Hi Tobias, I love your patch! Perhaps something to improve: [auto build test WARNING on bpf-next/master] url: https://github.com/0day-ci/linux/commits/Tobias-Klauser/bpf-x86-Factor-co... base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master config: x86_64-randconfig-s022-20200710 (attached as .config) compiler: gcc-9 (Debian 9.3.0-14) 9.3.0 reproduce: # apt-get install sparse # sparse version: v0.6.2-37-gc9676a3b-dirty # save the attached .config to linux build tree make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; sparse warnings: (new ones prefixed by >>) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (e58948 becomes 48) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (e58948 becomes 8948) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (ec8148 becomes 48) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (ec8148 becomes 8148) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (5541 becomes 41) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (5641 becomes 41) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (5741 becomes 41) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (d289 becomes 89) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (1c5639 becomes 5639) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (2b76 becomes 76) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (858b becomes 8b) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (fffffddc becomes dc) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (20f883 becomes 83) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (20f883 becomes f883) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (2077 becomes 77) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (1c083 becomes 83) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (1c083 becomes c083) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (8589 becomes 89) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (fffffddc becomes dc) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (d6848b48 becomes 48) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (d6848b48 becomes 8b48) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (190 becomes 90) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (c08548 becomes 48) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (c08548 becomes 8548) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (a74 becomes 74) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (30408b48 becomes 48) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (30408b48 becomes 8b48) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (19c08348 becomes 48) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (19c08348 becomes 8348) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (e0ff becomes ff) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (858b becomes 8b) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (fffffddc becomes dc) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (20f883 becomes 83) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (20f883 becomes f883) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (e77 becomes 77) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (1c083 becomes 83) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (1c083 becomes c083) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (8589 becomes 89) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (fffffddc becomes dc) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (8966 becomes 66) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (c3c749 becomes 49) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (c3c749 becomes c749) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (d231 becomes 31) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (f3f749 becomes 49) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (f3f749 becomes f749) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (f3f741 becomes 41) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (f3f741 becomes f741) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (d38949 becomes 49) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (d38949 becomes 8949) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (c38949 becomes 49) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (c38949 becomes 8949) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (b70f45 becomes 45) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (b70f45 becomes f45) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (b70f becomes f) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (f41 becomes 41) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (b70f45 becomes 45) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (b70f45 becomes f45) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (b70f becomes f) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (c641 becomes 41) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (c74166 becomes 66) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (c74166 becomes 4166) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (c766 becomes 66) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (c741 becomes 41) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (1f0 becomes f0) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (5f41 becomes 41) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (5e41 becomes 41) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (5d41 becomes 41) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (f87d8348 becomes 48) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (f87d8348 becomes 8348) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (e58948 becomes 48) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (e58948 becomes 8948) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (8c48348 becomes 48) arch/x86/net/bpf_jit.h:15:31: sparse: sparse: cast truncates bits from constant value (8c48348 becomes 8348) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (e2ff becomes ff) arch/x86/net/bpf_jit.h:13:24: sparse: sparse: cast truncates bits from constant value (8f0f becomes f) vim +13 arch/x86/net/bpf_jit.h 9 10 static inline u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len) 11 { 12 if (len == 1) 14 else if (len == 2) 15 *(u16 *)ptr = bytes; 16 else { 17 *(u32 *)ptr = bytes; 18 barrier(); 19 } 20 return ptr + len; 21 } 22 --- 0-DAY CI Kernel Test Service, Intel Corporation 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