diff --git a/qa/workunits/cephtool/test.sh b/qa/workunits/cephtool/test.sh
index 7fe688de1de..8ddfa30d199 100755
--- a/qa/workunits/cephtool/test.sh
+++ b/qa/workunits/cephtool/test.sh
@@ -196,11 +196,14 @@ function test_mon_injectargs()
   check_response "osd_enable_op_tracker = 'true'"
   ceph tell osd.0 injectargs -- '--osd_enable_op_tracker --osd_op_history_duration 600' >& $TMPFILE || return 1
   check_response "osd_enable_op_tracker = 'true' osd_op_history_duration = '600'"
-  ceph tell osd.0 injectargs -- '--osd_op_history_duration' >& $TMPFILE || return 1
-  check_response "Option --osd_op_history_duration requires an argument"
+  expect_failure $TMPDIR "Option --osd_op_history_duration requires an argument" \
+                 ceph tell osd.0 injectargs -- '--osd_op_history_duration'
 
   ceph tell osd.0 injectargs -- '--mon-lease 6' >& $TMPFILE || return 1
   check_response "mon_lease = '6' (unchangeable)"
+
+  # osd-scrub-auto-repair-num-errors is an OPT_U32, so -1 is not a valid setting
+  expect_false ceph tell osd.0 injectargs --osd-scrub-auto-repair-num-errors -1
 }
 
 function test_mon_injectargs_SI()
@@ -228,6 +231,7 @@ function test_mon_injectargs_SI()
   ceph tell mon.a injectargs '--mon_pg_warn_min_objects 1G'
   expect_config_value "mon.a" "mon_pg_warn_min_objects" 1073741824
   expect_false ceph tell mon.a injectargs '--mon_pg_warn_min_objects 10F'
+  expect_false ceph tell mon.a injectargs '--mon_globalid_prealloc -1'
   $SUDO ceph daemon mon.a config set mon_pg_warn_min_objects $initial_value
 }
 
@@ -734,6 +738,7 @@ function test_mds_tell()
   for mds_gid in $old_mds_gids ; do
       ceph tell mds.$mds_gid injectargs "--debug-mds 20"
   done
+  expect_false ceph tell mds.a injectargs mds_max_file_recover -1
 
   # Test respawn by rank
   ceph tell mds.0 respawn
@@ -1673,11 +1678,12 @@ function test_osd_bench()
   # max block size: 2097152   # 2MB
   # duration: 10              # 10 seconds
 
-  ceph tell osd.0 injectargs "\
+  local args="\
     --osd-bench-duration 10 \
     --osd-bench-max-block-size 2097152 \
     --osd-bench-large-size-max-throughput 10485760 \
     --osd-bench-small-size-max-iops 10"
+  ceph tell osd.0 injectargs ${args## }
 
   # anything with a bs larger than 2097152  must fail
   expect_false ceph tell osd.0 bench 1 2097153
diff --git a/src/common/config.cc b/src/common/config.cc
index 47c01797dc1..ddbb2d0f32d 100644
--- a/src/common/config.cc
+++ b/src/common/config.cc
@@ -998,7 +998,7 @@ int md_config_t::set_val_raw(const char *val, const config_option *opt)
       return 0;
     case OPT_U32: {
       std::string err;
-      int f = strict_si_cast<int>(val, &err);
+      int f = strict_si_cast<uint32_t>(val, &err);
       if (!err.empty())
 	return -EINVAL;
       *(uint32_t*)opt->conf_ptr(this) = f;
diff --git a/src/common/strtol.cc b/src/common/strtol.cc
index 50598b9288e..bc5ccc74cb1 100644
--- a/src/common/strtol.cc
+++ b/src/common/strtol.cc
@@ -186,10 +186,9 @@ T strict_si_cast(const char *str, std::string *err)
 }
 
 template int strict_si_cast<int>(const char *str, std::string *err);
-
 template long long strict_si_cast<long long>(const char *str, std::string *err);
-
 template uint64_t strict_si_cast<uint64_t>(const char *str, std::string *err);
+template uint32_t strict_si_cast<uint32_t>(const char *str, std::string *err);
 
 uint64_t strict_sistrtoll(const char *str, std::string *err)
 {
diff --git a/src/mds/MDSDaemon.cc b/src/mds/MDSDaemon.cc
index e7d9fe51b13..8b61afa85ee 100644
--- a/src/mds/MDSDaemon.cc
+++ b/src/mds/MDSDaemon.cc
@@ -769,7 +769,7 @@ int MDSDaemon::_handle_command(
     string args = argsvec.front();
     for (vector<string>::iterator a = ++argsvec.begin(); a != argsvec.end(); ++a)
       args += " " + *a;
-    cct->_conf->injectargs(args, &ss);
+    r = cct->_conf->injectargs(args, &ss);
   } else if (prefix == "exit") {
     // We will send response before executing
     ss << "Exiting...";
diff --git a/src/osd/OSD.cc b/src/osd/OSD.cc
index bac252818cf..5481d702619 100644
--- a/src/osd/OSD.cc
+++ b/src/osd/OSD.cc
@@ -5463,7 +5463,7 @@ void OSD::do_command(Connection *con, ceph_tid_t tid, vector<string>& cmd, buffe
     for (vector<string>::iterator a = ++argsvec.begin(); a != argsvec.end(); ++a)
       args += " " + *a;
     osd_lock.Unlock();
-    cct->_conf->injectargs(args, &ss);
+    r = cct->_conf->injectargs(args, &ss);
     osd_lock.Lock();
   }
   else if (prefix == "cluster_log") {