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{
"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)",
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
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