{ "raw_tracepoint_writable: reject variable offset", .insns = { /* r6 is our tp buffer */ BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0), BPF_LD_MAP_FD(BPF_REG_1, 0), /* move the key (== 0) to r10-8 */ BPF_MOV32_IMM(BPF_REG_0, 0), BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 0), /* lookup in the map */ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), /* exit clean if null */ BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1), BPF_EXIT_INSN(), /* shift the buffer pointer to a variable location */ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 0), BPF_ALU64_REG(BPF_ADD, BPF_REG_6, BPF_REG_0), /* clobber whatever's there */ BPF_MOV64_IMM(BPF_REG_7, 4242), BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_7, 0), BPF_MOV64_IMM(BPF_REG_0, 0), BPF_EXIT_INSN(), }, .fixup_map_hash_8b = { 1, }, .prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE, .errstr = "R6 invalid variable buffer offset: off=0, var_off=(0x0; 0xffffffff)", },