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memleak: add backtrace to allocations.

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We use the tal notifiers to attach a `backtrace` object on every
allocation.

This also means moving backtrace_state from log.c into lightningd.c, so
we can hand it to memleak_init().

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
2017-12-15 20:48:54 +10:30
committed by Christian Decker
parent c956d9f5eb
commit dfc132b2fe
8 changed files with 111 additions and 20 deletions
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49
common/memleak.c
View File

@@ -1,3 +1,5 @@
#include <assert.h>
#include <backtrace.h>
#include <ccan/cast/cast.h>
#include <ccan/crypto/siphash24/siphash24.h>
#include <ccan/htable/htable.h>
@@ -5,6 +7,7 @@
#include <common/memleak.h>
#if DEVELOPER
static struct backtrace_state *backtrace_state;
static const void **notleaks;
void *notleak_(const void *ptr)
@@ -46,6 +49,11 @@ static void children_into_htable(const void *exclude,
for (i = tal_first(p); i; i = tal_next(i)) {
if (p == exclude)
continue;
/* Don't add backtrace objects. */
if (tal_name(i) && streq(tal_name(i), "backtrace"))
continue;
htable_add(memtable, hash_ptr(i, NULL), i);
children_into_htable(exclude, memtable, i);
}
@@ -108,7 +116,7 @@ static bool ptr_match(const void *candidate, void *ptr)
return candidate == ptr;
}
const void *memleak_get(struct htable *memtable)
const void *memleak_get(struct htable *memtable, const uintptr_t **backtrace)
{
struct htable_iter it;
const tal_t *i, *p;
@@ -128,12 +136,49 @@ const void *memleak_get(struct htable *memtable)
/* Delete all children */
remove_with_children(memtable, i);
/* Does it have a child called "backtrace"? */
for (*backtrace = tal_first(i);
*backtrace;
*backtrace = tal_next(*backtrace)) {
if (tal_name(*backtrace)
&& streq(tal_name(*backtrace), "backtrace"))
break;
}
return i;
}
void memleak_init(const tal_t *root)
static int append_bt(void *data, uintptr_t pc)
{
uintptr_t *bt = data;
if (bt[0] == 32)
return 1;
bt[bt[0]++] = pc;
return 0;
}
static void add_backtrace(tal_t *parent, enum tal_notify_type type UNNEEDED,
void *child)
{
uintptr_t *bt = tal_alloc_arr_(child, sizeof(uintptr_t), 32, true, true,
"backtrace");
/* First serves as counter. */
bt[0] = 1;
backtrace_simple(backtrace_state, 2, append_bt, NULL, bt);
tal_add_notifier(child, TAL_NOTIFY_ADD_CHILD, add_backtrace);
}
void memleak_init(const tal_t *root, struct backtrace_state *bstate)
{
assert(!notleaks);
backtrace_state = bstate;
notleaks = tal_arr(NULL, const void *, 0);
if (backtrace_state)
tal_add_notifier(root, TAL_NOTIFY_ADD_CHILD, add_backtrace);
}
void memleak_cleanup(void)

6
common/memleak.h
View File

@@ -2,6 +2,7 @@
#define LIGHTNING_COMMON_MEMLEAK_H
#include "config.h"
#include <ccan/tal/tal.h>
#include <inttypes.h>
#if HAVE_TYPEOF
#define memleak_typeof(var) typeof(var)
@@ -16,9 +17,10 @@
void *notleak_(const void *ptr);
struct htable;
struct backtrace_state;
/* Initialize memleak detection, with this as the root */
void memleak_init(const tal_t *root);
void memleak_init(const tal_t *root, struct backtrace_state *bstate);
/* Free memleak detection. */
void memleak_cleanup(void);
@@ -33,7 +35,7 @@ void memleak_remove_referenced(struct htable *memtable, const void *root);
void memleak_scan_region(struct htable *memtable, const void *p);
/* Get (and remove) a leak from memtable, or NULL */
const void *memleak_get(struct htable *memtable);
const void *memleak_get(struct htable *memtable, const uintptr_t **backtrace);
#else /* ... !DEVELOPER */
static inline void *notleak_(const void *ptr)