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-rw-r--r--libc/stdlib/malloc/heap_debug.c83
1 files changed, 67 insertions, 16 deletions
diff --git a/libc/stdlib/malloc/heap_debug.c b/libc/stdlib/malloc/heap_debug.c
index 1453a5a39..85ed15609 100644
--- a/libc/stdlib/malloc/heap_debug.c
+++ b/libc/stdlib/malloc/heap_debug.c
@@ -59,28 +59,79 @@ __heap_dump (struct heap *heap, const char *str)
}
+/* Output an error message to stderr, and exit. STR is printed with the
+ failure message. */
+static void
+__heap_check_failure (struct heap *heap, struct heap_free_area *fa,
+ const char *str, char *fmt, ...)
+{
+ va_list val;
+
+ if (str)
+ fprintf (stderr, "\nHEAP CHECK FAILURE %s: ", str);
+ else
+ fprintf (stderr, "\nHEAP CHECK FAILURE: ");
+
+ va_start (val, fmt);
+ vfprintf (stderr, fmt, val);
+ va_end (val);
+
+ fprintf (stderr, "\nheap dump:\n");
+ __heap_dump_freelist (heap);
+
+ exit (22);
+}
+
/* Do some consistency checks on HEAP. If they fail, output an error
message to stderr, and exit. STR is printed with the failure message. */
void
__heap_check (struct heap *heap, const char *str)
{
+ typedef unsigned long ul_t;
struct heap_free_area *fa, *prev;
+ struct heap_free_area *first_fa = heap->free_areas;
- for (prev = 0, fa = heap->free_areas; fa; prev = fa, fa = fa->next)
- if (fa->prev != prev)
- {
- if (str)
- fprintf (stderr, "\nHEAP CHECK FAILURE %s: ", str);
- else
- fprintf (stderr, "\nHEAP CHECK FAILURE: ");
-
- fprintf (stderr,
- " prev pointer corrupted: P=0x%lx should be 0x%lx\n",
- (long)fa->prev, (long)prev);
- fprintf (stderr, "\nheap:\n");
+ if (first_fa && first_fa->prev)
+ __heap_check_failure (heap, first_fa, str,
+"first free-area has non-zero prev pointer:\n\
+ first free-area = 0x%lx\n\
+ (0x%lx)->prev = 0x%lx\n",
+ (ul_t)first_fa,
+ (ul_t)first_fa, (ul_t)first_fa->prev);
- __heap_dump_freelist (heap);
-
- exit (22);
- }
+ for (prev = 0, fa = first_fa; fa; prev = fa, fa = fa->next)
+ {
+ if (((ul_t)HEAP_FREE_AREA_END (fa) & (HEAP_GRANULARITY - 1))
+ || (fa->size & (HEAP_GRANULARITY - 1)))
+ __heap_check_failure (heap, fa, str, "alignment error:\n\
+ (0x%lx)->start = 0x%lx\n\
+ (0x%lx)->size = 0x%lx\n",
+ (ul_t)fa,
+ (ul_t)HEAP_FREE_AREA_START (fa),
+ (ul_t)fa, fa->size);
+
+ if (fa->prev != prev)
+ __heap_check_failure (heap, fa, str, "prev pointer corrupted:\n\
+ (0x%lx)->next = 0x%lx\n\
+ (0x%lx)->prev = 0x%lx\n",
+ (ul_t)prev, (ul_t)prev->next,
+ (ul_t)fa, (ul_t)fa->prev);
+
+ if (prev)
+ {
+ ul_t start = (ul_t)HEAP_FREE_AREA_START (fa);
+ ul_t prev_end = (ul_t)HEAP_FREE_AREA_END (prev);
+
+ if (prev_end >= start)
+ __heap_check_failure (heap, fa, str,
+ "start %s with prev free-area end:\n\
+ (0x%lx)->prev = 0x%lx\n\
+ (0x%lx)->start = 0x%lx\n\
+ (0x%lx)->end = 0x%lx\n",
+ (prev_end == start ? "unmerged" : "overlaps"),
+ (ul_t)fa, (ul_t)prev,
+ (ul_t)fa, start,
+ (ul_t)prev, prev_end);
+ }
+ }
}