perf bpf augmented_raw_syscalls: Add an assert to make sure sizeof(augmented_arg...

Similar to what was done in the previous cset for sizeof(saddr), we need
to make sure sizeof(augmented_arg->value) is a power of two to do bounds
checking using &=:

  augmented_len &= sizeof(augmented_arg->value) - 1;

Suggested-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/lkml/ZONrPo0NSqdbXiGx@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c b/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c
index 43549b6..90ce22f 100644 (file)
--- a/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c
+++ b/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c
@@ -160,6 +160,7 @@ unsigned int augmented_arg__read_str(struct augmented_arg *augmented_arg, const
         */
        if (string_len > 0) {
                augmented_len -= sizeof(augmented_arg->value) - string_len;
+               _Static_assert(is_power_of_2(sizeof(augmented_arg->value)), "sizeof(augmented_arg->value) needs to be a power of two");
                augmented_len &= sizeof(augmented_arg->value) - 1;
                augmented_arg->size = string_len;
        } else {