Re: [Crash-utility] [RFC PATCH 08/15] Support "mod -d|-D" options

On Fri, Jun 2, 2023 at 10:18 AM HAGIO KAZUHITO(萩尾 一仁) <k-hagio-ab(a)nec.com&gt; wrote: > On 2023/05/30 21:30, lijiang wrote: >> On Mon, May 29, 2023 at 9:03 AM HAGIO KAZUHITO(萩尾 一仁) < > k-hagio-ab(a)nec.com&gt; >> wrote: >> >>>> >>>> + for (j = MOD_TEXT; j < >>>>> MOD_MEM_NUM_TYPES; j++) { >>>>> + lm->load_symtable[j] = >>>>> NULL; >>>>> + lm->load_symend[j] = >>> NULL; >>>>> + } >>>>> + } else { /* somehow this function runs >>> for >>>>> unloaded modules */ >>>>> >>>> >>>> Could you please explain why it may get into the "else" code path? And >>> why >>>> do we need to handle this situation for now? But not needed before the >>>> module memory changes. >>> >>> This path is used by "mod -d|-D" and reinit_modules() for unloaded > modules. >>> >>> The old procedure always does the cleanup and reinstall of the hash >>> entries, so kept it as it is. >>> >> >> I tried to add some debug information in the above code path, but did not >> observe any output(via the mod -d/-D). It's strange. > > With this change, > > --- a/symbols.c > +++ b/symbols.c > @@ -13951,6 +13951,7 @@ delete_load_module(ulong base_addr) > lm->load_symend[j] = NULL; > } > } else { /* somehow this function runs > for unloaded modules */ > + fprintf(fp, "in the else block > (-D)\n"); > for (j = MOD_TEXT; j < > MOD_MEM_NUM_TYPES; j++) { > if (!lm->symtable[j]) > continue; > @@ -14016,6 +14017,7 @@ delete_load_module(ulong base_addr) > lm->load_symend[j] = NULL; > } > } else { /* somehow this function runs > for unloaded modules */ > + fprintf(fp, "in the else block > (-d)\n"); > for (j = MOD_TEXT; j < > MOD_MEM_NUM_TYPES; j++) { > if (!lm->symtable[j]) > continue; > > These should be printed: > > crash-6.4> mod -s dm_mod > MODULE NAME TEXT_BASE SIZE OBJECT > FILE > ffffffffc042fd00 dm_mod ffffffffc0418000 237568 > dm-mod.ko > crash-6.4> mod -d dm_mod > crash-6.4> mod -d dm_mod > Ah, I know why I did not see any output(via the mod -d/-D), because I only ran the "mod -d/-D" *once*. And for now I can see the debug information after running the mod -d/-D *twice*.