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pahole: Use 32-bit integers for type ID iterations within CU 

Existing code base assumes that single CU doesn't have more than 65535
types per each CU, which might be a reasonable assumption for DWARF
data. With BTF, though, all we get is single, potentially huge, CU which
can easily have more than 65k types. For example, this is the case for
allyesconfig version of Linux kernel, which has >200k types.

Due to this assumption, libdwarves and other parts of pahole are using
16-bit counters to iterate over entities within CU. This can cause
infinite loops when iterating BTF data, if there are more than 65535
types. This patch changes non-public variables to use 32-bit integers,
where appropriate.

This still leads to invalid reported data when using BTF loader (due to using
(X & 0xFFFF) type ID, instead of X, when X > 65535) and loading huge files,
but at least it's not stuck in an infinite loop anymore.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: dwarves@vger.kernel.org
[ Removed non type ID conversions, for instance for the kind of tag, like in type->namespace.tag.tag, that can remain a uint16_t ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Andrii Nakryiko 2019-03-06 16:23:21 -08:00 committed by Arnaldo Carvalho de Melo
parent 3bd8da5202
commit 3526ebebd3
4 changed files with 25 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
btf_loader.c
View File

@ -45,7 +45,7 @@ static void *tag__alloc(const size_t size)
return tag;
}
static int btf_elf__load_ftype(struct btf_elf *btfe, struct ftype *proto, uint16_t tag,
static int btf_elf__load_ftype(struct btf_elf *btfe, struct ftype *proto, uint32_t tag,
uint32_t type, uint16_t vlen, struct btf_param *args, long id)
{
int i;
@ -100,7 +100,7 @@ static struct base_type *base_type__new(strings_t name, uint32_t attrs,
return bt;
}
static void type__init(struct type *type, uint16_t tag,
static void type__init(struct type *type, uint32_t tag,
strings_t name, size_t size)
{
INIT_LIST_HEAD(&type->node);

14
dwarves.c
View File

@ -349,7 +349,7 @@ reevaluate:
static void cu__find_class_holes(struct cu *cu)
{
uint16_t id;
uint32_t id;
struct class *pos;
cu__for_each_struct(cu, id, pos)
@ -566,7 +566,7 @@ struct tag *cu__type(const struct cu *cu, const uint16_t id)
struct tag *cu__find_first_typedef_of_type(const struct cu *cu,
const uint16_t type)
{
uint16_t id;
uint32_t id;
struct tag *pos;
if (cu == NULL || type == 0)
@ -582,7 +582,7 @@ struct tag *cu__find_first_typedef_of_type(const struct cu *cu,
struct tag *cu__find_base_type_by_name(const struct cu *cu,
const char *name, uint16_t *idp)
{
uint16_t id;
uint32_t id;
struct tag *pos;
if (cu == NULL || name == NULL)
@ -611,7 +611,7 @@ struct tag *cu__find_base_type_by_sname_and_size(const struct cu *cu,
uint16_t bit_size,
uint16_t *idp)
{
uint16_t id;
uint32_t id;
struct tag *pos;
if (sname == 0)
@ -638,7 +638,7 @@ struct tag *cu__find_enumeration_by_sname_and_size(const struct cu *cu,
uint16_t bit_size,
uint16_t *idp)
{
uint16_t id;
uint32_t id;
struct tag *pos;
if (sname == 0)
@ -663,7 +663,7 @@ struct tag *cu__find_enumeration_by_sname_and_size(const struct cu *cu,
struct tag *cu__find_struct_by_sname(const struct cu *cu, strings_t sname,
const int include_decls, uint16_t *idp)
{
uint16_t id;
uint32_t id;
struct tag *pos;
if (sname == 0)
@ -699,7 +699,7 @@ static struct tag *__cu__find_struct_by_name(const struct cu *cu, const char *na
if (cu == NULL || name == NULL)
return NULL;
uint16_t id;
uint32_t id;
struct tag *pos;
cu__for_each_type(cu, id, pos) {
struct type *type;

2
dwarves_fprintf.c
View File

@ -163,7 +163,7 @@ static const char *tag__accessibility(const struct tag *tag)
return NULL;
}
static size_t __tag__id_not_found_snprintf(char *bf, size_t len, uint16_t id,
static size_t __tag__id_not_found_snprintf(char *bf, size_t len, uint32_t id,
const char *fn, int line)
{
return snprintf(bf, len, "<ERROR(%s:%d): %#llx not found!>", fn, line,

30
pahole.c
View File

@ -156,7 +156,7 @@ static void nr_definitions_formatter(struct structure *st)
}
static void nr_members_formatter(struct class *class,
struct cu *cu, uint16_t id __unused)
struct cu *cu, uint32_t id __unused)
{
printf("%s%c%u\n", class__name(class, cu), separator,
class__nr_members(class));
@ -168,26 +168,26 @@ static void nr_methods_formatter(struct structure *st)
}
static void size_formatter(struct class *class,
struct cu *cu, uint16_t id __unused)
struct cu *cu, uint32_t id __unused)
{
printf("%s%c%d%c%u\n", class__name(class, cu), separator,
class__size(class), separator, class->nr_holes);
}
static void class_name_len_formatter(struct class *class, struct cu *cu,
uint16_t id __unused)
uint32_t id __unused)
{
const char *name = class__name(class, cu);
printf("%s%c%zd\n", name, separator, strlen(name));
}
static void class_name_formatter(struct class *class,
struct cu *cu, uint16_t id __unused)
struct cu *cu, uint32_t id __unused)
{
puts(class__name(class, cu));
}
static void class_formatter(struct class *class, struct cu *cu, uint16_t id)
static void class_formatter(struct class *class, struct cu *cu, uint32_t id)
{
struct tag *typedef_alias = NULL;
struct tag *tag = class__tag(class);
@ -224,7 +224,7 @@ static void class_formatter(struct class *class, struct cu *cu, uint16_t id)
putchar('\n');
}
static void print_packable_info(struct class *c, struct cu *cu, uint16_t id)
static void print_packable_info(struct class *c, struct cu *cu, uint32_t id)
{
const struct tag *t = class__tag(c);
const size_t orig_size = class__size(c);
@ -267,14 +267,14 @@ static void print_stats(void)
}
static struct class *class__filter(struct class *class, struct cu *cu,
uint16_t tag_id);
uint32_t tag_id);
static void (*formatter)(struct class *class,
struct cu *cu, uint16_t id) = class_formatter;
struct cu *cu, uint32_t id) = class_formatter;
static void print_classes(struct cu *cu)
{
uint16_t id;
uint32_t id;
struct class *pos;
cu__for_each_struct_or_union(cu, id, pos) {
@ -352,7 +352,7 @@ static int class__packable(struct class *class, struct cu *cu)
}
static struct class *class__filter(struct class *class, struct cu *cu,
uint16_t tag_id)
uint32_t tag_id)
{
struct tag *tag = class__tag(class);
const char *name;
@ -608,7 +608,7 @@ static void cu_fixup_word_size_iterator(struct cu *cu)
original_word_size = cu->addr_size;
cu->addr_size = word_size;
uint16_t id;
uint32_t id;
struct tag *pos;
cu__for_each_type(cu, id, pos)
tag__fixup_word_size(pos, cu);
@ -659,11 +659,11 @@ static void cu__account_nr_methods(struct cu *cu)
static char tab[128];
static void print_structs_with_pointer_to(const struct cu *cu, uint16_t type)
static void print_structs_with_pointer_to(const struct cu *cu, uint32_t type)
{
struct class *pos;
struct class_member *pos_member;
uint16_t id;
uint32_t id;
cu__for_each_struct(cu, id, pos) {
bool looked = false;
@ -702,10 +702,10 @@ static void print_structs_with_pointer_to(const struct cu *cu, uint16_t type)
}
}
static void print_containers(const struct cu *cu, uint16_t type, int ident)
static void print_containers(const struct cu *cu, uint32_t type, int ident)
{
struct class *pos;
uint16_t id;
uint32_t id;
cu__for_each_struct(cu, id, pos) {
if (pos->type.namespace.name == 0)