diff --git a/man/depmod.8.scd b/man/depmod.8.scd
index a64ee97e..1cb6cfc2 100644
--- a/man/depmod.8.scd
+++ b/man/depmod.8.scd
@@ -6,7 +6,7 @@ depmod - Generate modules.dep and map files.
 
 # SYNOPSIS
 
-*depmod* [*-b* _basedir_] [*-m* _moduledir_] [*-o* _outdir_][*-o* _outdir_] [*-e*] [*-E* _Module.symvers_]
+*depmod* [*-b* _basedir_] [*-m* _moduledir_] [*-o* _outdir_] [*-e*] [*-E* _Module.symvers_]
 \ \ \ \ \ \ \ \[*-F* _System.map_] [*-n*] [*-v*] [*-A*] [*-P* _prefix_] [*-w*] [_version_]
 
 *depmod* [*-e*] [*-E* _Module.symvers_] [*-F* _System.map_] [*-n*] [*-v*] [*-P* _prefix_]
diff --git a/shared/hash.c b/shared/hash.c
index 38b7bb30..d0e7f86d 100644
--- a/shared/hash.c
+++ b/shared/hash.c
@@ -41,7 +41,7 @@ struct hash *hash_new(unsigned int n_buckets, void (*free_value)(void *value))
 	hash->n_buckets = n_buckets;
 	hash->free_value = free_value;
 	hash->step = n_buckets / 32;
-	if (hash->step == 0)
+	if (hash->step < 4)
 		hash->step = 4;
 	else if (hash->step > 64)
 		hash->step = 64;
@@ -249,6 +249,9 @@ int hash_del(struct hash *hash, const char *key)
 		.value = NULL,
 	};
 
+	if (bucket->entries == NULL)
+		return -ENOENT;
+
 	entry = bsearch(&se, bucket->entries, bucket->used, sizeof(struct hash_entry),
 			hash_entry_cmp);
 	if (entry == NULL)
@@ -258,7 +261,7 @@ int hash_del(struct hash *hash, const char *key)
 		hash->free_value((void *)entry->value);
 
 	entry_end = bucket->entries + bucket->used;
-	memmove(entry, entry + 1, (entry_end - entry) * sizeof(struct hash_entry));
+	memmove(entry, entry + 1, (entry_end - entry - 1) * sizeof(struct hash_entry));
 
 	bucket->used--;
 	hash->count--;
diff --git a/shared/strbuf.c b/shared/strbuf.c
index dad5da52..0dd7a5b0 100644
--- a/shared/strbuf.c
+++ b/shared/strbuf.c
@@ -100,6 +100,9 @@ size_t strbuf_pushmem(struct strbuf *buf, const char *src, size_t sz)
 	assert(src != NULL);
 	assert(buf != NULL);
 
+	if (sz == 0)
+		return 0;
+
 	if (!strbuf_reserve_extra(buf, sz))
 		return 0;
 
diff --git a/testsuite/test-hash.c b/testsuite/test-hash.c
index cfe5a8e4..35cf06ed 100644
--- a/testsuite/test-hash.c
+++ b/testsuite/test-hash.c
@@ -171,6 +171,37 @@ static int test_hash_iter_after_del(const struct test *t)
 DEFINE_TEST(test_hash_iter_after_del,
 	    .description = "test hash_iter, after deleting element");
 
+static int test_hash_del(const struct test *t)
+{
+	struct hash *h = hash_new(32, NULL);
+	const char *k1 = "k1";
+	const char *v1 = "v1";
+
+	hash_add(h, k1, v1);
+	hash_del(h, k1);
+
+	hash_free(h);
+
+	return 0;
+}
+DEFINE_TEST(test_hash_del, .description = "test add / delete a single element");
+
+static int test_hash_del_nonexistent(const struct test *t)
+{
+	struct hash *h = hash_new(32, NULL);
+	const char *k1 = "k1";
+	int rc;
+
+	rc = hash_del(h, k1);
+	assert_return(rc == -ENOENT, EXIT_FAILURE);
+
+	hash_free(h);
+
+	return 0;
+}
+DEFINE_TEST(test_hash_del_nonexistent,
+	    .description = "test deleting an element that doesn't exist");
+
 static int test_hash_free(const struct test *t)
 {
 	struct hash *h = hash_new(8, countfreecalls);
diff --git a/testsuite/test-strbuf.c b/testsuite/test-strbuf.c
index e77fbdb9..50c75d92 100644
--- a/testsuite/test-strbuf.c
+++ b/testsuite/test-strbuf.c
@@ -191,6 +191,7 @@ static int test_strbuf_pushmem(const struct test *t)
 	size_t size;
 
 	strbuf_init(&buf);
+	strbuf_pushmem(&buf, "", 0);
 	strbuf_reserve_extra(&buf, strlen(TEXT) + 1);
 	size = buf.size;
 	strbuf_pushmem(&buf, TEXT, strlen(TEXT) + 1);