diff --git a/Ubiquitous/XiZi_AIoT/hardkernel/arch/arm/armv7-a/cortex-a9/preboot_for_imx6q-sabrelite/config.mk b/Ubiquitous/XiZi_AIoT/hardkernel/arch/arm/armv7-a/cortex-a9/preboot_for_imx6q-sabrelite/config.mk
index 9f7d2a2df..e1bd49d00 100644
--- a/Ubiquitous/XiZi_AIoT/hardkernel/arch/arm/armv7-a/cortex-a9/preboot_for_imx6q-sabrelite/config.mk
+++ b/Ubiquitous/XiZi_AIoT/hardkernel/arch/arm/armv7-a/cortex-a9/preboot_for_imx6q-sabrelite/config.mk
@@ -1,6 +1,6 @@
 export CROSS_COMPILE ?= arm-none-eabi-
 export DEVICE = -march=armv7-a -mtune=cortex-a9 -mfpu=vfpv3-d16 -ftree-vectorize -ffast-math -mfloat-abi=softfp
-export CFLAGS := $(DEVICE) -Wall -O0 -g -gdwarf-2
+export CFLAGS := $(DEVICE) -Wall -O2 -g -gdwarf-2  -Wnull-dereference -Waddress -Warray-bounds -Wchar-subscripts -Wimplicit-int -Wimplicit-function-declaration -Wcomment -Wformat -Wmissing-braces -Wnonnull -Wparentheses -Wpointer-sign -Wreturn-type -Wsequence-point -Wstrict-aliasing -Wstrict-overflow=1 -Wswitch -Wtrigraphs -Wuninitialized -Wunknown-pragmas -Wunused-function -Wunused-label -Wunused-value -Wunused-variable -Wunused-function
 export AFLAGS := -c $(DEVICE) -x assembler-with-cpp -D__ASSEMBLY__ -gdwarf-2
 # export LFLAGS := $(DEVICE) -Wl,-Map=XiZi-imx6q-sabrelite.map,-cref,-u,_boot_start -T $(KERNEL_ROOT)/hardkernel/arch/arm/armv7-a/cortex-a9/preboot_for_imx6q-sabrelite/nxp_imx6q_sabrelite.lds
 export LFLAGS := $(DEVICE) --specs=nosys.specs -Wl,-Map=XiZi-imx6q-sabrelite.map,-cref,-u,_boot_start -T $(KERNEL_ROOT)/hardkernel/arch/arm/armv7-a/cortex-a9/preboot_for_imx6q-sabrelite/nxp_imx6q_sabrelite.lds
diff --git a/Ubiquitous/XiZi_AIoT/hardkernel/intr/arm/armv7-a/cortex-a9/error_debug.c b/Ubiquitous/XiZi_AIoT/hardkernel/intr/arm/armv7-a/cortex-a9/error_debug.c
index af072ff91..a96d80440 100644
--- a/Ubiquitous/XiZi_AIoT/hardkernel/intr/arm/armv7-a/cortex-a9/error_debug.c
+++ b/Ubiquitous/XiZi_AIoT/hardkernel/intr/arm/armv7-a/cortex-a9/error_debug.c
@@ -125,20 +125,22 @@ void iabort_reason(struct trapframe* r)
 void handle_undefined_instruction(struct trapframe* tf)
 {
     // unimplemented trap handler
-    xizi_enter_kernel();
     ERROR("undefined instruction at %x\n", tf->pc);
+    xizi_enter_kernel();
     panic("");
 }
 
 void handle_reserved(void)
 {
     // unimplemented trap handler
+    ERROR("Unimplemented Reserved\n");
     xizi_enter_kernel();
-    panic("Unimplemented Reserved\n");
+    panic("");
 }
 
 void handle_fiq(void)
 {
+    ERROR("Unimplemented FIQ\n");
     xizi_enter_kernel();
-    panic("Unimplemented FIQ\n");
+    panic("");
 }
\ No newline at end of file
diff --git a/Ubiquitous/XiZi_AIoT/kernel_actracer/actracer.c b/Ubiquitous/XiZi_AIoT/kernel_actracer/actracer.c
index 7d9a6a6ac..d790e0344 100644
--- a/Ubiquitous/XiZi_AIoT/kernel_actracer/actracer.c
+++ b/Ubiquitous/XiZi_AIoT/kernel_actracer/actracer.c
@@ -367,8 +367,9 @@ static void trace_locate_inner(struct TraceTag* target, struct TraceTag* const p
     // p_trace_meta: TRACER_OWNER, VT_FS or other.
     //      TRACER_OWNER: path: "", name: "dir name"
     //      other:  path: "", name: "file name"
-    if (!p_trace_meta) {
+    if (p_trace_meta == NULL) {
         DEBUG("trace_locate, not found\n");
+        return;
     }
     target->type = p_trace_meta->type;
     target->meta = p_trace_meta;
diff --git a/Ubiquitous/XiZi_AIoT/kernel_actracer/actracer_mem_chunk.c b/Ubiquitous/XiZi_AIoT/kernel_actracer/actracer_mem_chunk.c
index 44909c21e..01d64fa4a 100644
--- a/Ubiquitous/XiZi_AIoT/kernel_actracer/actracer_mem_chunk.c
+++ b/Ubiquitous/XiZi_AIoT/kernel_actracer/actracer_mem_chunk.c
@@ -105,6 +105,9 @@ static struct tracer_mem_chunk* tracer_get_mem_chunk_cache(uint32_t chunk_id)
 struct tracer_mem_chunk* tracer_mem_chunk_read(uint32_t chunk_id)
 {
     struct tracer_mem_chunk* b = tracer_get_mem_chunk_cache(chunk_id);
+    if (b == NULL) {
+        return NULL;
+    }
     if (!(b->flag & TRACER_MEM_CHUNK_VALID)) {
         tracer_mem_chunk_sync(b);
         b->flag |= TRACER_MEM_CHUNK_VALID;
@@ -137,6 +140,9 @@ static void tracer_mem_chunk_zero(uint32_t chunk_id)
     assert(chunk_id >= 0 && chunk_id < tracer_mem_chunk_syner.nr_mem_chunks);
     struct tracer_mem_chunk* tracer_mem_chunk = NULL;
     tracer_mem_chunk = tracer_mem_chunk_read(chunk_id);
+    if (tracer_mem_chunk == NULL) {
+        return;
+    }
     memset(tracer_mem_chunk->data, 0, tracer_mem_chunk_syner.mem_chunk_size);
     tracer_mem_chunk_write(tracer_mem_chunk);
     tracer_mem_chunk_release(tracer_mem_chunk);
diff --git a/Ubiquitous/XiZi_AIoT/services/app/Makefile b/Ubiquitous/XiZi_AIoT/services/app/Makefile
index 69b548d0e..a0df04ce6 100644
--- a/Ubiquitous/XiZi_AIoT/services/app/Makefile
+++ b/Ubiquitous/XiZi_AIoT/services/app/Makefile
@@ -1,12 +1,12 @@
 ifeq ($(BOARD), imx6q-sabrelite)
 toolchain ?= arm-none-eabi-
 user_ldflags = --specs=nosys.specs -Wl,-Map=user.map,-cref -N
-cflags = -std=c11 -march=armv7-a -mtune=cortex-a9 -nostdlib -nodefaultlibs -mfloat-abi=soft -fno-pic -static -fno-builtin -fno-strict-aliasing -Wall -ggdb -Wno-unused -Werror -fno-omit-frame-pointer -fno-stack-protector -fno-pie -no-pie
+cflags = -std=c11 -O2 -march=armv7-a -mtune=cortex-a9 -nostdlib -nodefaultlibs -mfloat-abi=soft -fno-pic -static -fno-builtin -fno-strict-aliasing -Wall -ggdb -Wno-unused -Werror -fno-omit-frame-pointer -fno-stack-protector -fno-pie -no-pie
 endif
 ifeq ($(BOARD), zynq7000-zc702)
 toolchain ?= arm-xilinx-eabi-
 user_ldflags = -Wl,--start-group,-lgcc,-lc,--end-group -N
-cflags = -std=c11 -march=armv7-a -mtune=cortex-a9 -nostdlib -nodefaultlibs -mfloat-abi=soft -fno-pic -static -fno-builtin -fno-strict-aliasing -Wall -ggdb -Wno-unused -Werror -fno-omit-frame-pointer -fno-stack-protector -fno-pie
+cflags = -std=c11 -O2 -march=armv7-a -mtune=cortex-a9 -nostdlib -nodefaultlibs -mfloat-abi=soft -fno-pic -static -fno-builtin -fno-strict-aliasing -Wall -ggdb -Wno-unused -Werror -fno-omit-frame-pointer -fno-stack-protector -fno-pie
 board_specs = stub.o
 #cflags = -Wall -g -std=c11 
 endif
diff --git a/Ubiquitous/XiZi_AIoT/softkernel/syscall/sys_close_session.c b/Ubiquitous/XiZi_AIoT/softkernel/syscall/sys_close_session.c
index 3299f24bf..bcc921bee 100644
--- a/Ubiquitous/XiZi_AIoT/softkernel/syscall/sys_close_session.c
+++ b/Ubiquitous/XiZi_AIoT/softkernel/syscall/sys_close_session.c
@@ -75,6 +75,9 @@ int sys_close_session(struct TaskMicroDescriptor* cur_task, struct Session* sess
     }
 
     /* close this session */
+    if (session_backend == NULL) {
+        return -1;
+    }
     if (UNLIKELY(session_backend->client_side.closed && session_backend->server_side.closed) && LIKELY(session_valid)) {
         xizi_share_page_manager.delete_share_pages(session_backend);
     }
diff --git a/Ubiquitous/XiZi_AIoT/softkernel/task/task.c b/Ubiquitous/XiZi_AIoT/softkernel/task/task.c
index 76b3fe9d3..59a83cfda 100644
--- a/Ubiquitous/XiZi_AIoT/softkernel/task/task.c
+++ b/Ubiquitous/XiZi_AIoT/softkernel/task/task.c
@@ -233,7 +233,7 @@ static void _scheduler(struct SchedulerRightGroup right_group)
         next_task = NULL;
         /* find next runnable task */
         assert(cur_cpu()->task == NULL);
-        if (next_task_emergency != NULL && next_task->state == READY) {
+        if (next_task_emergency != NULL && next_task_emergency->state == READY) {
             next_task = next_task_emergency;
         } else {
             next_task = xizi_task_manager.next_runnable_task();
diff --git a/Ubiquitous/XiZi_AIoT/softkernel/trap/abort_handler.c b/Ubiquitous/XiZi_AIoT/softkernel/trap/abort_handler.c
index 693f6a987..af806507a 100644
--- a/Ubiquitous/XiZi_AIoT/softkernel/trap/abort_handler.c
+++ b/Ubiquitous/XiZi_AIoT/softkernel/trap/abort_handler.c
@@ -58,11 +58,11 @@ __attribute__((optimize("O0"))) void dabort_handler(struct trapframe* r)
         panic("data abort exception\n");
     }
 
-    xizi_enter_kernel();
-
     struct TaskMicroDescriptor* cur_task = cur_cpu()->task;
     ERROR("dabort in user space: %s\n", cur_task->name);
     dabort_reason(r);
+
+    xizi_enter_kernel();
     sys_exit(cur_task);
     assert(cur_cpu()->task == NULL);
     context_switch(&cur_task->main_thread.context, cur_cpu()->scheduler);
@@ -78,11 +78,11 @@ __attribute__((optimize("O0"))) void iabort_handler(struct trapframe* r)
         panic("kernel prefetch abort exception\n");
     }
 
-    xizi_enter_kernel();
-
     struct TaskMicroDescriptor* cur_task = cur_cpu()->task;
     ERROR("iabort in user space: %s\n", cur_task->name);
     iabort_reason(r);
+
+    xizi_enter_kernel();
     sys_exit(cur_task);
     assert(cur_cpu()->task == NULL);
     context_switch(&cur_task->main_thread.context, cur_cpu()->scheduler);
diff --git a/Ubiquitous/XiZi_AIoT/softkernel/trap/default_irq_handler.c b/Ubiquitous/XiZi_AIoT/softkernel/trap/default_irq_handler.c
index 2010d9c22..5a4233b8c 100644
--- a/Ubiquitous/XiZi_AIoT/softkernel/trap/default_irq_handler.c
+++ b/Ubiquitous/XiZi_AIoT/softkernel/trap/default_irq_handler.c
@@ -95,13 +95,13 @@ intr_leave_interrupt:
     xizi_leave_kernel();
 }
 
-void xizi_enter_kernel()
+__attribute__((always_inline)) inline void xizi_enter_kernel()
 {
     /// @warning trampoline is responsible for closing interrupt
     spinlock_lock(&whole_kernel_lock);
 }
 
-inline bool xizi_try_enter_kernel()
+__attribute__((always_inline)) inline bool xizi_try_enter_kernel()
 {
     /// @warning trampoline is responsible for closing interrupt
     if (spinlock_try_lock(&whole_kernel_lock)) {
@@ -111,7 +111,7 @@ inline bool xizi_try_enter_kernel()
     return false;
 }
 
-inline void xizi_leave_kernel()
+__attribute__((always_inline)) inline void xizi_leave_kernel()
 {
     /// @warning trampoline is responsible for eabling interrupt by using user's state register
     spinlock_unlock(&whole_kernel_lock);