Detect memory leaks when memory type is being destroyed.

This is very helpful for detecting kernel modules memory leaks on unload.

Discussed and reviewed by:	rwatson

1 files changed, 21 insertions, 0 deletions

diff --git a/sys/kern/kern_malloc.c b/sys/kern/kern_malloc.c
index 6073e9c..4b707aa 100644
--- a/sys/kern/kern_malloc.c
+++ b/sys/kern/kern_malloc.c
@@ -608,7 +608,10 @@ void
 malloc_uninit(void *data)
 {
 	struct malloc_type_internal *mtip;
+	struct malloc_type_stats *mtsp;
 	struct malloc_type *mtp, *temp;
+	long temp_allocs, temp_bytes;
+	int i;
 
 	mtp = data;
 	KASSERT(mtp->ks_handle != NULL, ("malloc_deregister: cookie NULL"));
@@ -625,6 +628,24 @@ malloc_uninit(void *data)
 		kmemstatistics = mtp->ks_next;
 	kmemcount--;
 	mtx_unlock(&malloc_mtx);
+
+	/*
+	 * Look for memory leaks.
+	 */
+	temp_allocs = temp_bytes = 0;
+	for (i = 0; i < MAXCPU; i++) {
+		mtsp = &mtip->mti_stats[i];
+		temp_allocs += mtsp->mts_numallocs;
+		temp_allocs -= mtsp->mts_numfrees;
+		temp_bytes += mtsp->mts_memalloced;
+		temp_bytes -= mtsp->mts_memfreed;
+	}
+	if (temp_allocs > 0 || temp_bytes > 0) {
+		printf("Warning: memory type %s leaked memory on destroy "
+		    "(%ld allocations, %ld bytes leaked).\n", mtp->ks_shortdesc,
+		    temp_allocs, temp_bytes);
+	}
+
 	uma_zfree(mt_zone, mtip);
 }