From 68f6aef2159df9c87642d22d549060338f23632f Mon Sep 17 00:00:00 2001
From: kamkow1 <kamkow256@gmail.com>
Date: Mon, 2 Mar 2026 00:12:08 +0100
Subject: [PATCH] Fix checking if cpu->proc_current != NULL

---
 aux/qemu_amd64.sh   |  2 +-
 kernel/amd64/intr.c |  9 +++++---
 kernel/proc/proc.c  | 53 +++++++++------------------------------------
 kernel/proc/proc.h  |  1 -
 4 files changed, 17 insertions(+), 48 deletions(-)

diff --git a/aux/qemu_amd64.sh b/aux/qemu_amd64.sh
index e229c5f..cca9eab 100755
--- a/aux/qemu_amd64.sh
+++ b/aux/qemu_amd64.sh
@@ -2,4 +2,4 @@
 
 set -x
 
-qemu-system-x86_64 -M q35 -m 4G -serial stdio -enable-kvm -cdrom mop3.iso -smp 1 $@
+qemu-system-x86_64 -M q35 -m 4G -serial stdio -enable-kvm -cdrom mop3.iso -smp 4 $@
diff --git a/kernel/amd64/intr.c b/kernel/amd64/intr.c
index 7ad534e..dd35e74 100644
--- a/kernel/amd64/intr.c
+++ b/kernel/amd64/intr.c
@@ -190,12 +190,15 @@ void intr_handler (void* stack_ptr) {
     intr_exception (regs);
   } else {
     spin_lock (&thiscpu->lock);
+
     struct proc* proc_current = thiscpu->proc_current;
-    spin_lock (&proc_current->lock);
 
-    memcpy (&proc_current->pdata.regs, regs, sizeof (struct saved_regs));
+    if (proc_current != NULL) {
+      spin_lock (&proc_current->lock);
+      memcpy (&proc_current->pdata.regs, regs, sizeof (struct saved_regs));
+      spin_unlock (&proc_current->lock);
+    }
 
-    spin_unlock (&proc_current->lock);
     spin_unlock (&thiscpu->lock);
 
     lapic_eoi ();
diff --git a/kernel/proc/proc.c b/kernel/proc/proc.c
index 0fa9fdc..3b71786 100644
--- a/kernel/proc/proc.c
+++ b/kernel/proc/proc.c
@@ -238,51 +238,8 @@ static struct proc* proc_find_sched (struct cpu* cpu) {
   return NULL;
 }
 
-static void proc_reap (struct reschedule_ctx* rctx) {
-  struct proc* proc = NULL;
-  struct list_node_link* reap_list = NULL;
-
-  spin_lock (&proc_tree_lock);
-
-  struct rb_node_link* node;
-  rbtree_first (&proc_tree, node);
-
-  while (node) {
-    struct rb_node_link* next;
-    rbtree_next (node, next);
-    proc = rbtree_entry (node, struct proc, proc_tree_link);
-
-    node = next;
-
-    spin_lock (&proc->lock);
-
-    if (proc->state == PROC_DEAD) {
-      list_append (reap_list, &proc->reap_link);
-      rbtree_delete (&proc_tree, &proc->proc_tree_link);
-    }
-
-    spin_unlock (&proc->lock);
-  }
-
-  spin_unlock (&proc_tree_lock);
-
-  struct list_node_link *reap_link, *reap_link_tmp;
-  list_foreach (reap_list, reap_link, reap_link_tmp) {
-    proc = list_entry (reap_link, struct proc, reap_link);
-
-    list_remove (reap_list, &proc->reap_link);
-
-    DEBUG ("cleanup PID %d\n", proc->pid);
-    proc_cleanup (proc, rctx);
-  }
-}
-
 void proc_sched (void) {
   int s_cycles = atomic_fetch_add (&sched_cycles, 1);
-  struct reschedule_ctx rctx = {0};
-
-  if (s_cycles % SCHED_REAP_FREQ == 0)
-    proc_reap (&rctx);
 
   struct proc* next = NULL;
   struct cpu* cpu = thiscpu;
@@ -322,6 +279,16 @@ void proc_kill (struct proc* proc, struct reschedule_ctx* rctx) {
   spin_unlock (&proc->lock);
   spin_unlock (&cpu->lock);
 
+  spin_lock (&proc_tree_lock);
+  spin_lock (&proc->lock);
+
+  rbtree_delete (&proc_tree, &proc->proc_tree_link);
+
+  spin_unlock (&proc->lock);
+  spin_unlock (&proc_tree_lock);
+
+  proc_cleanup (proc, rctx);
+
   rctx_insert_cpu (rctx, cpu);
 
   DEBUG ("killed PID %d\n", proc->pid);
diff --git a/kernel/proc/proc.h b/kernel/proc/proc.h
index 4b20391..9992388 100644
--- a/kernel/proc/proc.h
+++ b/kernel/proc/proc.h
@@ -35,7 +35,6 @@ struct proc {
   struct rb_node_link proc_tree_link;
   struct rb_node_link procgroup_memb_tree_link;
   struct list_node_link cpu_run_q_link;
-  struct list_node_link reap_link;
   struct list_node_link* sq_entries;
   struct procgroup* procgroup;
   struct proc_platformdata pdata;