Recommit "Allow to ask for deeper callers for leak reports using

malloc options"

Now only enabled for platforms where it's know to work and written
as a inline functions instead of a macro.

2 files changed, 71 insertions, 12 deletions

diff --git a/src/lib/libc/stdlib/malloc.3 b/src/lib/libc/stdlib/malloc.3
index 79e85f39ee..88a8264da5 100644
--- a/src/lib/libc/stdlib/malloc.3
+++ b/src/lib/libc/stdlib/malloc.3
@@ -30,9 +30,9 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.\"     $OpenBSD: malloc.3,v 1.135 2023/06/23 05:26:45 otto Exp $
+.\"     $OpenBSD: malloc.3,v 1.136 2023/06/30 06:24:58 otto Exp $
 .\"
-.Dd $Mdocdate: June 23 2023 $
+.Dd $Mdocdate: June 30 2023 $
 .Dt MALLOC 3
 .Os
 .Sh NAME
@@ -294,6 +294,17 @@ To record the dump:
 To view the leak report:
 .Pp
 .Dl $ kdump -u malloc ...
+.Pp
+By default, the immediate caller of a
+.Nm
+function will be recorded.
+Use malloc options
+.Cm 2
+or
+.Cm 3
+to record the caller one or two stack frames deeper instead.
+These malloc options imply
+.Cm D .
 .It Cm F
 .Dq Freecheck .
 Enable more extensive double free and use after free detection.
@@ -813,3 +824,14 @@ and
 .Fn realloc
 to avoid these problems on
 .Ox .
+.Pp
+The mechanism to record caller functions when using malloc options
+.Cm 2
+or
+.Cm 3
+is not guaranteed to work for all platforms, compilers or compilation
+options,
+and might even crash your program.
+Use
+.Em only
+for debugging purposes.
diff --git a/src/lib/libc/stdlib/malloc.c b/src/lib/libc/stdlib/malloc.c
index 34b2bb5e66..c09e1541e5 100644
--- a/src/lib/libc/stdlib/malloc.c
+++ b/src/lib/libc/stdlib/malloc.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: malloc.c,v 1.288 2023/06/23 05:26:45 otto Exp $       */
+/*      $OpenBSD: malloc.c,v 1.289 2023/06/30 06:24:58 otto Exp $       */
 /*
  * Copyright (c) 2008, 2010, 2011, 2016, 2023 Otto Moerbeek <otto@drijf.net>
  * Copyright (c) 2012 Matthew Dempsky <matthew@openbsd.org>
@@ -255,7 +255,37 @@ void malloc_dump(void);
 PROTO_NORMAL(malloc_dump);
 static void malloc_exit(void);
 #endif
-#define CALLER  (DO_STATS ? __builtin_return_address(0) : NULL)
+
+#if defined(__aarch64__) || \
+        defined(__amd64__) || \
+        defined(__arm__)
+static inline void* caller(void)
+{
+        void *p;
+
+        switch (DO_STATS) {
+        case 0:
+        default:
+                return NULL;
+        case 1:
+                p = __builtin_return_address(0);
+                break;
+        case 2:
+                p = __builtin_return_address(1);
+                break;
+        case 3:
+                p = __builtin_return_address(2);
+                break;
+        }
+        return __builtin_extract_return_addr(p);
+}
+#else
+static inline void* caller(void)
+{
+        return DO_STATS == 0 ? NULL :
+            __builtin_extract_return_addr(__builtin_return_address(0));
+}
+#endif
 
 /* low bits of r->p determine size: 0 means >= page size and r->size holding
  * real size, otherwise low bits is the bucket + 1
@@ -365,8 +395,15 @@ omalloc_parseopt(char opt)
                 mopts.malloc_stats = 0;
                 break;
         case 'D':
+        case '1':
                 mopts.malloc_stats = 1;
                 break;
+        case '2':
+                mopts.malloc_stats = 2;
+                break;
+        case '3':
+                mopts.malloc_stats = 3;
+                break;
 #endif /* MALLOC_STATS */
         case 'f':
                 mopts.malloc_freecheck = 0;
@@ -1436,7 +1473,7 @@ malloc(size_t size)
         int saved_errno = errno;
 
         PROLOGUE(getpool(), "malloc")
-        r = omalloc(d, size, 0, CALLER);
+        r = omalloc(d, size, 0, caller());
         EPILOGUE()
         return r;
 }
@@ -1450,7 +1487,7 @@ malloc_conceal(size_t size)
         int saved_errno = errno;
 
         PROLOGUE(mopts.malloc_pool[0], "malloc_conceal")
-        r = omalloc(d, size, 0, CALLER);
+        r = omalloc(d, size, 0, caller());
         EPILOGUE()
         return r;
 }
@@ -1860,7 +1897,7 @@ realloc(void *ptr, size_t size)
         int saved_errno = errno;
 
         PROLOGUE(getpool(), "realloc")
-        r = orealloc(&d, ptr, size, CALLER);
+        r = orealloc(&d, ptr, size, caller());
         EPILOGUE()
         return r;
 }
@@ -1891,7 +1928,7 @@ calloc(size_t nmemb, size_t size)
         }
 
         size *= nmemb;
-        r = omalloc(d, size, 1, CALLER);
+        r = omalloc(d, size, 1, caller());
         EPILOGUE()
         return r;
 }
@@ -1916,7 +1953,7 @@ calloc_conceal(size_t nmemb, size_t size)
         }
 
         size *= nmemb;
-        r = omalloc(d, size, 1, CALLER);
+        r = omalloc(d, size, 1, caller());
         EPILOGUE()
         return r;
 }
@@ -2072,7 +2109,7 @@ recallocarray(void *ptr, size_t oldnmemb, size_t newnmemb, size_t size)
                 oldsize = oldnmemb * size;
         }
 
-        r = orecallocarray(&d, ptr, oldsize, newsize, CALLER);
+        r = orecallocarray(&d, ptr, oldsize, newsize, caller());
         EPILOGUE()
         return r;
 }
@@ -2204,7 +2241,7 @@ posix_memalign(void **memptr, size_t alignment, size_t size)
                 malloc_recurse(d);
                 goto err;
         }
-        r = omemalign(d, alignment, size, 0, CALLER);
+        r = omemalign(d, alignment, size, 0, caller());
         d->active--;
         _MALLOC_UNLOCK(d->mutex);
         if (r == NULL) {
@@ -2242,7 +2279,7 @@ aligned_alloc(size_t alignment, size_t size)
         }
 
         PROLOGUE(getpool(), "aligned_alloc")
-        r = omemalign(d, alignment, size, 0, CALLER);
+        r = omemalign(d, alignment, size, 0, caller());
         EPILOGUE()
         return r;
 }