From 2450bc617489c953f1472dbcba6c98fb1081e352 Mon Sep 17 00:00:00 2001
From: Balasubramania Pillai <balu.pillai@bird.com>
Date: Wed, 11 Feb 2026 17:36:12 -0500
Subject: [PATCH 01/11] TASK-194243 debug double unlock

---
 src/ldo.c    |  3 +++
 src/thrlua.h | 16 ++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/src/ldo.c b/src/ldo.c
index a64e320..7b3b270 100644
--- a/src/ldo.c
+++ b/src/ldo.c
@@ -69,6 +69,9 @@ void luaD_throw (lua_State *L, int errcode) {
     LUAI_THROW(L, L->errorJmp);
   }
   else {
+    thrlua_log(L, DCRITICAL,
+      "luaD_throw: no error handler, errcode=%d, L=%p, invoking panic",
+      errcode, (void *)L);
     L->status = cast_byte(errcode);
     if (G(L)->panic) {
       resetstack(L, errcode);
diff --git a/src/thrlua.h b/src/thrlua.h
index 3f39d8f..6d69bcc 100644
--- a/src/thrlua.h
+++ b/src/thrlua.h
@@ -254,6 +254,22 @@ extern void lua_do_longjmp(luai_jmpbuf env, int val)
 #define LUAI_TRY_END(L) \
   (L)->errorJmp = lj.previous; \
   if (lj.status) { \
+    /* Log the error and re-throw path for diagnostics. */ \
+    thrlua_log((L), DCRITICAL, \
+      "LUAI_TRY_END: error status=%d in TRY block at %s:%d, " \
+      "re-throwing with %s outer handler, L=%p", \
+      lj.status, lj.file, lj.line, \
+      lj.previous ? "an" : "NO", (void *)(L)); \
+    /* Re-acquire the lock before re-throwing.  The LUAI_TRY_FINALLY \
+     * block has already called lua_unlock(), but luaD_throw() expects \
+     * the lock to be held: if there is an outer error handler its \
+     * FINALLY will lua_unlock(), and if there is no outer handler the \
+     * panic path in luaD_throw() calls lua_unlock() explicitly.  \
+     * Without this re-lock we double-unlock the pthread mutex which \
+     * is undefined behavior and corrupts the mutex on Linux/glibc, \
+     * causing every subsequent lua_lock() on this lua_State to fail \
+     * with EINVAL and abort(). */ \
+    lua_lock((L)); \
     luaD_throw((L), lj.status); \
   } \
 } while(0)

From d5b2b1bb2027c1a984280e4828f0dd9b3eada154 Mon Sep 17 00:00:00 2001
From: Balasubramania Pillai <balu.pillai@bird.com>
Date: Thu, 12 Feb 2026 15:41:03 -0500
Subject: [PATCH 02/11] TASK-194243 fix double unlock

---
 src/ldo.c    | 12 +++++++++++-
 src/thrlua.h | 10 ----------
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/ldo.c b/src/ldo.c
index 7b3b270..4e8abb7 100644
--- a/src/ldo.c
+++ b/src/ldo.c
@@ -75,7 +75,17 @@ void luaD_throw (lua_State *L, int errcode) {
     L->status = cast_byte(errcode);
     if (G(L)->panic) {
       resetstack(L, errcode);
-      lua_unlock(L);
+      /* Do NOT call lua_unlock(L) here.  When luaD_throw is reached
+       * via LUAI_TRY_END re-throw, the LUAI_TRY_FINALLY block has
+       * already run and the lock state depends on the call site:
+       * some FINALLY blocks call lua_unlock (lapi.c, lauxlib.c) while
+       * others call lua_lock (ldo.c callhook/precall).  Unconditionally
+       * unlocking here caused a double-unlock that corrupted the
+       * pthread mutex on Linux/glibc, making every subsequent
+       * lua_lock() on this lua_State fail with EINVAL and abort().
+       * All direct callers of luaD_throw (lmem.c, ldebug.c, lundump.c,
+       * llex.c) always have an outer errorJmp so they never reach
+       * this panic branch. */
       G(L)->panic(L);
     }
     exit(EXIT_FAILURE);
diff --git a/src/thrlua.h b/src/thrlua.h
index 6d69bcc..b275f39 100644
--- a/src/thrlua.h
+++ b/src/thrlua.h
@@ -260,16 +260,6 @@ extern void lua_do_longjmp(luai_jmpbuf env, int val)
       "re-throwing with %s outer handler, L=%p", \
       lj.status, lj.file, lj.line, \
       lj.previous ? "an" : "NO", (void *)(L)); \
-    /* Re-acquire the lock before re-throwing.  The LUAI_TRY_FINALLY \
-     * block has already called lua_unlock(), but luaD_throw() expects \
-     * the lock to be held: if there is an outer error handler its \
-     * FINALLY will lua_unlock(), and if there is no outer handler the \
-     * panic path in luaD_throw() calls lua_unlock() explicitly.  \
-     * Without this re-lock we double-unlock the pthread mutex which \
-     * is undefined behavior and corrupts the mutex on Linux/glibc, \
-     * causing every subsequent lua_lock() on this lua_State to fail \
-     * with EINVAL and abort(). */ \
-    lua_lock((L)); \
     luaD_throw((L), lj.status); \
   } \
 } while(0)

From 8d605612fcab2a413581bc438634f34541ec30d4 Mon Sep 17 00:00:00 2001
From: Balasubramania Pillai <balu.pillai@bird.com>
Date: Fri, 13 Feb 2026 08:42:35 -0500
Subject: [PATCH 03/11] TASK-194243 fix logging

---
 src/lapi.c   |  4 ++++
 src/ldo.c    |  2 +-
 src/thrlua.h | 16 ++++++++++------
 3 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/src/lapi.c b/src/lapi.c
index bb07ca8..ee02ef2 100644
--- a/src/lapi.c
+++ b/src/lapi.c
@@ -1233,6 +1233,10 @@ LUA_API int lua_error (lua_State *L) {
   lua_lock(L);
   LUAI_TRY_BLOCK(L) {
     api_checknelems(L, 1);
+    {
+      const char *msg = lua_isstring(L, -1) ? lua_tostring(L, -1) : "(non-string error)";
+      thrlua_log(L, DCRITICAL, "lua_error called: %s\n", msg);
+    }
     luaG_errormsg(L);
   } LUAI_TRY_FINALLY(L) {
     lua_unlock(L);
diff --git a/src/ldo.c b/src/ldo.c
index 4e8abb7..9b2db4c 100644
--- a/src/ldo.c
+++ b/src/ldo.c
@@ -70,7 +70,7 @@ void luaD_throw (lua_State *L, int errcode) {
   }
   else {
     thrlua_log(L, DCRITICAL,
-      "luaD_throw: no error handler, errcode=%d, L=%p, invoking panic",
+      "luaD_throw: no error handler, errcode=%d, L=%p, invoking panic\n",
       errcode, (void *)L);
     L->status = cast_byte(errcode);
     if (G(L)->panic) {
diff --git a/src/thrlua.h b/src/thrlua.h
index b275f39..aa8a217 100644
--- a/src/thrlua.h
+++ b/src/thrlua.h
@@ -254,12 +254,16 @@ extern void lua_do_longjmp(luai_jmpbuf env, int val)
 #define LUAI_TRY_END(L) \
   (L)->errorJmp = lj.previous; \
   if (lj.status) { \
-    /* Log the error and re-throw path for diagnostics. */ \
-    thrlua_log((L), DCRITICAL, \
-      "LUAI_TRY_END: error status=%d in TRY block at %s:%d, " \
-      "re-throwing with %s outer handler, L=%p", \
-      lj.status, lj.file, lj.line, \
-      lj.previous ? "an" : "NO", (void *)(L)); \
+    /* Only log when there is NO outer handler -- that is the \
+     * dangerous path that hits luaD_throw's panic branch. \
+     * Normal error propagation (with an outer handler) is \
+     * high-frequency and must not be logged. */ \
+    if (!lj.previous) { \
+      thrlua_log((L), DCRITICAL, \
+        "LUAI_TRY_END: error status=%d in TRY block at %s:%d, " \
+        "re-throwing with NO outer handler, L=%p\n", \
+        lj.status, lj.file, lj.line, (void *)(L)); \
+    } \
     luaD_throw((L), lj.status); \
   } \
 } while(0)

From 6a8c24c2cfc00ebb376ef5fdb3462d41de42c9e9 Mon Sep 17 00:00:00 2001
From: Balasubramania Pillai <balu.pillai@bird.com>
Date: Fri, 13 Feb 2026 08:52:05 -0500
Subject: [PATCH 04/11] TASK-194243 fix logging

---
 src/lapi.c   | 4 ----
 src/ldebug.c | 5 +++++
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/lapi.c b/src/lapi.c
index ee02ef2..bb07ca8 100644
--- a/src/lapi.c
+++ b/src/lapi.c
@@ -1233,10 +1233,6 @@ LUA_API int lua_error (lua_State *L) {
   lua_lock(L);
   LUAI_TRY_BLOCK(L) {
     api_checknelems(L, 1);
-    {
-      const char *msg = lua_isstring(L, -1) ? lua_tostring(L, -1) : "(non-string error)";
-      thrlua_log(L, DCRITICAL, "lua_error called: %s\n", msg);
-    }
     luaG_errormsg(L);
   } LUAI_TRY_FINALLY(L) {
     lua_unlock(L);
diff --git a/src/ldebug.c b/src/ldebug.c
index ec60a37..98907cb 100644
--- a/src/ldebug.c
+++ b/src/ldebug.c
@@ -631,6 +631,11 @@ void luaG_errormsg (lua_State *L) {
     incr_top(L);
     luaD_call(L, L->top - 2, 1);  /* call it */
   }
+  {
+    const char *msg = (L->top > L->base && ttisstring(L->top - 1))
+      ? svalue(L->top - 1) : "(non-string error)";
+    thrlua_log(L, DCRITICAL, "luaG_errormsg: %s\n", msg);
+  }
   luaD_throw(L, LUA_ERRRUN);
 }
 

From 4fbebf52d7ec4c83048d1079636a4a29daa6bc1b Mon Sep 17 00:00:00 2001
From: Balasubramania Pillai <balu.pillai@bird.com>
Date: Fri, 13 Feb 2026 10:10:21 -0500
Subject: [PATCH 05/11] TASK-194243 tune logging

---
 src/lapi.c   | 4 ++++
 src/ldebug.c | 7 ++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/lapi.c b/src/lapi.c
index bb07ca8..ace347d 100644
--- a/src/lapi.c
+++ b/src/lapi.c
@@ -1232,6 +1232,10 @@ LUA_API int lua_gc (lua_State *L, int what, int data) {
 LUA_API int lua_error (lua_State *L) {
   lua_lock(L);
   LUAI_TRY_BLOCK(L) {
+    {
+//      const char *msg = lua_isstring(L, -1) ? lua_tostring(L, -1) : "(non-string error)";
+//      thrlua_log(L, DCRITICAL, "lua_error called: %s\n", msg);
+    }
     api_checknelems(L, 1);
     luaG_errormsg(L);
   } LUAI_TRY_FINALLY(L) {
diff --git a/src/ldebug.c b/src/ldebug.c
index 98907cb..34103f8 100644
--- a/src/ldebug.c
+++ b/src/ldebug.c
@@ -631,7 +631,12 @@ void luaG_errormsg (lua_State *L) {
     incr_top(L);
     luaD_call(L, L->top - 2, 1);  /* call it */
   }
-  {
+  /* Only log when there is no error handler -- that means the
+   * subsequent luaD_throw will hit the panic branch.  When
+   * L->errorJmp is set the error will be caught by pcall/xpcall
+   * and is part of normal control flow (e.g. lua-aws uses pcall
+   * for method-existence checks). */
+  if (!L->errorJmp) {
     const char *msg = (L->top > L->base && ttisstring(L->top - 1))
       ? svalue(L->top - 1) : "(non-string error)";
     thrlua_log(L, DCRITICAL, "luaG_errormsg: %s\n", msg);

From 657cda24cea876fcd03b9828fc43ccf060f9f343 Mon Sep 17 00:00:00 2001
From: Balasubramania Pillai <balu.pillai@bird.com>
Date: Fri, 13 Feb 2026 10:39:42 -0500
Subject: [PATCH 06/11] TASK-194243 tune logging

---
 src/lapi.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/lapi.c b/src/lapi.c
index ace347d..aabfc20 100644
--- a/src/lapi.c
+++ b/src/lapi.c
@@ -1233,10 +1233,11 @@ LUA_API int lua_error (lua_State *L) {
   lua_lock(L);
   LUAI_TRY_BLOCK(L) {
     {
-//      const char *msg = lua_isstring(L, -1) ? lua_tostring(L, -1) : "(non-string error)";
-//      thrlua_log(L, DCRITICAL, "lua_error called: %s\n", msg);
+      const char *msg = lua_isstring(L, -1) ? lua_tostring(L, -1) : "(non-string error)";
+      thrlua_log(L, DCRITICAL, "lua_error called 1: %s\n", msg);
     }
     api_checknelems(L, 1);
+      thrlua_log(L, DCRITICAL, "lua_error called 2\n", );
     luaG_errormsg(L);
   } LUAI_TRY_FINALLY(L) {
     lua_unlock(L);

From e1bf5186ccc0753e6bdae5af05c3c7e48401e5bd Mon Sep 17 00:00:00 2001
From: Balasubramania Pillai <balu.pillai@bird.com>
Date: Fri, 13 Feb 2026 10:43:55 -0500
Subject: [PATCH 07/11] TASK-194243 tune logging

---
 src/lapi.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/src/lapi.c b/src/lapi.c
index aabfc20..60125d1 100644
--- a/src/lapi.c
+++ b/src/lapi.c
@@ -1232,12 +1232,10 @@ LUA_API int lua_gc (lua_State *L, int what, int data) {
 LUA_API int lua_error (lua_State *L) {
   lua_lock(L);
   LUAI_TRY_BLOCK(L) {
-    {
       const char *msg = lua_isstring(L, -1) ? lua_tostring(L, -1) : "(non-string error)";
       thrlua_log(L, DCRITICAL, "lua_error called 1: %s\n", msg);
-    }
     api_checknelems(L, 1);
-      thrlua_log(L, DCRITICAL, "lua_error called 2\n", );
+      thrlua_log(L, DCRITICAL, "lua_error called %s\n", "end");
     luaG_errormsg(L);
   } LUAI_TRY_FINALLY(L) {
     lua_unlock(L);

From ca92e6ccaa17af34532082c2ecce15fb054f310f Mon Sep 17 00:00:00 2001
From: Balasubramania Pillai <balu.pillai@bird.com>
Date: Fri, 13 Feb 2026 11:29:41 -0500
Subject: [PATCH 08/11] TASK-194243 tune logging

---
 src/lapi.c   |  8 +++++---
 src/ldebug.c | 10 +++-------
 2 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/src/lapi.c b/src/lapi.c
index 60125d1..334fa0b 100644
--- a/src/lapi.c
+++ b/src/lapi.c
@@ -1232,10 +1232,12 @@ LUA_API int lua_gc (lua_State *L, int what, int data) {
 LUA_API int lua_error (lua_State *L) {
   lua_lock(L);
   LUAI_TRY_BLOCK(L) {
-      const char *msg = lua_isstring(L, -1) ? lua_tostring(L, -1) : "(non-string error)";
-      thrlua_log(L, DCRITICAL, "lua_error called 1: %s\n", msg);
     api_checknelems(L, 1);
-      thrlua_log(L, DCRITICAL, "lua_error called %s\n", "end");
+    {
+      const char *msg = lua_isstring(L, -1) ? lua_tostring(L, -1) : "(non-string error)";
+      thrlua_log(L, DCRITICAL, "lua_error (%s): %s\n",
+        L->errorJmp ? "caught" : "unhandled", msg);
+    }
     luaG_errormsg(L);
   } LUAI_TRY_FINALLY(L) {
     lua_unlock(L);
diff --git a/src/ldebug.c b/src/ldebug.c
index 34103f8..3b40aff 100644
--- a/src/ldebug.c
+++ b/src/ldebug.c
@@ -631,15 +631,11 @@ void luaG_errormsg (lua_State *L) {
     incr_top(L);
     luaD_call(L, L->top - 2, 1);  /* call it */
   }
-  /* Only log when there is no error handler -- that means the
-   * subsequent luaD_throw will hit the panic branch.  When
-   * L->errorJmp is set the error will be caught by pcall/xpcall
-   * and is part of normal control flow (e.g. lua-aws uses pcall
-   * for method-existence checks). */
-  if (!L->errorJmp) {
+  {
     const char *msg = (L->top > L->base && ttisstring(L->top - 1))
       ? svalue(L->top - 1) : "(non-string error)";
-    thrlua_log(L, DCRITICAL, "luaG_errormsg: %s\n", msg);
+    thrlua_log(L, DCRITICAL, "luaG_errormsg (%s): %s\n",
+      L->errorJmp ? "caught" : "unhandled", msg);
   }
   luaD_throw(L, LUA_ERRRUN);
 }

From 7f9f8047eca67faa9a56dd37a6223e9601d94323 Mon Sep 17 00:00:00 2001
From: Balasubramania Pillai <balu.pillai@bird.com>
Date: Fri, 13 Feb 2026 12:03:47 -0500
Subject: [PATCH 09/11] TASK-194243 tune logging

---
 src/lstrlib.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/lstrlib.c b/src/lstrlib.c
index 6693eb3..35bfd81 100644
--- a/src/lstrlib.c
+++ b/src/lstrlib.c
@@ -138,8 +138,16 @@ static int str_dump (lua_State *L) {
   luaL_checktype(L, 1, LUA_TFUNCTION);
   lua_settop(L, 1);
   luaL_buffinit(L,&b);
-  if (lua_dump(L, writer, &b) != 0)
-    luaL_error(L, "unable to dump given function");
+  if (lua_dump(L, writer, &b) != 0) {
+    lua_Debug ar;
+    lua_pushvalue(L, 1);
+    lua_getinfo(L, ">nS", &ar);
+    luaL_error(L, "unable to dump given function (%s '%s' defined at %s:%d)",
+      ar.what ? ar.what : "?",
+      ar.name ? ar.name : "(anonymous)",
+      ar.short_src ? ar.short_src : "?",
+      ar.linedefined);
+  }
   luaL_pushresult(&b);
   return 1;
 }

From 1aa55d7b69355df58c7983970509ff0cfafdb323 Mon Sep 17 00:00:00 2001
From: Balasubramania Pillai <balu.pillai@bird.com>
Date: Fri, 13 Feb 2026 12:30:14 -0500
Subject: [PATCH 10/11] TASK-194243 tune logging

---
 src/lapi.c   | 13 +++++++++----
 src/ldebug.c |  5 ++---
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/lapi.c b/src/lapi.c
index 334fa0b..de9719a 100644
--- a/src/lapi.c
+++ b/src/lapi.c
@@ -1233,10 +1233,15 @@ LUA_API int lua_error (lua_State *L) {
   lua_lock(L);
   LUAI_TRY_BLOCK(L) {
     api_checknelems(L, 1);
-    {
-      const char *msg = lua_isstring(L, -1) ? lua_tostring(L, -1) : "(non-string error)";
-      thrlua_log(L, DCRITICAL, "lua_error (%s): %s\n",
-        L->errorJmp ? "caught" : "unhandled", msg);
+    if (!L->errorJmp) {
+      /* Use raw accessors (ttisstring/svalue) instead of the public API
+       * (lua_isstring/lua_tostring).  lua_isstring returns true for
+       * numbers, and lua_tostring -> lua_tolstring calls lua_lock for
+       * number-to-string conversion, which would deadlock since we
+       * already hold the lock from lua_error's lua_lock above. */
+      StkId o = L->top - 1;
+      const char *msg = ttisstring(o) ? svalue(o) : "(non-string error)";
+      thrlua_log(L, DCRITICAL, "lua_error (unhandled): %s\n", msg);
     }
     luaG_errormsg(L);
   } LUAI_TRY_FINALLY(L) {
diff --git a/src/ldebug.c b/src/ldebug.c
index 3b40aff..e17b490 100644
--- a/src/ldebug.c
+++ b/src/ldebug.c
@@ -631,11 +631,10 @@ void luaG_errormsg (lua_State *L) {
     incr_top(L);
     luaD_call(L, L->top - 2, 1);  /* call it */
   }
-  {
+  if (!L->errorJmp) {
     const char *msg = (L->top > L->base && ttisstring(L->top - 1))
       ? svalue(L->top - 1) : "(non-string error)";
-    thrlua_log(L, DCRITICAL, "luaG_errormsg (%s): %s\n",
-      L->errorJmp ? "caught" : "unhandled", msg);
+    thrlua_log(L, DCRITICAL, "luaG_errormsg (unhandled): %s\n", msg);
   }
   luaD_throw(L, LUA_ERRRUN);
 }

From fbf904bf9d6cef840217b7ce301d9a7320cc90fb Mon Sep 17 00:00:00 2001
From: Balasubramania Pillai <balu.pillai@bird.com>
Date: Fri, 13 Feb 2026 12:51:30 -0500
Subject: [PATCH 11/11] TASK-194243 tune logging

---
 src/lapi.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/lapi.c b/src/lapi.c
index de9719a..cdfa967 100644
--- a/src/lapi.c
+++ b/src/lapi.c
@@ -1233,8 +1233,13 @@ LUA_API int lua_error (lua_State *L) {
   lua_lock(L);
   LUAI_TRY_BLOCK(L) {
     api_checknelems(L, 1);
-    if (!L->errorJmp) {
-      /* Use raw accessors (ttisstring/svalue) instead of the public API
+    if (!lj.previous) {
+      /* Log only when there is no outer error handler -- i.e. the error
+       * will ultimately reach the panic branch.  We check lj.previous
+       * (not L->errorJmp) because LUAI_TRY_BLOCK already set
+       * L->errorJmp = &lj, so L->errorJmp is always non-NULL here.
+       *
+       * Use raw accessors (ttisstring/svalue) instead of the public API
        * (lua_isstring/lua_tostring).  lua_isstring returns true for
        * numbers, and lua_tostring -> lua_tolstring calls lua_lock for
        * number-to-string conversion, which would deadlock since we