From a87da59cebb15df408b037632f889f32e5d830ce Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Trung=20L=C3=AA?= <8@tle.id.au>
Date: Wed, 25 Mar 2026 11:42:36 +1100
Subject: [PATCH] Fix ogg_sync_pageout hook

The commit 2df07b59 has caused regression
---
 src/include/alternate.h |  2 ++
 src/mallochook.c        |  6 +++++-
 src/tools/alternate.c   | 23 ++++++++++++++++++++++-
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/src/include/alternate.h b/src/include/alternate.h
index 322635e37b..4eabf0e304 100644
--- a/src/include/alternate.h
+++ b/src/include/alternate.h
@@ -11,6 +11,8 @@ void* getAlternate(void* addr);
 void addAlternate(void* addr, void* alt);
 void addCheckAlternate(void* addr, void* alt);
 void cleanAlternate(void);
+void suppressAlternate(void* addr);
+void unsuppressAlternate(void* addr);
 #ifdef HAVE_ALTJUMP
 uintptr_t getAlternateJump(void* addr, int is32bits);
 #endif
diff --git a/src/mallochook.c b/src/mallochook.c
index 50ba713063..76b807e26b 100644
--- a/src/mallochook.c
+++ b/src/mallochook.c
@@ -881,8 +881,12 @@ static void*     ogg_page_body_copy = NULL;
 
 static int my_ogg_sync_pageout_32(void* oy, void* og)
 {
-    // Call the original emulated ogg_sync_pageout
+    // Suppress the alternate for the duration of the call to avoid
+    // infinite recursion: RunFunctionFmt -> EmuRun -> getAlternate
+    // would redirect back to this hook without suppression.
+    suppressAlternate((void*)real_ogg_sync_pageout_32);
     int ret = (int)RunFunctionFmt(real_ogg_sync_pageout_32, "pp", oy, og);
+    unsuppressAlternate((void*)real_ogg_sync_pageout_32);
 
     if(ret > 0 && og) {
         // ogg_sync_pageout succeeded — og now has pointers into oy->data
diff --git a/src/tools/alternate.c b/src/tools/alternate.c
index 7597f63724..67110a27ae 100644
--- a/src/tools/alternate.c
+++ b/src/tools/alternate.c
@@ -20,9 +20,17 @@ typedef struct {
 KHASH_MAP_INIT_INT64(alternate, my_alternate_t)
 static kh_alternate_t *my_alternates = NULL;
 
+// Per-address suppression: when set, getAlternate/hasAlternate/getAlternateJump
+// will return "no alternate" for this specific address.  Used by hooks that need
+// to call through to the original emulated function via RunFunctionFmt without
+// triggering infinite recursion (EmuRun applies getAlternate every iteration).
+static uintptr_t alternate_suppress = 0;
+
 int hasAlternate(void* addr) {
     if(!my_alternates)
         return 0;
+    if((uintptr_t)addr == alternate_suppress)
+        return 0;
     khint_t k = kh_get(alternate, my_alternates, (uintptr_t)addr);
     if(k==kh_end(my_alternates))
         return 0;
@@ -32,6 +40,8 @@ int hasAlternate(void* addr) {
 void* getAlternate(void* addr) {
     if(!my_alternates)
         return addr;
+    if((uintptr_t)addr == alternate_suppress)
+        return addr;
     khint_t k = kh_get(alternate, my_alternates, (uintptr_t)addr);
     if(k!=kh_end(my_alternates))
         return kh_value(my_alternates, k).addr;
@@ -53,6 +63,15 @@ void addAlternate(void* addr, void* alt) {
     #endif
 }
 
+void suppressAlternate(void* addr) {
+    alternate_suppress = (uintptr_t)addr;
+}
+
+void unsuppressAlternate(void* addr) {
+    (void)addr;
+    alternate_suppress = 0;
+}
+
 void addCheckAlternate(void* addr, void* alt) {
     if(!hasAlternate(addr))
         addAlternate(addr, alt);
@@ -70,6 +89,8 @@ void cleanAlternate() {
 uintptr_t getAlternateJump(void* addr, int is32bits) {
     if(!my_alternates)
         return 0;
+    if((uintptr_t)addr == alternate_suppress)
+        return 0;
     khint_t k = kh_get(alternate, my_alternates, (uintptr_t)addr);
     if(k!=kh_end(my_alternates)) {
         uintptr_t ret = kh_value(my_alternates, k).jump;
@@ -78,4 +99,4 @@ uintptr_t getAlternateJump(void* addr, int is32bits) {
     }
     return 0;
 }
-#endif
\ No newline at end of file
+#endif