diff --git a/kernel/hal/x86_64/intr.c b/kernel/hal/x86_64/intr.c
index cd08598..20e8a1e 100644
--- a/kernel/hal/x86_64/intr.c
+++ b/kernel/hal/x86_64/intr.c
@@ -215,13 +215,13 @@ void intr_handleintr(IntrStackFrame *frame) {
         break;
       case INTR_IRQBASE+1:
         int32_t c = ps2kb_intr();
-        intr_eoi(frame->trapnum - INTR_IRQBASE);
         if (c >= 0) {
-          uint8_t *bytes = (uint8_t *)&c;
-          for (size_t i = 0; i < sizeof(c); i++) {
-            rbuf_push(&PS2KB_BUF.rbuf, bytes[i]);
-          }
+          uint8_t b = c;
+          spinlock_acquire(&PS2KB_BUF.spinlock);
+          rbuf_push(&PS2KB_BUF.rbuf, b);
+          spinlock_release(&PS2KB_BUF.spinlock);
         }
+        intr_eoi(frame->trapnum - INTR_IRQBASE);
         break;
     }
   } else if (frame->trapnum == 0x80) {
diff --git a/kernel/proc/ps2kbproc/ps2kbproc.c b/kernel/proc/ps2kbproc/ps2kbproc.c
index 747a331..f1f665f 100644
--- a/kernel/proc/ps2kbproc/ps2kbproc.c
+++ b/kernel/proc/ps2kbproc/ps2kbproc.c
@@ -22,26 +22,18 @@ void ps2kbproc_init(Proc *proc) {
 
 void ps2kbproc_fn(void) {
   for (;;) {
-    int32_t kbchr = 0;
-    uint8_t *buf = (uint8_t *)&kbchr;
-    size_t total = 0;
+    uint8_t b = 0;
     spinlock_acquire(&PS2KB_BUF.spinlock);
-    for (size_t i = 0; i < sizeof(kbchr); i++) {
-      if (rbuf_pop(&PS2KB_BUF.rbuf, &buf[i]) < 0) {
-        break;
-      }
-      total++;
-    }
-    spinlock_release(&PS2KB_BUF.spinlock);
-    if (total == sizeof(kbchr)) {
+    if (rbuf_pop(&PS2KB_BUF.rbuf, &b) == 0) {
       spinlock_acquire(&PS2KBPROC->bcast_pipes.spinlock);
       IpcPipe *head = PS2KBPROC->bcast_pipes.list;
       while (head != NULL) {
-        ipc_pipewrite(head, (uint8_t *)&kbchr, sizeof(kbchr));
+        ipc_pipewrite(head, &b, 1);
         head = head->next;
       }
       spinlock_release(&PS2KBPROC->bcast_pipes.spinlock);
     }
+    spinlock_release(&PS2KB_BUF.spinlock);
   }
 }
 
diff --git a/user/tb/main.c b/user/tb/main.c
index bb47b70..67570ff 100644
--- a/user/tb/main.c
+++ b/user/tb/main.c
@@ -109,11 +109,11 @@ void do_mode_interactive(void) {
     cursor = 0;
     string_memset(linebuf, 0, LINEBUF_MAX);
 
-    int32_t kbchr = 0;
+    uint8_t b = 0;
     for (;;) {
-      int32_t nrd = ipcpipe(PID, IPCPIPE_IN, IPCPIPE_READ, (uint8_t *)&kbchr, sizeof(kbchr));
+      int32_t nrd = ipcpipe(PID, IPCPIPE_IN, IPCPIPE_READ, &b, 1);
       if (nrd > 0) {
-        switch (kbchr) {
+        switch (b) {
           case C('C'):
           case 0xE9:
             uprintf("\n");
@@ -126,15 +126,13 @@ void do_mode_interactive(void) {
             break;
         }
 
-        char chr = kbchr & 0xFF;
-
-        if (chr == '\n') {
+        if (b == '\n') {
           break;
         }
 
-        if (string_chr_isascii(chr) && chr != 0 && cursor < LINEBUF_MAX) {
-          linebuf[cursor++] = chr;
-          uprintf("%c", chr);
+        if (string_chr_isascii(b) && b != 0 && cursor < LINEBUF_MAX) {
+          linebuf[cursor++] = b;
+          uprintf("%c", b);
         }
       }
     }