[kbuild-all] Re: [linux-next:master 2296/2770] kernel/bpf/helpers.c:713:43: warning: Uninitialized variable: bufs [uninitvar]

On Fri, May 14, 2021 at 8:37 AM kernel test robot <lkp(a)intel.com&gt; wrote: > cppcheck possible warnings: (new ones prefixed by >>, may not real problems) > > >> kernel/bpf/helpers.c:713:43: warning: Uninitialized variable: bufs [uninitvar] > if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(bufs->tmp_bufs))) { > ^ I don't think this is a real problem. bufs is not actually dereferenced, it is only used to give the type information to a sizeof. This is only evaluated at compilation time. If this matters, I guess we could silent this cppcheck warning with something like the following patch. Alexei, what do you think ? --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -697,8 +697,9 @@ static int bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype, #define MAX_PRINTF_BUF_LEN 512 /* Support executing three nested bprintf helper calls on a given CPU */ +#define MAX_PRINTF_NEST_LEVEL 3 struct bpf_bprintf_buffers { - char tmp_bufs[3][MAX_PRINTF_BUF_LEN]; + char tmp_bufs[MAX_PRINTF_NEST_LEVEL][MAX_PRINTF_BUF_LEN]; }; static DEFINE_PER_CPU(struct bpf_bprintf_buffers, bpf_bprintf_bufs); static DEFINE_PER_CPU(int, bpf_bprintf_nest_level); @@ -710,7 +711,7 @@ static int try_get_fmt_tmp_buf(char **tmp_buf) preempt_disable(); nest_level = this_cpu_inc_return(bpf_bprintf_nest_level); - if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(bufs->tmp_bufs))) { + if (WARN_ON_ONCE(nest_level > MAX_PRINTF_NEST_LEVEL)) {