linux-stable/tools/bpf/bpftool
Yonghong Song 8af5014276 bpftool: Fix a clang compilation warning
With clang compiler:
  make -j60 LLVM=1 LLVM_IAS=1  <=== compile kernel
  # build selftests/bpf or bpftool
  make -j60 -C tools/testing/selftests/bpf LLVM=1 LLVM_IAS=1
  make -j60 -C tools/bpf/bpftool LLVM=1 LLVM_IAS=1
the following compilation warning showed up,
  net.c:160:37: warning: comparison of integers of different signs: '__u32' (aka 'unsigned int') and 'int' [-Wsign-compare]
                for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len);
                                                  ^~~~~~~~~~~~~~~~~
  .../tools/include/uapi/linux/netlink.h:99:24: note: expanded from macro 'NLMSG_OK'
                           (nlh)->nlmsg_len <= (len))
                           ~~~~~~~~~~~~~~~~ ^   ~~~

In this particular case, "len" is defined as "int" and (nlh)->nlmsg_len is "unsigned int".
The macro NLMSG_OK is defined as below in uapi/linux/netlink.h.
  #define NLMSG_OK(nlh,len) ((len) >= (int)sizeof(struct nlmsghdr) && \
                             (nlh)->nlmsg_len >= sizeof(struct nlmsghdr) && \
                             (nlh)->nlmsg_len <= (len))

The clang compiler complains the comparision "(nlh)->nlmsg_len <= (len))",
but in bpftool/net.c, it is already ensured that "len > 0" must be true.
So theoretically the compiler could deduce that comparison of
"(nlh)->nlmsg_len" and "len" is okay, but this really depends on compiler
internals. Let us add an explicit type conversion (from "int" to "unsigned int")
for "len" in NLMSG_OK to silence this warning right now.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210413153435.3029635-1-yhs@fb.com
2021-04-15 16:50:22 -07:00
..
bash-completion bpftool: Add gen object command to perform BPF static linking 2021-03-18 16:14:23 -07:00
Documentation bpftool: Add gen object command to perform BPF static linking 2021-03-18 16:14:23 -07:00
skeleton tools, bpftool: Remove two unused variables. 2020-10-29 15:23:18 +01:00
.gitignore tools/bpf: Remove bpf-helpers from bpftool docs 2021-03-04 18:39:45 -08:00
btf.c bpftool: Fix maybe-uninitialized warnings 2021-03-16 12:26:49 -07:00
btf_dumper.c tools/bpftool: Add BTF_KIND_FLOAT support 2021-03-04 17:58:15 -08:00
cfg.c tools, bpftool: Poison and replace kernel integer typedefs 2020-05-11 21:20:46 +02:00
cfg.h
cgroup.c tools, bpftool: Clean subcommand help messages 2020-06-01 14:38:18 -07:00
common.c sock_map: Introduce BPF_SK_SKB_VERDICT 2021-04-01 10:56:14 -07:00
feature.c bpf: Add kernel/modules BTF presence checks to bpftool feature command 2021-02-24 17:24:37 +01:00
gen.c bpftool: Add gen object command to perform BPF static linking 2021-03-18 16:14:23 -07:00
iter.c tools/bpf: Support new uapi for map element bpf iterator 2020-08-06 16:39:14 -07:00
jit_disasm.c tools/bpf/bpftool: Remove duplicate headers 2020-04-26 08:40:01 -07:00
json_writer.c bpftool: Support dumping metadata 2020-09-15 18:28:27 -07:00
json_writer.h bpftool: Support dumping metadata 2020-09-15 18:28:27 -07:00
link.c bpftool: Implement link_query for bpf iterators 2020-08-21 14:01:39 -07:00
main.c bpftool: Fix maybe-uninitialized warnings 2021-03-16 12:26:49 -07:00
main.h tools/bpftool: Add bpftool support for split BTF 2020-11-05 18:37:31 -08:00
Makefile New features: 2021-02-22 13:59:43 -08:00
map.c bpftool: Fix maybe-uninitialized warnings 2021-03-16 12:26:49 -07:00
map_perf_ring.c tools, bpftool: Poison and replace kernel integer typedefs 2020-05-11 21:20:46 +02:00
net.c bpftool: Fix a clang compilation warning 2021-04-15 16:50:22 -07:00
netlink_dumper.c bpftool: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
netlink_dumper.h tools: bpftool: dual license all files 2018-12-13 12:08:44 +01:00
perf.c tools, bpftool: Clean subcommand help messages 2020-06-01 14:38:18 -07:00
pids.c tools/bpftool: Fix PID fetching with a lot of results 2020-12-08 16:45:20 +01:00
prog.c sock_map: Introduce BPF_SK_SKB_VERDICT 2021-04-01 10:56:14 -07:00
struct_ops.c tools, bpftool: Clean subcommand help messages 2020-06-01 14:38:18 -07:00
tracelog.c tools: bpftool: add an option to prevent auto-mount of bpffs, tracefs 2018-12-18 14:47:17 +01:00
xlated_dumper.c bpftool: Print subprog address properly 2021-02-26 13:23:53 -08:00
xlated_dumper.h