On 25/08/18 10:57AM, Dan Carpenter wrote: > Hi Anton, > > kernel test robot noticed the following build warnings: > > url: https://github.com/intel-lab-lkp/linux/commits/Anton-Protopopov/bpf-fix-the-return-value-of-push_stack/20250817-020411 > base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master > patch link: https://lore.kernel.org/r/20250816180631.952085-9-a.s.protopopov%40gmail.com > patch subject: [PATCH v1 bpf-next 08/11] bpf, x86: add support for indirect jumps > config: x86_64-randconfig-161-20250818 (https://download.01.org/0day-ci/archive/20250818/202508180805.aUCPtTuQ-lkp@xxxxxxxxx/config) > compiler: gcc-12 (Debian 12.2.0-14+deb12u1) 12.2.0 > > If you fix the issue in a separate patch/commit (i.e. not just a new version of > the same patch/commit), kindly add following tags > | Reported-by: kernel test robot <lkp@xxxxxxxxx> > | Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> > | Closes: https://lore.kernel.org/r/202508180805.aUCPtTuQ-lkp@xxxxxxxxx/ > > smatch warnings: > kernel/bpf/verifier.c:25013 compute_scc() warn: unsigned 'succ_cnt' is never less than zero. > > vim +/w +25013 kernel/bpf/verifier.c > 24891 static int compute_scc(struct bpf_verifier_env *env) > 24892 { > 24893 const u32 NOT_ON_STACK = U32_MAX; > 24894 > 24895 struct bpf_insn_aux_data *aux = env->insn_aux_data; > 24896 const u32 insn_cnt = env->prog->len; > 24897 int stack_sz, dfs_sz, err = 0; > 24898 u32 *stack, *pre, *low, *dfs; > 24899 u32 succ_cnt, i, j, t, w; > ^^^^^^^^^^^^ > > 24900 u32 next_preorder_num; > 24901 u32 next_scc_id; > 24902 bool assign_scc; > 24903 > 24904 next_preorder_num = 1; > 24905 next_scc_id = 1; > 24906 /* > > [ snip ] > > 25008 next_preorder_num++; > 25009 stack[stack_sz++] = w; > 25010 } > 25011 /* Visit 'w' successors */ > 25012 succ_cnt = insn_successors(env, env->prog, w, &succ); > 25013 if (succ_cnt < 0) { > ^^^^^^^^^^^^ > unsigned can't be negative. Thanks! Fixed, will squash into v2. > 25014 err = succ_cnt; > 25015 goto exit; > 25016 > 25017 } > 25018 for (j = 0; j < succ_cnt; ++j) { > 25019 if (pre[succ[j]]) { > 25020 low[w] = min(low[w], low[succ[j]]); > > -- > 0-DAY CI Kernel Test Service > https://github.com/intel/lkp-tests/wiki >
