From c1bd3aa131d89abc128e2e9ddc24fd80c86c203e Mon Sep 17 00:00:00 2001
From: Christian Cunningham <cc@localhost>
Date: Sat, 19 Mar 2022 10:30:45 -0700
Subject: Fixed Deadlock Mechanism
---
src/util/mutex.c | 30 ++++++++++++++++++++++--------
1 file changed, 22 insertions(+), 8 deletions(-)
(limited to 'src')
diff --git a/src/util/mutex.c b/src/util/mutex.c
index 0525a3e..0a47a35 100644
--- a/src/util/mutex.c
+++ b/src/util/mutex.c
@@ -53,32 +53,46 @@ unsigned char delete_mutex(struct Mutex* m)
return 0;
}
+void uart_mutexes(void)
+{
+ struct Entry* entry = mutex_manager.used.start.next;
+ while (entry->entry_type == VALUE_ENTRY)
+ {
+ struct Mutex* m = entry->value;
+ uart_hex(m);
+ uart_char(' ');
+ uart_hex(m->pid);
+ uart_char(' ');
+ uart_hexn(m->addr);
+ entry = entry->next;
+ }
+}
+
void lock_mutex(struct Mutex* m)
{
struct Thread* rthread = scheduler.rthread;
unsigned long rpid = rthread->pid;
unsigned long mode = getmode() & 0x1F;
if (mode == 0x10) {
- sys1(SYS_LOCK, m);
// Find this mutex
struct Entry* mentry = find_value(m, &mutex_manager.used);
// If it is not a managed mutex, break away
if (mentry == 0)
return;
- // Get the next entry
- mentry = mentry->next->next;
+ struct Entry* entry = mutex_manager.used.start.next;
// Ensure this thread locks all mutexs sequentially
// To avoid a deadlock
- while (mentry->entry_type == VALUE_ENTRY) {
- struct Mutex* vmutex = mentry->value;
+ while (entry->entry_type == VALUE_ENTRY) {
+ struct Mutex* vmutex = entry->value;
// If this thread had locked it
// Toggle the lock to prevent deadlock
if (vmutex->pid == rpid) {
- sys1(SYS_UNLOCK, m);
- sys1(SYS_LOCK, m);
+ sys1(SYS_UNLOCK, vmutex);
+ sys1(SYS_LOCK, vmutex);
}
- mentry = mentry->next;
+ entry = entry->next;
}
+ sys1(SYS_LOCK, m);
}
}
--
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