diff --git a/Makefile b/Makefile
index 372284d6a0c..1465f36bd61 100644
--- a/Makefile
+++ b/Makefile
@@ -122,7 +122,7 @@ LDFLAGS += $(LDFLAGS_$(CONFIG))
 
 CFLAGS += -std=c89 -pedantic
 CXXFLAGS += -std=c++11
-CPPFLAGS += -g -fPIC -Wall -Werror -Wno-long-long
+CPPFLAGS += -g -fPIC -Wall -Wextra -Werror -Wno-long-long -Wno-unused-parameter
 LDFLAGS += -g -fPIC
 
 INCLUDES = . include gens
diff --git a/include/grpc/byte_buffer_reader.h b/include/grpc/byte_buffer_reader.h
index 6386db65929..a9cbb7752be 100644
--- a/include/grpc/byte_buffer_reader.h
+++ b/include/grpc/byte_buffer_reader.h
@@ -42,7 +42,7 @@ struct grpc_byte_buffer_reader {
   /* Different current objects correspond to different types of byte buffers */
   union {
     /* Index into a slice buffer's array of slices */
-    int index;
+    unsigned index;
   } current;
 };
 
diff --git a/include/grpc/support/port_platform.h b/include/grpc/support/port_platform.h
index 58444d00c3e..58fce64ff18 100644
--- a/include/grpc/support/port_platform.h
+++ b/include/grpc/support/port_platform.h
@@ -155,7 +155,7 @@ typedef uintmax_t gpr_uintmax;
 typedef uintptr_t gpr_uintptr;
 
 /* INT64_MAX is unavailable on some platforms. */
-#define GPR_INT64_MAX (~(gpr_uint64)0 >> 1)
+#define GPR_INT64_MAX (gpr_int64)(~(gpr_uint64)0 >> 1)
 
 /* maximum alignment needed for any type on this platform, rounded up to a
    power of two */
diff --git a/include/grpc/support/slice_buffer.h b/include/grpc/support/slice_buffer.h
index 0ad735a47a3..80c13e064a9 100644
--- a/include/grpc/support/slice_buffer.h
+++ b/include/grpc/support/slice_buffer.h
@@ -73,7 +73,7 @@ size_t gpr_slice_buffer_add_indexed(gpr_slice_buffer *sb, gpr_slice slice);
 void gpr_slice_buffer_addn(gpr_slice_buffer *sb, gpr_slice *slices, size_t n);
 /* add a very small (less than 8 bytes) amount of data to the end of a slice
    buffer: returns a pointer into which to add the data */
-gpr_uint8 *gpr_slice_buffer_tiny_add(gpr_slice_buffer *sb, int len);
+gpr_uint8 *gpr_slice_buffer_tiny_add(gpr_slice_buffer *sb, unsigned len);
 /* clear a slice buffer, unref all elements */
 void gpr_slice_buffer_reset_and_unref(gpr_slice_buffer *sb);
 
diff --git a/src/core/channel/channel_args.c b/src/core/channel/channel_args.c
index 5f16c7b7e99..f48415e6346 100644
--- a/src/core/channel/channel_args.c
+++ b/src/core/channel/channel_args.c
@@ -105,7 +105,7 @@ void grpc_channel_args_destroy(grpc_channel_args *a) {
 }
 
 int grpc_channel_args_is_census_enabled(const grpc_channel_args *a) {
-  int i;
+  unsigned i;
   if (a == NULL) return 0;
   for (i = 0; i < a->num_args; i++) {
     if (0 == strcmp(a->args[i].key, GRPC_ARG_ENABLE_CENSUS)) {
diff --git a/src/core/channel/channel_stack.c b/src/core/channel/channel_stack.c
index af47df844a9..e28bbd798d7 100644
--- a/src/core/channel/channel_stack.c
+++ b/src/core/channel/channel_stack.c
@@ -125,7 +125,8 @@ void grpc_channel_stack_init(const grpc_channel_filter **filters,
     call_size += ROUND_UP_TO_ALIGNMENT_SIZE(filters[i]->sizeof_call_data);
   }
 
-  GPR_ASSERT(user_data - (char *)stack ==
+  GPR_ASSERT(user_data > (char *)stack);
+  GPR_ASSERT((gpr_uintptr)(user_data - (char *)stack) ==
              grpc_channel_stack_size(filters, filter_count));
 
   stack->call_stack_size = call_size;
diff --git a/src/core/channel/http_client_filter.c b/src/core/channel/http_client_filter.c
index 4735aa939cb..96acb385bf2 100644
--- a/src/core/channel/http_client_filter.c
+++ b/src/core/channel/http_client_filter.c
@@ -134,7 +134,7 @@ static void destroy_call_elem(grpc_call_element *elem) {
 }
 
 static const char *scheme_from_args(const grpc_channel_args *args) {
-  int i;
+  unsigned i;
   if (args != NULL) {
     for (i = 0; i < args->num_args; ++i) {
       if (args->args[i].type == GRPC_ARG_STRING &&
diff --git a/src/core/iomgr/tcp_server.h b/src/core/iomgr/tcp_server.h
index c4d836e9b53..2558a1eb9f9 100644
--- a/src/core/iomgr/tcp_server.h
+++ b/src/core/iomgr/tcp_server.h
@@ -68,7 +68,7 @@ int grpc_tcp_server_add_port(grpc_tcp_server *s, const void *addr,
 
    The file descriptor remains owned by the server, and will be cleaned
    up when grpc_tcp_server_destroy is called. */
-int grpc_tcp_server_get_fd(grpc_tcp_server *s, int index);
+int grpc_tcp_server_get_fd(grpc_tcp_server *s, unsigned index);
 
 void grpc_tcp_server_destroy(grpc_tcp_server *server);
 
diff --git a/src/core/iomgr/tcp_server_posix.c b/src/core/iomgr/tcp_server_posix.c
index 10daf450b7d..d169d232718 100644
--- a/src/core/iomgr/tcp_server_posix.c
+++ b/src/core/iomgr/tcp_server_posix.c
@@ -272,7 +272,7 @@ int grpc_tcp_server_add_port(grpc_tcp_server *s, const void *addr,
                              int addr_len) {
   int allocated_port1 = -1;
   int allocated_port2 = -1;
-  int i;
+  unsigned i;
   int fd;
   grpc_dualstack_mode dsmode;
   struct sockaddr_in6 addr6_v4mapped;
@@ -345,8 +345,8 @@ done:
   return allocated_port1 >= 0 ? allocated_port1 : allocated_port2;
 }
 
-int grpc_tcp_server_get_fd(grpc_tcp_server *s, int index) {
-  return (0 <= index && index < s->nports) ? s->ports[index].fd : -1;
+int grpc_tcp_server_get_fd(grpc_tcp_server *s, unsigned index) {
+  return (index < s->nports) ? s->ports[index].fd : -1;
 }
 
 void grpc_tcp_server_start(grpc_tcp_server *s, grpc_pollset *pollset,
diff --git a/src/core/json/json_writer.c b/src/core/json/json_writer.c
index 63c86ac0085..5605694fde5 100644
--- a/src/core/json/json_writer.c
+++ b/src/core/json/json_writer.c
@@ -66,7 +66,7 @@ static void json_writer_output_indent(
       "                "
       "                ";
 
-  int spaces = writer->depth * writer->indent;
+  unsigned spaces = writer->depth * writer->indent;
 
   if (writer->indent == 0) return;
 
diff --git a/src/core/security/base64.c b/src/core/security/base64.c
index f6c3c52327c..63467944dde 100644
--- a/src/core/security/base64.c
+++ b/src/core/security/base64.c
@@ -113,7 +113,8 @@ char *grpc_base64_encode(const void *vdata, size_t data_size, int url_safe,
     *current++ = GRPC_BASE64_PAD_CHAR;
   }
 
-  GPR_ASSERT((current - result) < result_projected_size);
+  GPR_ASSERT(current >= result);
+  GPR_ASSERT((gpr_uintptr)(current - result) < result_projected_size);
   result[current - result] = '\0';
   return result;
 }
diff --git a/src/core/security/credentials.c b/src/core/security/credentials.c
index 5d06f142158..7b7d8f32116 100644
--- a/src/core/security/credentials.c
+++ b/src/core/security/credentials.c
@@ -173,7 +173,9 @@ static void ssl_server_destroy(grpc_server_credentials *creds) {
   gpr_free(creds);
 }
 
-static int ssl_has_request_metadata(const grpc_credentials *creds) { return 0; }
+static int ssl_has_request_metadata(const grpc_credentials *creds) {
+  return 0;
+}
 
 static int ssl_has_request_metadata_only(const grpc_credentials *creds) {
   return 0;
@@ -903,7 +905,9 @@ static void iam_destroy(grpc_credentials *creds) {
   gpr_free(c);
 }
 
-static int iam_has_request_metadata(const grpc_credentials *creds) { return 1; }
+static int iam_has_request_metadata(const grpc_credentials *creds) {
+  return 1;
+}
 
 static int iam_has_request_metadata_only(const grpc_credentials *creds) {
   return 1;
diff --git a/src/core/security/json_token.c b/src/core/security/json_token.c
index b1548f02a7e..8e48686288f 100644
--- a/src/core/security/json_token.c
+++ b/src/core/security/json_token.c
@@ -127,7 +127,8 @@ grpc_auth_json_key grpc_auth_json_key_create_from_string(
     goto end;
   }
   bio = BIO_new(BIO_s_mem());
-  if (BIO_puts(bio, prop_value) != strlen(prop_value)) {
+  success = BIO_puts(bio, prop_value);
+  if ((success < 0) || ((size_t)success != strlen(prop_value))) {
     gpr_log(GPR_ERROR, "Could not write into openssl BIO.");
     goto end;
   }
@@ -240,7 +241,8 @@ static char *dot_concat_and_free_strings(char *str1, char *str2) {
   *(current++) = '.';
   memcpy(current, str2, str2_len);
   current += str2_len;
-  GPR_ASSERT((current - result) == result_len);
+  GPR_ASSERT(current >= result);
+  GPR_ASSERT((gpr_uintptr)(current - result) == result_len);
   *current = '\0';
   gpr_free(str1);
   gpr_free(str2);
diff --git a/src/core/security/secure_endpoint.c b/src/core/security/secure_endpoint.c
index 9f12cf5d60f..31138d694f1 100644
--- a/src/core/security/secure_endpoint.c
+++ b/src/core/security/secure_endpoint.c
@@ -111,7 +111,7 @@ static void call_read_cb(secure_endpoint *ep, gpr_slice *slices, size_t nslices,
 
 static void on_read(void *user_data, gpr_slice *slices, size_t nslices,
                     grpc_endpoint_cb_status error) {
-  int i = 0;
+  unsigned i;
   gpr_uint8 keep_looping = 0;
   int input_buffer_count = 0;
   tsi_result result = TSI_OK;
@@ -221,7 +221,7 @@ static grpc_endpoint_write_status endpoint_write(grpc_endpoint *secure_ep,
                                                  size_t nslices,
                                                  grpc_endpoint_write_cb cb,
                                                  void *user_data) {
-  int i = 0;
+  unsigned i;
   int output_buffer_count = 0;
   tsi_result result = TSI_OK;
   secure_endpoint *ep = (secure_endpoint *)secure_ep;
diff --git a/src/core/security/server_secure_chttp2.c b/src/core/security/server_secure_chttp2.c
index 9dd43278222..480c8827943 100644
--- a/src/core/security/server_secure_chttp2.c
+++ b/src/core/security/server_secure_chttp2.c
@@ -92,7 +92,7 @@ int grpc_server_add_secure_http2_port(grpc_server *server, const char *addr) {
   grpc_resolved_addresses *resolved = NULL;
   grpc_tcp_server *tcp = NULL;
   size_t i;
-  int count = 0;
+  unsigned count = 0;
   int port_num = -1;
   int port_temp;
 
@@ -127,6 +127,7 @@ int grpc_server_add_secure_http2_port(grpc_server *server, const char *addr) {
   if (count != resolved->naddrs) {
     gpr_log(GPR_ERROR, "Only %d addresses added out of total %d resolved",
             count, resolved->naddrs);
+    /* if it's an error, don't we want to goto error; here ? */
   }
   grpc_resolved_addresses_destroy(resolved);
 
diff --git a/src/core/statistics/census_log.c b/src/core/statistics/census_log.c
index 404e92cc621..aea0a33bad7 100644
--- a/src/core/statistics/census_log.c
+++ b/src/core/statistics/census_log.c
@@ -173,7 +173,7 @@ typedef struct census_log_core_local_block {
 struct census_log {
   int discard_old_records;
   /* Number of cores (aka hardware-contexts) */
-  int num_cores;
+  unsigned num_cores;
   /* number of CENSUS_LOG_2_MAX_RECORD_SIZE blocks in log */
   gpr_int32 num_blocks;
   cl_block* blocks;                       /* Block metadata. */
@@ -183,7 +183,7 @@ struct census_log {
   /* Keeps the state of the reader iterator. A value of 0 indicates that
      iterator has reached the end. census_log_init_reader() resets the
      value to num_core to restart iteration. */
-  gpr_int32 read_iterator_state;
+  gpr_uint32 read_iterator_state;
   /* Points to the block being read. If non-NULL, the block is locked for
      reading (block_being_read_->reader_lock is held). */
   cl_block* block_being_read;
diff --git a/src/core/statistics/census_rpc_stats.c b/src/core/statistics/census_rpc_stats.c
index dd3c07e80b3..785c091debc 100644
--- a/src/core/statistics/census_rpc_stats.c
+++ b/src/core/statistics/census_rpc_stats.c
@@ -184,7 +184,7 @@ static void get_stats(census_ht* store, census_aggregated_rpc_stats* data) {
   gpr_mu_lock(&g_mu);
   if (store != NULL) {
     size_t n;
-    int i, j;
+    unsigned i, j;
     gpr_timespec now = gpr_now();
     census_ht_kv* kv = census_ht_get_all_elements(store, &n);
     if (kv != NULL) {
diff --git a/src/core/statistics/hash_table.c b/src/core/statistics/hash_table.c
index 1aee86d3a45..1f7c242c72e 100644
--- a/src/core/statistics/hash_table.c
+++ b/src/core/statistics/hash_table.c
@@ -292,7 +292,7 @@ static void ht_delete_entry_chain(const census_ht_option* options,
 }
 
 void census_ht_destroy(census_ht* ht) {
-  int i;
+  unsigned i;
   for (i = 0; i < ht->num_buckets; ++i) {
     ht_delete_entry_chain(&ht->options, ht->buckets[i].next);
   }
diff --git a/src/core/statistics/window_stats.c b/src/core/statistics/window_stats.c
index be53d818a08..42ff02071ba 100644
--- a/src/core/statistics/window_stats.c
+++ b/src/core/statistics/window_stats.c
@@ -150,7 +150,7 @@ window_stats* census_window_stats_create(int nintervals,
     is->width = size_ns / granularity;
     /* Check for possible overflow issues, and maximize interval size if the
        user requested something large enough. */
-    if (GPR_INT64_MAX - is->width > size_ns) {
+    if ((GPR_INT64_MAX - is->width) > size_ns) {
       is->top = size_ns + is->width;
     } else {
       is->top = GPR_INT64_MAX;
diff --git a/src/core/support/cpu.h b/src/core/support/cpu.h
index 1c2dde74ee1..f8ec2c65220 100644
--- a/src/core/support/cpu.h
+++ b/src/core/support/cpu.h
@@ -38,12 +38,12 @@
 
 /* Return the number of CPU cores on the current system. Will return 0 if
    if information is not available. */
-int gpr_cpu_num_cores(void);
+unsigned gpr_cpu_num_cores(void);
 
 /* Return the CPU on which the current thread is executing; N.B. This should
    be considered advisory only - it is possible that the thread is switched
    to a different CPU at any time. Returns a value in range
    [0, gpr_cpu_num_cores() - 1] */
-int gpr_cpu_current_cpu(void);
+unsigned gpr_cpu_current_cpu(void);
 
 #endif /* __GRPC_INTERNAL_SUPPORT_CPU_H__ */
diff --git a/src/core/support/cpu_linux.c b/src/core/support/cpu_linux.c
index d8006288066..eab8b7fbd05 100644
--- a/src/core/support/cpu_linux.c
+++ b/src/core/support/cpu_linux.c
@@ -75,8 +75,9 @@
 
 #include <grpc/support/log.h>
 
-int gpr_cpu_num_cores(void) {
+unsigned gpr_cpu_num_cores(void) {
   static int ncpus = 0;
+  /* FIXME: !threadsafe */
   if (ncpus == 0) {
     ncpus = sysconf(_SC_NPROCESSORS_ONLN);
     if (ncpus < 1) {
@@ -87,7 +88,7 @@ int gpr_cpu_num_cores(void) {
   return ncpus;
 }
 
-int gpr_cpu_current_cpu(void) {
+unsigned gpr_cpu_current_cpu(void) {
   int cpu = sched_getcpu();
   if (cpu < 0) {
     gpr_log(GPR_ERROR, "Error determining current CPU: %s\n", strerror(errno));
diff --git a/src/core/support/cpu_posix.c b/src/core/support/cpu_posix.c
index 2ea80807fc2..68e8cb9b12f 100644
--- a/src/core/support/cpu_posix.c
+++ b/src/core/support/cpu_posix.c
@@ -45,7 +45,7 @@
 
 static __thread char magic_thread_local;
 
-int gpr_cpu_num_cores(void) {
+unsigned gpr_cpu_num_cores(void) {
   static int ncpus = 0;
   if (ncpus == 0) {
     ncpus = sysconf(_SC_NPROCESSORS_ONLN);
@@ -63,7 +63,7 @@ static size_t shard_ptr(const void *info) {
   return ((x >> 4) ^ (x >> 9) ^ (x >> 14)) % gpr_cpu_num_cores();
 }
 
-int gpr_cpu_current_cpu(void) {
+unsigned gpr_cpu_current_cpu(void) {
   /* NOTE: there's no way I know to return the actual cpu index portably...
      most code that's using this is using it to shard across work queues though,
      so here we use thread identity instead to achieve a similar though not
diff --git a/src/core/support/histogram.c b/src/core/support/histogram.c
index 425421c5b97..cd360c5a225 100644
--- a/src/core/support/histogram.c
+++ b/src/core/support/histogram.c
@@ -77,7 +77,6 @@ static size_t bucket_for_unchecked(gpr_histogram *h, double x) {
 /* bounds checked version of the above */
 static size_t bucket_for(gpr_histogram *h, double x) {
   size_t bucket = bucket_for_unchecked(h, GPR_CLAMP(x, 0, h->max_possible));
-  GPR_ASSERT(bucket >= 0);
   GPR_ASSERT(bucket < h->num_buckets);
   return bucket;
 }
diff --git a/src/core/support/slice_buffer.c b/src/core/support/slice_buffer.c
index 2ade049c89c..22bda966597 100644
--- a/src/core/support/slice_buffer.c
+++ b/src/core/support/slice_buffer.c
@@ -55,7 +55,7 @@ void gpr_slice_buffer_destroy(gpr_slice_buffer *sb) {
   gpr_free(sb->slices);
 }
 
-gpr_uint8 *gpr_slice_buffer_tiny_add(gpr_slice_buffer *sb, int n) {
+gpr_uint8 *gpr_slice_buffer_tiny_add(gpr_slice_buffer *sb, unsigned n) {
   gpr_slice *back;
   gpr_uint8 *out;
 
@@ -64,7 +64,7 @@ gpr_uint8 *gpr_slice_buffer_tiny_add(gpr_slice_buffer *sb, int n) {
   if (sb->count == 0) goto add_new;
   back = &sb->slices[sb->count - 1];
   if (back->refcount) goto add_new;
-  if (back->data.inlined.length + n > sizeof(back->data.inlined.bytes))
+  if ((back->data.inlined.length + n) > sizeof(back->data.inlined.bytes))
     goto add_new;
   out = back->data.inlined.bytes + back->data.inlined.length;
   back->data.inlined.length += n;
diff --git a/src/core/support/string_posix.c b/src/core/support/string_posix.c
index 7b7e82e1e43..57832810ad3 100644
--- a/src/core/support/string_posix.c
+++ b/src/core/support/string_posix.c
@@ -57,7 +57,7 @@ int gpr_asprintf(char **strp, const char *format, ...) {
   va_start(args, format);
   ret = vsnprintf(buf, sizeof(buf), format, args);
   va_end(args);
-  if (!(0 <= ret && ret < ~(size_t)0)) {
+  if (!(0 <= ret)) {
     *strp = NULL;
     return -1;
   }
@@ -79,7 +79,7 @@ int gpr_asprintf(char **strp, const char *format, ...) {
   va_start(args, format);
   ret = vsnprintf(*strp, strp_buflen, format, args);
   va_end(args);
-  if (ret == strp_buflen - 1) {
+  if ((size_t)ret == strp_buflen - 1) {
     return ret;
   }
 
diff --git a/src/core/support/thd_posix.c b/src/core/support/thd_posix.c
index 1189e0c3f95..bac1d9c2203 100644
--- a/src/core/support/thd_posix.c
+++ b/src/core/support/thd_posix.c
@@ -43,6 +43,7 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/thd.h>
+#include <grpc/support/useful.h>
 
 struct thd_arg {
   void (*body)(void *arg); /* body of a thread */
diff --git a/src/core/surface/server_chttp2.c b/src/core/surface/server_chttp2.c
index 47fca827f38..5ba7d47efd9 100644
--- a/src/core/surface/server_chttp2.c
+++ b/src/core/surface/server_chttp2.c
@@ -75,7 +75,7 @@ int grpc_server_add_http2_port(grpc_server *server, const char *addr) {
   grpc_resolved_addresses *resolved = NULL;
   grpc_tcp_server *tcp = NULL;
   size_t i;
-  int count = 0;
+  unsigned count = 0;
   int port_num = -1;
   int port_temp;
 
diff --git a/src/core/tsi/fake_transport_security.c b/src/core/tsi/fake_transport_security.c
index 0b245e4043d..a96c7df4a34 100644
--- a/src/core/tsi/fake_transport_security.c
+++ b/src/core/tsi/fake_transport_security.c
@@ -38,6 +38,7 @@
 
 #include <grpc/support/log.h>
 #include <grpc/support/port_platform.h>
+#include <grpc/support/useful.h>
 #include "src/core/tsi/transport_security.h"
 
 /* --- Constants. ---*/
@@ -412,7 +413,7 @@ static tsi_result fake_handshaker_process_bytes_from_peer(
     tsi_handshaker* self, const unsigned char* bytes, size_t* bytes_size) {
   tsi_result result = TSI_OK;
   tsi_fake_handshaker* impl = (tsi_fake_handshaker*)self;
-  int expected_msg = impl->next_message_to_send - 1;
+  tsi_fake_handshake_message expected_msg = impl->next_message_to_send - 1;
   tsi_fake_handshake_message received_msg;
 
   if (!impl->needs_incoming_message || impl->result == TSI_OK) {
diff --git a/src/core/tsi/ssl_transport_security.c b/src/core/tsi/ssl_transport_security.c
index 8801cc43df5..0f8cbccb625 100644
--- a/src/core/tsi/ssl_transport_security.c
+++ b/src/core/tsi/ssl_transport_security.c
@@ -37,6 +37,7 @@
 
 #include <grpc/support/log.h>
 #include <grpc/support/sync.h>
+#include <grpc/support/useful.h>
 #include "src/core/tsi/transport_security.h"
 
 #include <openssl/bio.h>
@@ -565,7 +566,8 @@ static tsi_result build_alpn_protocol_name_list(
     current += alpn_protocols_lengths[i];
   }
   /* Safety check. */
-  if ((current - *protocol_name_list) != *protocol_name_list_length) {
+  if ((current < *protocol_name_list) ||
+      ((gpr_uintptr)(current - *protocol_name_list) != *protocol_name_list_length)) {
     return TSI_INTERNAL_ERROR;
   }
   return TSI_OK;
@@ -1063,7 +1065,8 @@ static int server_handshaker_factory_alpn_callback(
   while ((client_current - in) < inlen) {
     unsigned char client_current_len = *(client_current++);
     const unsigned char* server_current = factory->alpn_protocol_list;
-    while ((server_current - factory->alpn_protocol_list) <
+    while ((server_current >= factory->alpn_protocol_list) &&
+           (gpr_uintptr)(server_current - factory->alpn_protocol_list) <
            factory->alpn_protocol_list_length) {
       unsigned char server_current_len = *(server_current++);
       if ((client_current_len == server_current_len) &&
diff --git a/templates/Makefile.template b/templates/Makefile.template
index a3de50c0811..142d188d0c6 100644
--- a/templates/Makefile.template
+++ b/templates/Makefile.template
@@ -139,7 +139,7 @@ LDFLAGS += $(LDFLAGS_$(CONFIG))
 
 CFLAGS += -std=c89 -pedantic
 CXXFLAGS += -std=c++11
-CPPFLAGS += -g -fPIC -Wall -Werror -Wno-long-long
+CPPFLAGS += -g -fPIC -Wall -Wextra -Werror -Wno-long-long -Wno-unused-parameter
 LDFLAGS += -g -fPIC
 
 INCLUDES = . include gens
diff --git a/test/core/channel/channel_stack_test.c b/test/core/channel/channel_stack_test.c
index a400fb15bd9..d53098b5e42 100644
--- a/test/core/channel/channel_stack_test.c
+++ b/test/core/channel/channel_stack_test.c
@@ -80,7 +80,7 @@ static void test_create_channel_stack(void) {
   const grpc_channel_filter
       filter = {call_func,         channel_func,         sizeof(int),
                 call_init_func,    call_destroy_func,    sizeof(int),
-                channel_init_func, channel_destroy_func, };
+                channel_init_func, channel_destroy_func, "some_test_filter" };
   const grpc_channel_filter *filters = &filter;
   grpc_channel_stack *channel_stack;
   grpc_call_stack *call_stack;
diff --git a/test/core/channel/metadata_buffer_test.c b/test/core/channel/metadata_buffer_test.c
index 9d7e1591f86..60813089868 100644
--- a/test/core/channel/metadata_buffer_test.c
+++ b/test/core/channel/metadata_buffer_test.c
@@ -112,12 +112,12 @@ static void destroy_channel_elem(grpc_channel_element *elem) {}
 static const grpc_channel_filter top_filter = {
     fail_call_op,      fail_channel_op,     sizeof(size_t),
     init_call_elem,    destroy_call_elem,   sizeof(channel_data),
-    init_channel_elem, destroy_channel_elem};
+    init_channel_elem, destroy_channel_elem, "top_filter" };
 
 static const grpc_channel_filter bottom_filter = {
     expect_call_op,    fail_channel_op,     sizeof(size_t),
     init_call_elem,    destroy_call_elem,   sizeof(channel_data),
-    init_channel_elem, destroy_channel_elem};
+    init_channel_elem, destroy_channel_elem, "bottom_filter" };
 
 static const grpc_channel_filter *filters[2] = {&top_filter, &bottom_filter};
 
diff --git a/test/core/compression/message_compress_test.c b/test/core/compression/message_compress_test.c
index d1e593564f4..5f55fa68d32 100644
--- a/test/core/compression/message_compress_test.c
+++ b/test/core/compression/message_compress_test.c
@@ -166,7 +166,7 @@ static void test_bad_data(void) {
 }
 
 int main(int argc, char **argv) {
-  int i, j, k, m;
+  unsigned i, j, k, m;
   grpc_slice_split_mode uncompressed_split_modes[] = {
       GRPC_SLICE_SPLIT_IDENTITY, GRPC_SLICE_SPLIT_ONE_BYTE};
   grpc_slice_split_mode compressed_split_modes[] = {GRPC_SLICE_SPLIT_MERGE_ALL,
diff --git a/test/core/echo/client.c b/test/core/echo/client.c
index 2f35b03228a..bb478c4b4b8 100644
--- a/test/core/echo/client.c
+++ b/test/core/echo/client.c
@@ -66,7 +66,7 @@ int main(int argc, char **argv) {
   grpc_completion_queue *cq = NULL;
   int bytes_written = 0;
   int bytes_read = 0;
-  int i = 0;
+  unsigned i = 0;
   int waiting_finishes;
   gpr_slice read_slice;
 
diff --git a/test/core/echo/server.c b/test/core/echo/server.c
index 6b67334248a..2764a9ef0e0 100644
--- a/test/core/echo/server.c
+++ b/test/core/echo/server.c
@@ -70,7 +70,7 @@ static void request_call(void) {
 static void assert_read_ok(call_state *s, grpc_byte_buffer *b) {
   grpc_byte_buffer_reader *bb_reader = NULL;
   gpr_slice read_slice;
-  int i;
+  unsigned i;
 
   bb_reader = grpc_byte_buffer_reader_create(b);
   while (grpc_byte_buffer_reader_next(bb_reader, &read_slice)) {
diff --git a/test/core/end2end/tests/cancel_after_accept.c b/test/core/end2end/tests/cancel_after_accept.c
index 33aed98c38c..05a2dc8bbb8 100644
--- a/test/core/end2end/tests/cancel_after_accept.c
+++ b/test/core/end2end/tests/cancel_after_accept.c
@@ -149,7 +149,7 @@ static void test_cancel_after_accept(grpc_end2end_test_config config,
 }
 
 void grpc_end2end_tests(grpc_end2end_test_config config) {
-  int i;
+  unsigned i;
 
   for (i = 0; i < GPR_ARRAY_SIZE(cancellation_modes); i++) {
     test_cancel_after_accept(config, cancellation_modes[i]);
diff --git a/test/core/end2end/tests/cancel_after_accept_and_writes_closed.c b/test/core/end2end/tests/cancel_after_accept_and_writes_closed.c
index f348488b182..db245a37e1b 100644
--- a/test/core/end2end/tests/cancel_after_accept_and_writes_closed.c
+++ b/test/core/end2end/tests/cancel_after_accept_and_writes_closed.c
@@ -157,7 +157,7 @@ static void test_cancel_after_accept_and_writes_closed(
 }
 
 void grpc_end2end_tests(grpc_end2end_test_config config) {
-  int i;
+  unsigned i;
 
   for (i = 0; i < GPR_ARRAY_SIZE(cancellation_modes); i++) {
     test_cancel_after_accept_and_writes_closed(config, cancellation_modes[i]);
diff --git a/test/core/end2end/tests/cancel_after_invoke.c b/test/core/end2end/tests/cancel_after_invoke.c
index 3bb86723e6e..5dfb3f756ab 100644
--- a/test/core/end2end/tests/cancel_after_invoke.c
+++ b/test/core/end2end/tests/cancel_after_invoke.c
@@ -132,7 +132,7 @@ static void test_cancel_after_invoke(grpc_end2end_test_config config,
 }
 
 void grpc_end2end_tests(grpc_end2end_test_config config) {
-  int i;
+  unsigned i;
 
   for (i = 0; i < GPR_ARRAY_SIZE(cancellation_modes); i++) {
     test_cancel_after_invoke(config, cancellation_modes[i]);
diff --git a/test/core/end2end/tests/cancel_in_a_vacuum.c b/test/core/end2end/tests/cancel_in_a_vacuum.c
index e4f9deecd1b..5257ece297e 100644
--- a/test/core/end2end/tests/cancel_in_a_vacuum.c
+++ b/test/core/end2end/tests/cancel_in_a_vacuum.c
@@ -122,7 +122,7 @@ static void test_cancel_in_a_vacuum(grpc_end2end_test_config config,
 }
 
 void grpc_end2end_tests(grpc_end2end_test_config config) {
-  int i;
+  unsigned i;
 
   for (i = 0; i < GPR_ARRAY_SIZE(cancellation_modes); i++) {
     test_cancel_in_a_vacuum(config, cancellation_modes[i]);
diff --git a/test/core/fling/client.c b/test/core/fling/client.c
index 7947ffecc5c..8f910985911 100644
--- a/test/core/fling/client.c
+++ b/test/core/fling/client.c
@@ -103,7 +103,7 @@ static const scenario scenarios[] = {
 int main(int argc, char **argv) {
   gpr_slice slice = gpr_slice_from_copied_string("x");
   double start, stop;
-  int i;
+  unsigned i;
 
   char *fake_argv[1];
 
diff --git a/test/core/iomgr/resolve_address_test.c b/test/core/iomgr/resolve_address_test.c
index 4cc101b6b0f..1f97724e607 100644
--- a/test/core/iomgr/resolve_address_test.c
+++ b/test/core/iomgr/resolve_address_test.c
@@ -85,7 +85,7 @@ static void test_ipv6_with_port(void) {
 static void test_ipv6_without_port(void) {
   const char* const kCases[] = {"2001:db8::1", "2001:db8::1.2.3.4",
                                 "[2001:db8::1]", };
-  int i;
+  unsigned i;
   for (i = 0; i < sizeof(kCases) / sizeof(*kCases); i++) {
     gpr_event ev;
     gpr_event_init(&ev);
@@ -96,7 +96,7 @@ static void test_ipv6_without_port(void) {
 
 static void test_invalid_ip_addresses(void) {
   const char* const kCases[] = {"293.283.1238.3:1", "[2001:db8::11111]:1", };
-  int i;
+  unsigned i;
   for (i = 0; i < sizeof(kCases) / sizeof(*kCases); i++) {
     gpr_event ev;
     gpr_event_init(&ev);
@@ -108,7 +108,7 @@ static void test_invalid_ip_addresses(void) {
 static void test_unparseable_hostports(void) {
   const char* const kCases[] = {"[",         "[::1",        "[::1]bad",
                                 "[1.2.3.4]", "[localhost]", "[localhost]:1", };
-  int i;
+  unsigned i;
   for (i = 0; i < sizeof(kCases) / sizeof(*kCases); i++) {
     gpr_event ev;
     gpr_event_init(&ev);
diff --git a/test/core/iomgr/sockaddr_utils_test.c b/test/core/iomgr/sockaddr_utils_test.c
index 3e653da4c97..6cbdc4e21c1 100644
--- a/test/core/iomgr/sockaddr_utils_test.c
+++ b/test/core/iomgr/sockaddr_utils_test.c
@@ -182,7 +182,8 @@ static void expect_sockaddr_str(const char *expected, void *addr,
   gpr_log(GPR_INFO, "  expect_sockaddr_str(%s)", expected);
   result = grpc_sockaddr_to_string(&str, (struct sockaddr *)addr, normalize);
   GPR_ASSERT(str != NULL);
-  GPR_ASSERT(result == strlen(str));
+  GPR_ASSERT(result >= 0);
+  GPR_ASSERT((size_t)result == strlen(str));
   GPR_ASSERT(strcmp(expected, str) == 0);
   gpr_free(str);
 }
@@ -194,7 +195,7 @@ static void test_sockaddr_to_string(void) {
 
   gpr_log(GPR_INFO, "%s", __FUNCTION__);
 
-  errno = 0xDEADBEEF;
+  errno = 0x7EADBEEF;
 
   input4 = make_addr4(kIPv4, sizeof(kIPv4));
   expect_sockaddr_str("192.0.2.1:12345", &input4, 0);
@@ -217,7 +218,7 @@ static void test_sockaddr_to_string(void) {
   expect_sockaddr_str("(sockaddr family=123)", &dummy, 0);
   expect_sockaddr_str("(sockaddr family=123)", &dummy, 1);
 
-  GPR_ASSERT(errno == 0xDEADBEEF);
+  GPR_ASSERT(errno == 0x7EADBEEF);
 }
 
 int main(int argc, char **argv) {
diff --git a/test/core/iomgr/tcp_posix_test.c b/test/core/iomgr/tcp_posix_test.c
index 24634b47007..f52ae229812 100644
--- a/test/core/iomgr/tcp_posix_test.c
+++ b/test/core/iomgr/tcp_posix_test.c
@@ -94,7 +94,7 @@ static size_t fill_socket_partial(int fd, size_t bytes) {
   ssize_t write_bytes;
   size_t total_bytes = 0;
   unsigned char *buf = malloc(bytes);
-  int i;
+  unsigned i;
   for (i = 0; i < bytes; ++i) {
     buf[i] = i % 256;
   }
@@ -115,15 +115,14 @@ struct read_socket_state {
   grpc_endpoint *ep;
   gpr_mu mu;
   gpr_cv cv;
-  size_t read_bytes;
+  ssize_t read_bytes;
   ssize_t target_read_bytes;
 };
 
 static ssize_t count_and_unref_slices(gpr_slice *slices, size_t nslices,
                                       int *current_data) {
   ssize_t num_bytes = 0;
-  int i;
-  int j;
+  unsigned i, j;
   unsigned char *buf;
   for (i = 0; i < nslices; ++i) {
     buf = GPR_SLICE_START_PTR(slices[i]);
@@ -254,8 +253,7 @@ static gpr_slice *allocate_blocks(ssize_t num_bytes, ssize_t slice_size,
   ssize_t nslices = num_bytes / slice_size + (num_bytes % slice_size ? 1 : 0);
   gpr_slice *slices = gpr_malloc(sizeof(gpr_slice) * nslices);
   ssize_t num_bytes_left = num_bytes;
-  int i;
-  int j;
+  unsigned i, j;
   unsigned char *buf;
   *num_blocks = nslices;
 
diff --git a/test/core/json/json_rewrite.c b/test/core/json/json_rewrite.c
index edece98d570..a761a670f0e 100644
--- a/test/core/json/json_rewrite.c
+++ b/test/core/json/json_rewrite.c
@@ -131,7 +131,7 @@ static void json_reader_string_add_utf32(void* userdata, gpr_uint32 c) {
 }
 
 static gpr_uint32 json_reader_read_char(void* userdata) {
-  gpr_uint32 r;
+  int r;
   json_reader_userdata* state = userdata;
 
   r = fgetc(state->in);
diff --git a/test/core/json/json_rewrite_test.c b/test/core/json/json_rewrite_test.c
index e47a418761c..4ce406c9909 100644
--- a/test/core/json/json_rewrite_test.c
+++ b/test/core/json/json_rewrite_test.c
@@ -138,7 +138,7 @@ static void json_reader_string_add_utf32(void* userdata, gpr_uint32 c) {
 }
 
 static gpr_uint32 json_reader_read_char(void* userdata) {
-  gpr_uint32 r;
+  int r;
   json_reader_userdata* state = userdata;
 
   if (!state->did_eagain) {
@@ -298,7 +298,7 @@ static test_file test_files[] = {
 };
 
 void test_rewrites() {
-  int i;
+  unsigned i;
 
   for (i = 0; i < GPR_ARRAY_SIZE(test_files); i++) {
     test_file* test = test_files + i;
diff --git a/test/core/json/json_test.c b/test/core/json/json_test.c
index c234eb9ede1..11659a57161 100644
--- a/test/core/json/json_test.c
+++ b/test/core/json/json_test.c
@@ -124,7 +124,7 @@ static testing_pair testing_pairs[] = {
 };
 
 static void test_pairs() {
-  int i;
+  unsigned i;
 
   for (i = 0; i < GPR_ARRAY_SIZE(testing_pairs); i++) {
     testing_pair* pair = testing_pairs + i;
diff --git a/test/core/security/secure_endpoint_test.c b/test/core/security/secure_endpoint_test.c
index 5d875025ec3..456515bfd50 100644
--- a/test/core/security/secure_endpoint_test.c
+++ b/test/core/security/secure_endpoint_test.c
@@ -59,7 +59,7 @@ static grpc_endpoint_test_fixture secure_endpoint_create_fixture_tcp_socketpair(
     f.client_ep =
         grpc_secure_endpoint_create(fake_read_protector, tcp.client, NULL, 0);
   } else {
-    int i;
+    unsigned i;
     tsi_result result;
     size_t still_pending_size;
     size_t total_buffer_size = 8192;
@@ -81,9 +81,8 @@ static grpc_endpoint_test_fixture secure_endpoint_create_fixture_tcp_socketpair(
         message_bytes += processed_message_size;
         message_size -= processed_message_size;
         cur += protected_buffer_size_to_send;
+        GPR_ASSERT(buffer_size >= protected_buffer_size_to_send);
         buffer_size -= protected_buffer_size_to_send;
-
-        GPR_ASSERT(buffer_size >= 0);
       }
       gpr_slice_unref(plain);
     }
@@ -94,8 +93,8 @@ static grpc_endpoint_test_fixture secure_endpoint_create_fixture_tcp_socketpair(
                                                  &still_pending_size);
       GPR_ASSERT(result == TSI_OK);
       cur += protected_buffer_size_to_send;
+      GPR_ASSERT(buffer_size >= protected_buffer_size_to_send);
       buffer_size -= protected_buffer_size_to_send;
-      GPR_ASSERT(buffer_size >= 0);
     } while (still_pending_size > 0);
     encrypted_leftover = gpr_slice_from_copied_buffer(
         (const char *)encrypted_buffer, total_buffer_size - buffer_size);
diff --git a/test/core/statistics/census_log_tests.c b/test/core/statistics/census_log_tests.c
index ca2d1dedb03..c7b2b2e46dc 100644
--- a/test/core/statistics/census_log_tests.c
+++ b/test/core/statistics/census_log_tests.c
@@ -415,8 +415,8 @@ void test_read_pending_record(void) {
 /* Tries reading beyond pending write. */
 void test_read_beyond_pending_record(void) {
   /* Start a write. */
-  gpr_int32 incomplete_record_size = 10;
-  gpr_int32 complete_record_size = 20;
+  gpr_uint32 incomplete_record_size = 10;
+  gpr_uint32 complete_record_size = 20;
   size_t bytes_available;
   void* complete_record;
   const void* record_read;
@@ -457,7 +457,7 @@ void test_detached_while_reading(void) {
   size_t bytes_available;
   const void* record_read;
   void* record_written;
-  gpr_int32 block_read = 0;
+  gpr_uint32 block_read = 0;
   printf("Starting test: detached while reading\n");
   setup_test(0);
   /* Start a write. */
diff --git a/test/core/statistics/hash_table_test.c b/test/core/statistics/hash_table_test.c
index f8df2574a42..e8e4d8b6f1d 100644
--- a/test/core/statistics/hash_table_test.c
+++ b/test/core/statistics/hash_table_test.c
@@ -190,7 +190,7 @@ static void test_insertion_and_deletion_with_high_collision_rate(void) {
   census_ht* ht = census_ht_create(&opt);
   char key_str[1000][GPR_LTOA_MIN_BUFSIZE];
   gpr_uint64 val = 0;
-  int i = 0;
+  unsigned i = 0;
   for (i = 0; i < 1000; i++) {
     census_ht_key key;
     key.ptr = key_str[i];
diff --git a/test/core/support/host_port_test.c b/test/core/support/host_port_test.c
index 5b06b7076ee..6d14fab8636 100644
--- a/test/core/support/host_port_test.c
+++ b/test/core/support/host_port_test.c
@@ -43,7 +43,8 @@ static void join_host_port_expect(const char *host, int port,
   char *buf;
   int len;
   len = gpr_join_host_port(&buf, host, port);
-  GPR_ASSERT(strlen(expected) == len);
+  GPR_ASSERT(len >= 0);
+  GPR_ASSERT(strlen(expected) == (size_t)len);
   GPR_ASSERT(strcmp(expected, buf) == 0);
   gpr_free(buf);
 }
diff --git a/test/core/support/slice_test.c b/test/core/support/slice_test.c
index 2a7056feb2d..469d7dedc3b 100644
--- a/test/core/support/slice_test.c
+++ b/test/core/support/slice_test.c
@@ -103,10 +103,10 @@ static void test_slice_new_with_len_returns_something_sensible(void) {
   GPR_ASSERT(do_nothing_with_len_1_calls == 1);
 }
 
-static void test_slice_sub_works(int length) {
+static void test_slice_sub_works(unsigned length) {
   gpr_slice slice;
   gpr_slice sub;
-  int i, j, k;
+  unsigned i, j, k;
 
   LOG_TEST_NAME();
   gpr_log(GPR_INFO, "length=%d", length);
@@ -212,7 +212,7 @@ static void test_slice_from_copied_string_works(void) {
 }
 
 int main(int argc, char **argv) {
-  int length;
+  unsigned length;
   grpc_test_init(argc, argv);
   test_slice_malloc_returns_something_sensible();
   test_slice_new_returns_something_sensible();
diff --git a/test/core/surface/completion_queue_test.c b/test/core/surface/completion_queue_test.c
index 71f9cc22916..dc459d62a8f 100644
--- a/test/core/surface/completion_queue_test.c
+++ b/test/core/surface/completion_queue_test.c
@@ -214,7 +214,7 @@ static void test_pluck(void) {
   grpc_event *ev;
   grpc_completion_queue *cc;
   void *tags[128];
-  int i, j;
+  unsigned i, j;
   int on_finish_called = 0;
 
   LOG_TEST();
diff --git a/test/core/transport/chttp2/timeout_encoding_test.c b/test/core/transport/chttp2/timeout_encoding_test.c
index 0ad90dbcef8..56a1e6ee638 100644
--- a/test/core/transport/chttp2/timeout_encoding_test.c
+++ b/test/core/transport/chttp2/timeout_encoding_test.c
@@ -94,7 +94,7 @@ void decode_suite(char ext, gpr_timespec (*answer)(long x)) {
   long test_vals[] = {1,       12,       123,       1234,     12345,   123456,
                       1234567, 12345678, 123456789, 98765432, 9876543, 987654,
                       98765,   9876,     987,       98,       9};
-  int i;
+  unsigned i;
   char *input;
   for (i = 0; i < GPR_ARRAY_SIZE(test_vals); i++) {
     gpr_asprintf(&input, "%ld%c", test_vals[i], ext);
diff --git a/test/core/transport/stream_op_test.c b/test/core/transport/stream_op_test.c
index 0d1122c0ada..e6649ec97c2 100644
--- a/test/core/transport/stream_op_test.c
+++ b/test/core/transport/stream_op_test.c
@@ -61,7 +61,7 @@ int main(int argc, char **argv) {
   gpr_slice test_slice_3 = gpr_slice_malloc(3);
   gpr_slice test_slice_4 = gpr_slice_malloc(4);
   char x;
-  int i;
+  unsigned i;
 
   grpc_stream_op_buffer buf;
   grpc_stream_op_buffer buf2;
diff --git a/test/core/transport/transport_end2end_tests.c b/test/core/transport/transport_end2end_tests.c
index 25276c0fca4..2cd033bf3ac 100644
--- a/test/core/transport/transport_end2end_tests.c
+++ b/test/core/transport/transport_end2end_tests.c
@@ -913,7 +913,7 @@ static const size_t interesting_message_lengths[] = {1,      100,     10000,
                                                      100000, 1000000, };
 
 void grpc_transport_end2end_tests(grpc_transport_test_config *config) {
-  int i;
+  unsigned i;
 
   g_metadata_context = grpc_mdctx_create();