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Merge pull request #684 from jpoimboe/find_local_syms-fix

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lookup: skip discarded symbols in local symbol comparison
This commit is contained in:
Josh Poimboeuf 2017-03-07 12:38:15 -06:00 committed by GitHub
commit 1308787995
1 changed files with 35 additions and 13 deletions
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48
kpatch-build/lookup.c
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@ -56,6 +56,7 @@ struct lookup_table {
struct object_symbol *obj_syms;
struct export_symbol *exp_syms;
struct object_symbol *local_syms;
int vmlinux;
};
#define for_each_obj_symbol(ndx, iter, table) \
@ -64,16 +65,31 @@ struct lookup_table {
#define for_each_exp_symbol(ndx, iter, table) \
for (ndx = 0, iter = table->exp_syms; ndx < table->exp_nr; ndx++, iter++)
static int discarded_sym(struct lookup_table *table,
struct sym_compare_type *sym)
{
if (table->vmlinux && sym->name &&
(!strncmp(sym->name, "__exitcall_", 11) ||
!strncmp(sym->name, "__brk_reservation_fn_", 21) ||
!strncmp(sym->name, "__func_stack_frame_non_standard_", 32)))
return 1;
return 0;
}
static void find_local_syms(struct lookup_table *table, char *hint,
struct sym_compare_type *locals)
struct sym_compare_type *child_locals)
{
struct object_symbol *sym, *file_sym;
int i, in_file = 0;
struct sym_compare_type *local_index;
struct sym_compare_type *child_sym;
if (!child_locals)
return;
for_each_obj_symbol(i, sym, table) {
if (sym->type == STT_FILE) {
if (in_file && !local_index->name) {
if (in_file && !child_sym->name) {
if (table->local_syms)
ERROR("find_local_syms for %s: found_dup", hint);
table->local_syms = file_sym;
@ -82,7 +98,7 @@ static void find_local_syms(struct lookup_table *table, char *hint,
if (!strcmp(hint, sym->name)) {
in_file = 1;
file_sym = sym;
local_index = locals;
child_sym = child_locals;
}
else
in_file = 0;
@ -95,15 +111,22 @@ static void find_local_syms(struct lookup_table *table, char *hint,
if (sym->bind != STB_LOCAL || (sym->type != STT_FUNC && sym->type != STT_OBJECT))
continue;
if (local_index->name &&
local_index->type == sym->type &&
!strcmp(local_index->name, sym->name))
local_index++;
/*
* Symbols which get discarded at link time are missing from
* the lookup table, so skip them.
*/
while (discarded_sym(table, child_sym))
child_sym++;
/* make sure the child symbol and parent symbol match */
if (child_sym->name && child_sym->type == sym->type &&
!strcmp(child_sym->name, sym->name))
child_sym++;
else
in_file = 0;
}
if (in_file && !local_index->name) {
if (in_file && !child_sym->name) {
if (table->local_syms)
ERROR("find_local_syms for %s: found_dup", hint);
table->local_syms = file_sym;
@ -263,12 +286,11 @@ struct lookup_table *lookup_open(char *obj_path, char *symvers_path,
ERROR("malloc table");
memset(table, 0, sizeof(*table));
table->vmlinux = !strcmp(basename(obj_path), "vmlinux");
obj_read(table, obj_path);
symvers_read(table, symvers_path);
table->local_syms = NULL;
if (locals)
find_local_syms(table, hint, locals);
find_local_syms(table, hint, locals);
return table;
}