perf subcmd: avoid crash in exclude_cmds when excludes is empty

When cross-compiling the perf tool for ARM64, `perf help` may crash
with the following assertion failure:

  help.c:122: exclude_cmds: Assertion `cmds->names[ci] == NULL' failed.

This happens when the perf binary is not named exactly "perf" or when
multiple "perf-*" binaries exist in the same directory. In such cases,
the `excludes` command list can be empty, which leads to the final
assertion in exclude_cmds() being triggered.

Add a simple guard at the beginning of exclude_cmds() to return early
if excludes->cnt is zero, preventing the crash.

Signed-off-by: hupu <[email protected]>
Reported-by: Guilherme Amadio <[email protected]>
Reviewed-by: Namhyung Kim <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Namhyung Kim <[email protected]>

0 files changed, 0 insertions, 0 deletions