libbpf: turn relo_core->sym_off unsigned

The symbols' relocation offsets in BPF are stored in an int field,
but cannot actually be negative. When in the next patch libbpf relocates
globals to the end of the arena, it is also possible to have valid
offsets > 2GiB that are used to calculate the final relo offsets.
Avoid accidentally interpreting large offsets as negative by turning
the sym_off field unsigned.

Signed-off-by: Emil Tsalapatis <[email protected]>
Acked-by: Eduard Zingerman <[email protected]>

Author: etsal

tools/lib/bpf/libbpf.c

@@ -380,7 +380,7 @@ struct reloc_desc {
 		const struct bpf_core_relo *core_relo; /* used when type == RELO_CORE */
 		struct {
 			int map_idx;
-			int sym_off;
+			unsigned int sym_off;
 			/*
 			 * The following two fields can be unionized, as the
 			 * ext_idx field is used for extern symbols, and the
@@ -763,7 +763,7 @@ struct bpf_object {
 
 	struct {
 		struct bpf_program *prog;
-		int sym_off;
+		unsigned int sym_off;
 		int fd;
 	} *jumptable_maps;
 	size_t jumptable_map_cnt;