diff --git a/ci.jsonnet b/ci.jsonnet
index 89d2695b4d..2c668164f3 100644
--- a/ci.jsonnet
+++ b/ci.jsonnet
@@ -274,7 +274,7 @@
         }),
         // tests with sandboxed backends for various modules (posix, sha3, compression, pyexpat, ...)
         "python-unittest-sandboxed": gpgate_ee + platform_spec(no_jobs) + platform_spec({
-            "linux:amd64:jdk-latest"     : tier2,
+            "linux:amd64:jdk-latest"     : tier2 + batches(2),
             "linux:aarch64:jdk-latest"   : tier3,
             "darwin:aarch64:jdk-latest"  : tier3,
         }),
diff --git a/graalpython/com.oracle.graal.python.cext/src/graalpy_stacktrace.c b/graalpython/com.oracle.graal.python.cext/src/graalpy_stacktrace.c
index 817a0cc2d3..99e92d0850 100644
--- a/graalpython/com.oracle.graal.python.cext/src/graalpy_stacktrace.c
+++ b/graalpython/com.oracle.graal.python.cext/src/graalpy_stacktrace.c
@@ -55,7 +55,6 @@
 
 #define GRAALPY_NATIVE_STACK_MAX_NAME 1024
 #define GRAALPY_NATIVE_STACK_LINE_BUFFER 2048
-
 typedef void (*GraalPyStacktraceWriter)(void *ctx, const char *line);
 
 static void
@@ -194,7 +193,7 @@ GraalPyPrivate_CaptureStacktrace(void **frames, size_t max_depth, size_t skip)
 #if defined(MS_WINDOWS)
     return (size_t) CaptureStackBackTrace((ULONG) (skip + 1), (ULONG) max_depth, frames, NULL);
 #elif (defined(__linux__) && defined(__GNU_LIBRARY__)) || defined(__APPLE__)
-    int raw_depth = backtrace(frames, (int) max_depth);
+    int raw_depth = backtrace(frames, (int) (max_depth + skip + 1));
     size_t depth = raw_depth > 0 ? (size_t) raw_depth : 0;
     size_t start = depth > (skip + 1) ? (skip + 1) : depth;
     size_t usable_depth = depth - start;
diff --git a/graalpython/com.oracle.graal.python.cext/src/obmalloc.c b/graalpython/com.oracle.graal.python.cext/src/obmalloc.c
index e03c961bac..a05020235a 100644
--- a/graalpython/com.oracle.graal.python.cext/src/obmalloc.c
+++ b/graalpython/com.oracle.graal.python.cext/src/obmalloc.c
@@ -50,9 +50,11 @@ typedef struct {
 	size_t dummy;
 } mem_head_t;
 
+#define GRAALPY_MEM_SAMPLE_USEFUL_DEPTH (10)
+
 typedef struct {
     void *ptr;
-    void *stack[12];
+    void *stack[GRAALPY_MEM_SAMPLE_USEFUL_DEPTH];
     size_t size;
     size_t depth;
     unsigned long long serial;
@@ -70,7 +72,6 @@ typedef struct {
 #define GRAALPY_MEM_SAMPLE_RING_SIZE (4096)
 #define GRAALPY_MEM_SAMPLE_HISTORY (8)
 #define GRAALPY_MEM_SAMPLE_STACK_SKIP (2)
-#define GRAALPY_MEM_SAMPLE_USEFUL_DEPTH (10)
 #define MAX_COLLECTION_RETRIES (7)
 #define COLLECTION_DELAY_INCREMENT (50)