethernet/sfc/selftest.c:48:16: warning: field ip within 'struct efx_loopback_payload::(anonymous at drivers/net/ethernet/sfc/selftest.c:46:2)' is less aligned than 'struct iphdr' and is usually due to 'struct efx_loopback_payload::(anonymous at drivers/net/ethernet/sfc/selftest.c:46:2)' being packed, which can lead to unaligned accesses [-Wunaligned-access]
      48 |                 struct iphdr ip;
         |                              ^
>> drivers/net/ethernet/sfc/selftest.c:48:16: warning: field ip within 'struct efx_loopback_payload::(unnamed at drivers/net/ethernet/sfc/selftest.c:46:2)' is less aligned than 'struct iphdr' and is usually due to 'struct efx_loopback_payload::(unnamed at drivers/net/ethernet/sfc/selftest.c:46:2)' being packed, which can lead to unaligned accesses [-Wunaligned-access]
   2 warnings generated.
--
>> drivers/net/ethernet/sfc/falcon/selftest.c:45:16: warning: field ip within 'struct ef4_loopback_payload::(anonymous at drivers/net/ethernet/sfc/falcon/selftest.c:43:2)' is less aligned than 'struct iphdr' and is usually due to 'struct ef4_loopback_payload::(anonymous at drivers/net/ethernet/sfc/falcon/selftest.c:43:2)' being packed, which can lead to unaligned accesses [-Wunaligned-access]
      45 |                 struct iphdr ip;
         |                              ^
>> drivers/net/ethernet/sfc/falcon/selftest.c:45:16: warning: field ip within 'struct ef4_loopback_payload::(unnamed at drivers/net/ethernet/sfc/falcon/selftest.c:43:2)' is less aligned than 'struct iphdr' and is usually due to 'struct ef4_loopback_payload::(unnamed at drivers/net/ethernet/sfc/falcon/selftest.c:43:2)' being packed, which can lead to unaligned accesses [-Wunaligned-access]
   2 warnings generated.


vim +48 drivers/net/ethernet/sfc/selftest.c

93e5dfa59b0e26 drivers/net/ethernet/sfc/selftest.c Ben Hutchings   2012-02-28  37  
3273c2e8c66a21 drivers/net/sfc/selftest.c          Ben Hutchings   2008-05-07  38  /*
3273c2e8c66a21 drivers/net/sfc/selftest.c          Ben Hutchings   2008-05-07  39   * Loopback test packet structure
3273c2e8c66a21 drivers/net/sfc/selftest.c          Ben Hutchings   2008-05-07  40   *
3273c2e8c66a21 drivers/net/sfc/selftest.c          Ben Hutchings   2008-05-07  41   * The self-test should stress every RSS vector, and unfortunately
3273c2e8c66a21 drivers/net/sfc/selftest.c          Ben Hutchings   2008-05-07  42   * Falcon only performs RSS on TCP/UDP packets.
3273c2e8c66a21 drivers/net/sfc/selftest.c          Ben Hutchings   2008-05-07  43   */
3273c2e8c66a21 drivers/net/sfc/selftest.c          Ben Hutchings   2008-05-07  44  struct efx_loopback_payload {
cf60ed46962992 drivers/net/ethernet/sfc/selftest.c Edward Cree     2023-06-23  45  	char pad[2]; /* Ensures ip is 4-byte aligned */
55c1528f9b97ff drivers/net/ethernet/sfc/selftest.c Edward Cree     2023-07-28  46  	struct_group_attr(packet, __packed,
3273c2e8c66a21 drivers/net/sfc/selftest.c          Ben Hutchings   2008-05-07  47  		struct ethhdr header;
3273c2e8c66a21 drivers/net/sfc/selftest.c          Ben Hutchings   2008-05-07 @48  		struct iphdr ip;
3273c2e8c66a21 drivers/net/sfc/selftest.c          Ben Hutchings   2008-05-07  49  		struct udphdr udp;
3273c2e8c66a21 drivers/net/sfc/selftest.c          Ben Hutchings   2008-05-07  50  		__be16 iteration;
1d20a16062e771 drivers/net/ethernet/sfc/selftest.c David S. Miller 2015-04-17  51  		char msg[64];
55c1528f9b97ff drivers/net/ethernet/sfc/selftest.c Edward Cree     2023-07-28  52  	);
cf60ed46962992 drivers/net/ethernet/sfc/selftest.c Edward Cree     2023-06-23  53  } __packed __aligned(4);
55c1528f9b97ff drivers/net/ethernet/sfc/selftest.c Edward Cree     2023-07-28  54  #define EFX_LOOPBACK_PAYLOAD_LEN	\
55c1528f9b97ff drivers/net/ethernet/sfc/selftest.c Edward Cree     2023-07-28  55  		sizeof_field(struct efx_loopback_payload, packet)
3273c2e8c66a21 drivers/net/sfc/selftest.c          Ben Hutchings   2008-05-07  56  

:::::: The code at line 48 was first introduced by commit
:::::: 3273c2e8c66a21ae1c53b0c730ee937c6efde7e2 [netdrvr] sfc: sfc: Add self-test support

:::::: TO: Ben Hutchings <bhutchings@solarflare.com>
:::::: CC: Jeff Garzik <jgarzik@redhat.com>

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