Allow to ask for deeper callers for leak reports using malloc options.

ok deraadt@

1 files changed, 24 insertions, 2 deletions

diff --git a/src/lib/libc/stdlib/malloc.3 b/src/lib/libc/stdlib/malloc.3
index d893626051..855f217c27 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 1.133 2023/06/04 06:58:33 otto Exp $
+.\"     $OpenBSD: malloc.3,v 1.134 2023/06/22 11:04:16 otto Exp $
 .\"
-.Dd $Mdocdate: June 4 2023 $
+.Dd $Mdocdate: June 22 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.