gh-151546: Fix stack limits on musl (#151548)

If the thread stack size is set by linker flags, pass the stack size
to Python/ceval.c via the new _Py_LINKER_THREAD_STACK_SIZE variable
to set Py_C_STACK_SIZE macro.

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-06-16-17-23-37.gh-issue-151546.LhiaZz.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-06-16-17-23-37.gh-issue-151546.LhiaZz.rst
new file mode 100644 (file)
index 0000000..af1c23b
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-06-16-17-23-37.gh-issue-151546.LhiaZz.rst
@@ -0,0 +1,3 @@
+Fix the stack limit check if Python is linked to musl (ex: Alpine Linux).
+Use the stack size set by the linker to compute the stack limits. Patch by
+Victor Stinner.

diff --git a/Python/ceval.c b/Python/ceval.c
index a9b31affca9890adb33fdb4ab06deb2211ffbf2a..d6dd7f9a82c4314a49b6f9a0a5063e72a7de4519 100644 (file)
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -49,7 +49,9 @@ _Py_ReachedRecursionLimitWithMargin(PyThreadState *tstate, int margin_count)
 #endif
 }
 
-#if defined(__s390x__)
+#if defined(_Py_LINKER_THREAD_STACK_SIZE)
+#  define Py_C_STACK_SIZE _Py_LINKER_THREAD_STACK_SIZE
+#elif defined(__s390x__)
 #  define Py_C_STACK_SIZE 320000
 #elif defined(_WIN32)
    // Don't define Py_C_STACK_SIZE, ask the O/S

diff --git a/configure b/configure
index 7608a0493b0ee62c2bb54fb09ed4b56d2187bfc3..7408fac738b8a398e6d334eea30ed012d9169c70 100755 (executable)
--- a/configure
+++ b/configure
@@ -9927,6 +9927,10 @@ printf "%s\n" "$ac_cv_thread_stack_size" >&6; }
 
     if test "$ac_cv_thread_stack_size" != "default" -a "$ac_cv_thread_stack_size" != "unknown"; then
         LDFLAGS="$LDFLAGS -Wl,-z,stack-size=$ac_cv_thread_stack_size"
+        # Stack size used by Python/ceval.c to set Py_C_STACK_SIZE
+
+printf "%s\n" "#define _Py_LINKER_THREAD_STACK_SIZE $ac_cv_thread_stack_size" >>confdefs.h
+
     fi
 fi
 

diff --git a/configure.ac b/configure.ac
index 020861b4c823759148b1cf952f8b19acd8efe2c8..dbc781b545dd362d342ea7a88ef4fefc8db68b2e 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -2507,6 +2507,9 @@ EOF
 
     if test "$ac_cv_thread_stack_size" != "default" -a "$ac_cv_thread_stack_size" != "unknown"; then
         LDFLAGS="$LDFLAGS -Wl,-z,stack-size=$ac_cv_thread_stack_size"
+        # Stack size used by Python/ceval.c to set Py_C_STACK_SIZE
+        AC_DEFINE_UNQUOTED([_Py_LINKER_THREAD_STACK_SIZE], [$ac_cv_thread_stack_size],
+                  [Thread stack size set by the linker (in bytes).])
     fi
 fi
 

diff --git a/pyconfig.h.in b/pyconfig.h.in
index dc2404fe85fa232810834540ffdf54436d2e86f9..999a55a5efd0fb0467b9c43966040c245f110f70 100644 (file)
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -2088,6 +2088,9 @@
 /* Define if you have the 'PR_SET_VMA_ANON_NAME' constant. */
 #undef _Py_HAVE_PR_SET_VMA_ANON_NAME
 
+/* Thread stack size set by the linker (in bytes). */
+#undef _Py_LINKER_THREAD_STACK_SIZE
+
 /* Define to 1 if the machine stack grows down (default); 0 if it grows up. */
 #undef _Py_STACK_GROWS_DOWN