On 2023/05/26 19:37, lijiang wrote:
> On Thu, May 11, 2023 at 12:35 PM HAGIO KAZUHITO(萩尾 一仁) <k-hagio-ab@xxxxxxx>
> wrote:
>
>> Support percpu symbols for "sym" options and etc.
>>
>> crash> mod -s kvm_intel
>> MODULE NAME BASE SIZE OBJECT
>> FILE
>> ffffffffc0b1b480 kvm_intel ffffffffc0d0c000 372736
>> /home/kernel/linux-next-next-20230310/arch/x86/kvm/kvm-intel.ko
>> crash> sym -m kvm_intel | head
>> 35020 MODULE PERCPU START: kvm_intel
>> 35020 (d) loaded_vmcss_on_cpu
>> 35030 (d) vmxarea
>> 35038 (D) current_vmcs
>> 35040 (d) wakeup_vcpus_on_cpu_lock
>> 35050 (d) wakeup_vcpus_on_cpu
>> 35060 MODULE PERCPU END: kvm_intel
>> ffffffffc0aae000 MODULE RO_AFTER_INIT START: kvm_intel
>> ffffffffc0ab1720 (D) vmx_capability
>> ffffffffc0ab1740 (D) vmcs_config
>> crash> sym vmxarea
>> 35030 (d) vmxarea [kvm_intel]
>>
>> Signed-off-by: Kazuhito Hagio <k-hagio-ab@xxxxxxx>
>> ---
>> symbols.c | 82 ++++++++++++++++++++++++++-----------------------------
>> 1 file changed, 38 insertions(+), 44 deletions(-)
>>
>> diff --git a/symbols.c b/symbols.c
>> index 8343081f51f7..40e992e9ee12 100644
>> --- a/symbols.c
>> +++ b/symbols.c
>> @@ -1302,7 +1302,7 @@ symname_hash_search(struct syment *table[], char
>> *name)
>> static void
>> module_symbol_dump(char *module)
>> {
>> - int i, j, m, start, percpu_syms;
>> + int i, j, m;
>> struct syment *sp, *sp_end;
>> struct load_module *lm;
>> const char *p1, *p2;
>> @@ -1319,6 +1319,19 @@ module_symbol_dump(char *module)
>> if (received_SIGINT() || output_closed())
>> return;
>>
>> + /* The percpu area isn't included in any module memory
>> area. */
>>
>
> Could you please point out where the percpu area is? That can help us to
> understand easily. For example:
>
> The percpu area is included in the .data..percpu section, and not in any
> module memory areas.
> # objdump -h vmlinux|grep percpu
> 19 .data..percpu 00035000 0000000000000000 0000000003240000 02600000
> 2**12
ok thanks, will improve the comment.
(Some of my comments were just memos, intended to improve or remove them.)
Thanks,
Kazu
>
> + if (MODULE_PERCPU_SYMS_LOADED(lm)) {
>> + p1 = "MODULE PERCPU START";
>> + p2 = lm->mod_name;
>> + fprintf(fp, "%lx %s: %s\n", lm->mod_percpu, p1,
>> p2);
>> +
>> + dump_percpu_symbols(lm);
>> +
>> + p1 = "MODULE PERCPU END";
>> + fprintf(fp, "%lx %s: %s\n",
>> + lm->mod_percpu + lm->mod_percpu_size, p1,
>> p2);
>> + }
>> +
>> for (m = 0; m < lm->nr_mems; m++) {
>> j = lm->address_order[m];
>>
>> @@ -1327,21 +1340,8 @@ module_symbol_dump(char *module)
>>
>> sp = lm->symtable[j];
>> sp_end = lm->symend[j];
>> - percpu_syms = 0;
>>
>> - for (start = FALSE; sp <= sp_end; sp++) {
>> - /* TODO
>> - if (IN_MODULE_PERCPU(sp->value, lm)) {
>> - if (percpu_syms == DISPLAYED)
>> - continue;
>> - if (!start) {
>> - percpu_syms = TBD;
>> - continue;
>> - }
>> - dump_percpu_symbols(lm);
>> - percpu_syms = DISPLAYED;
>> - }
>> - */
>> + for ( ; sp <= sp_end; sp++) {
>> if (MODULE_PSEUDO_SYMBOL(sp)) {
>> if (MODULE_SECTION_START(sp)) {
>> p1 = sp->name +
>> strlen("_MODULE_SECTION_START ");
>> @@ -1352,30 +1352,15 @@ module_symbol_dump(char *module)
>> } else if (STRNEQ(sp->name,
>> module_start_tags[j])) {
>> p1 = module_start_strs[j];
>> p2 = sp->name +
>> strlen(module_start_tags[j]);
>> - start = TRUE;
>> } else if (STRNEQ(sp->name,
>> module_end_tags[j])) {
>> p1 = module_end_strs[j];
>> p2 = sp->name +
>> strlen(module_end_tags[j]);
>> - /* TODO
>> - if
>> (MODULE_PERCPU_SYMS_LOADED(lm) &&
>> - !percpu_syms) {
>> -
>> dump_percpu_symbols(lm);
>> - percpu_syms =
>> DISPLAYED;
>> - }
>> - */
>> } else {
>> p1 = "unknown tag";
>> p2 = sp->name;
>> }
>>
>> fprintf(fp, "%lx %s: %s\n",
>> sp->value, p1, p2);
>> -
>> - /* TODO
>> - if (percpu_syms == TBD) {
>> - dump_percpu_symbols(lm);
>> - percpu_syms = DISPLAYED;
>> - }
>> - */
>> } else
>> show_symbol(sp, 0, SHOW_RADIX());
>> }
>> @@ -1497,8 +1482,14 @@ dump_percpu_symbols(struct load_module *lm)
>> struct syment *sp, *sp_end;
>>
>> if (MODULE_PERCPU_SYMS_LOADED(lm)) {
>> - sp = lm->mod_symtable;
>> - sp_end = lm->mod_symend;
>> + if (MODULE_MEMORY()) {
>> + /* The lm should have mod_load_symtable. */
>> + sp = lm->mod_load_symtable;
>> + sp_end = lm->mod_load_symend;
>> + } else {
>> + sp = lm->mod_symtable;
>> + sp_end = lm->mod_symend;
>> + }
>> for ( ; sp <= sp_end; sp++) {
>> if (IN_MODULE_PERCPU(sp->value, lm))
>> show_symbol(sp, 0, SHOW_RADIX());
>> @@ -2314,6 +2305,11 @@ store_module_symbols_v3(ulong total, int
>> mods_installed)
>> if (symbol_query("__insmod_", NULL, NULL))
>> st->flags |= INSMOD_BUILTIN;
>>
>> + if (CRASHDEBUG(2)) {
>> + for (sp = st->ext_module_symtable; sp <
>> st->ext_module_symend; sp++)
>> + fprintf(fp, "%16lx %s\n", sp->value, sp->name);
>> + }
>> +
>> if (mcnt > total)
>> error(FATAL, "store_module_symbols_v3: total: %ld mcnt:
>> %d\n", total, mcnt);
>> }
>> @@ -12128,6 +12124,13 @@ store_section_data(struct load_module *lm, bfd
>> *bfd, asection *section)
>> lm->mod_section_data[i].section = section;
>> lm->mod_section_data[i].priority = prio;
>> lm->mod_section_data[i].flags = section->flags & ~SEC_FOUND;
>> + lm->mod_section_data[i].size = bfd_section_size(section);
>> + lm->mod_section_data[i].offset = 0;
>> + lm->mod_section_data[i].addr = 0;
>>
>
> The variable mod_section_data should be initialized once the memory is
> allocated successfully. Here it should set useful values to the member
> variables, unless it needs to set the zero for some of the member variables
> every time.
>
> Thanks
> Lianbo
>
> + if (strlen(name) < MAX_MOD_SEC_NAME)
>> + strcpy(lm->mod_section_data[i].name, name);
>> + else
>> + strncpy(lm->mod_section_data[i].name, name,
>> MAX_MOD_SEC_NAME-1);
>> /*
>> * The percpu section isn't included in kallsyms or module_core
>> area.
>> */
>> @@ -12135,14 +12138,8 @@ store_section_data(struct load_module *lm, bfd
>> *bfd, asection *section)
>> (STREQ(name,".data.percpu") || STREQ(name, ".data..percpu"))) {
>> lm->mod_percpu_size = bfd_section_size(section);
>> lm->mod_section_data[i].flags |= SEC_FOUND;
>> + lm->mod_section_data[i].addr = lm->mod_percpu;
>> }
>> - lm->mod_section_data[i].size = bfd_section_size(section);
>> - lm->mod_section_data[i].offset = 0;
>> - lm->mod_section_data[i].addr = 0;
>> - if (strlen(name) < MAX_MOD_SEC_NAME)
>> - strcpy(lm->mod_section_data[i].name, name);
>> - else
>> - strncpy(lm->mod_section_data[i].name, name,
>> MAX_MOD_SEC_NAME-1);
>> lm->mod_sections += 1;
>> }
>>
>> @@ -13546,11 +13543,8 @@ append_section_symbols:
>> }
>> lm->symtable = lm->load_symtable;
>> lm->symend = lm->load_symend;
>> - for (i = MOD_TEXT; i < MOD_MEM_NUM_TYPES; i++) {
>> - if (!lm->symtable[i])
>> - continue;
>> - mod_symtable_hash_install_range(lm->symtable[i],
>> lm->symend[i]);
>> - }
>> + /* percpu symbols is out of the ranges.. */
>> + mod_symtable_hash_install_range(lm->mod_load_symtable,
>> lm->mod_load_symend);
>> } else {
>> mod_symtable_hash_remove_range(lm->mod_symtable,
>> lm->mod_symend);
>> lm->mod_symtable = lm->mod_load_symtable;
>> --
>> 2.31.1
>>
>>
--
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