Hi. Thanks, this patch is very nice. On Mon, Jul 15, 2019 at 12:28 AM Denis Efremov <efremov@xxxxxxxxx> wrote: > > This patch adds a check to warn about static EXPORT_SYMBOL* functions > during the modpost. In most of the cases, a static symbol marked for > exporting is an odd combination that should be fixed either by deleting > the exporting mark or by removing the static attribute and adding the > appropriate declaration to headers. > > If this check will be considered useful, I will resend the patch with > review fixes. > > Currently, this check emits the warnings on the following symbols, most > of which are accepted to be fixed: > 1. "sas_wait_eh" [drivers/scsi/libsas/libsas] > Patch: https://lkml.org/lkml/2019/7/8/970 (accepted) > 2. "torture_onoff_cleanup" [kernel/torture] > "torture_shuffle_cleanup" [kernel/torture] > Patch: https://lkml.org/lkml/2019/7/4/411 (accepted) > 3. "LZ4HC_setExternalDict" [lib/lz4/lz4hc_compress] > Patch: https://lkml.org/lkml/2019/7/8/842 > 4. "drm_client_close" [drivers/gpu/drm/drm] > Patch: https://lkml.org/lkml/2019/7/3/758 (accepted) > 5. "gve_probe" [drivers/net/ethernet/google/gve/gve] > Patch: https://lkml.org/lkml/2019/7/14/65 > 6. "i2c_new_client_device" [vmlinux] > "i2c_new_dummy_device" [vmlinux] > Patch: https://lkml.org/lkml/2019/7/7/226 (fixed in a different patch) > 7. "ahci_em_messages" [drivers/ata/libahci] > Patch: https://lkml.org/lkml/2019/7/10/550 (reviwed) > 8. "ftrace_set_clr_event" [vmlinux] > Patch: https://lkml.org/lkml/2019/7/4/609 (reviwed) > 9. "rmi_2d_sensor_set_input_params" [drivers/input/rmi4/rmi_core] > Patch: https://lkml.org/lkml/2019/7/8/999 > 10. "empty_zero_page" [vmlinux] > 11. "phys_base" [vmlinux] > 12. "hypercall_page" [vmlinux] Could you drop the solved ones from the list? I still see the following at least, but I will apply this patch anyway. WARNING: "phys_base" [vmlinux] is a static EXPORT_SYMBOL symbol WARNING: "drm_client_close" [vmlinux] is a static EXPORT_SYMBOL symbol WARNING: "ahci_em_messages" [vmlinux] is a static EXPORT_SYMBOL_GPL symbol WARNING: "ftrace_set_clr_event" [vmlinux] is a static EXPORT_SYMBOL_GPL symbol WARNING: "empty_zero_page" [vmlinux] is a static EXPORT_SYMBOL symbol The code looks good to me. I commented on some minor style issues. > Similar commits: > 1. 54638c6eaf44 ("net: phy: make exported variables non-static") > 2. 98ef2046f28b ("mm: remove the exporting of totalram_pages") > 3. 73df167c819e ("s390/zcrypt: remove the exporting of ap_query_configuration") > 4. a57caf8c527f ("sunrpc/cache: remove the exporting of cache_seq_next") > 5. e4e4730698c9 ("crypto: skcipher - remove the exporting of skcipher_walk_next") > > Build time impact, allmodconfig, Dell XPS 15 9570 (measurements 3x): > $ make mrproper; make allmodconfig; time make -j12; \ > git checkout HEAD~1; \ > make mrproper; make allmodconfig; time make -j12 > 1. > (with patch) 17635,94s user 1895,54s system 1085% cpu 29:59,22 total > (w/o patch) 17275,42s user 1803,87s system 1112% cpu 28:35,66 total > 2. > (with patch) 17369,51s user 1763,28s system 1111% cpu 28:41,47 total > (w/o patch) 16880,50s user 1670,93s system 1113% cpu 27:46,56 total > 3. > (with patch) 17937,88s user 1842,53s system 1109% cpu 29:42,26 total > (w/o patch) 17267,55s user 1725,09s system 1111% cpu 28:28,17 total > > Thus, the current implementation adds approx. 1 min for allmodconfig. > However, it's possible to do the check in a more optimal way if it will > be considered useful. > > Also, this kind of check could be implemented as a separate script instead. > Here is the implementation: > https://gist.github.com/evdenis/bf2322d094f0c02c0f60fe0a225848b2 > > Signed-off-by: Denis Efremov <efremov@xxxxxxxxx> > @@ -199,8 +200,9 @@ static struct symbol *alloc_symbol(const char *name, unsigned int weak, > > memset(s, 0, sizeof(*s)); > strcpy(s->name, name); > - s->weak = weak; > - s->next = next; > + s->weak = weak; > + s->next = next; Could you drop this change? I do not think we need to align the '=' operator. > + s->is_static = 1; > return s; > } > > @@ -1980,6 +1982,21 @@ static void read_symbols(const char *modname) > handle_modversions(mod, &info, sym, symname); > handle_moddevtable(mod, &info, sym, symname); > } > + > + // check for static EXPORT_SYMBOL_* functions && global vars > + for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { > + unsigned char bind = ELF_ST_BIND(sym->st_info); > + unsigned char type = ELF_ST_TYPE(sym->st_info); > + > + if (type == STT_OBJECT || type == STT_FUNC) { > + struct symbol *s = > + find_symbol(remove_dot(info.strtab + sym->st_name)); > + > + if (s && (bind == STB_GLOBAL || bind == STB_WEAK)) > + s->is_static = 0; > + } > + } > + > if (!is_vmlinux(modname) || vmlinux_section_warnings) > check_sec_ref(mod, modname, &info); > > @@ -2425,6 +2442,7 @@ int main(int argc, char **argv) > char *dump_write = NULL, *files_source = NULL; > int opt; > int err; > + size_t n; > struct ext_sym_list *extsym_iter; > struct ext_sym_list *extsym_start = NULL; > > @@ -2520,6 +2538,19 @@ int main(int argc, char **argv) > if (sec_mismatch_count && sec_mismatch_fatal) > fatal("modpost: Section mismatches detected.\n" > "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n"); > + for (n = 0; n < SYMBOL_HASH_SIZE ; n++) { > + struct symbol *s = symbolhash[n]; > + > + while (s) { > + if (s->is_static) > + warn("\"%s\" [%s] is a static %s symbol\n", > + s->name, s->module->name, > + export_str(s->export)); Could you follow the checkpatch.pl suggestion? CHECK: Alignment should match open parenthesis #2550: FILE: scripts/mod/modpost.c:2550: + warn("\"%s\" [%s] is a static %s symbol\n", + s->name, s->module->name, (This file already has tons of checkpatch warnings, but I want to try my best to not add new ones.) Thanks. -- Best Regards Masahiro Yamada
