Bug#1139593: python3.14: Please build with -fno-thread-jumps instead of -O1 on m68k

John Paul Adrian Glaubitz <[email protected]> Wed, 10 Jun 2026 08:23:58 +0200
Newsgroups gmane.linux.debian.ports.68k
Message-ID <178107263855.2534791.7931581935156473457.reportbug__22658.5673679196$1781072857$gmane$org@login1.physik.fu-berlin.de>
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Source: python3.14
Version: 3.14.5-1
Severity: normal
Tags: patch
X-Debbugs-Cc: [email protected]
User: [email protected]
Usertags: m68k

Hello,

after lots of testing, it was discovered that the lockup problem of CPython
on m68k is caused by the -fthread-jumps optimization. [1]

Thus, it's therefore not necessary to build the whole interpretor with -O1,
it's enough to turn that optimization off with -fno-thread-jumps.

Could you just pass -fno-thread-jumps in debian/rules to CFLAGS instead of
-O1?

--- debian/rules.orig   2026-05-11 03:38:08.000000000 +0200
+++ debian/rules        2026-06-10 00:40:31.672179962 +0200
@@ -204,8 +204,8 @@
 endif
 
 ifneq (,$(filter $(DEB_HOST_ARCH), m68k))
-    OPT_CFLAGS += $(filter-out -O%,$(DPKG_CFLAGS)) -O1
-    OPT_PIE_CFLAGS += $(filter-out -O%,$(DPKG_PIE_CFLAGS)) -O1
+    OPT_CFLAGS += -fno-thread-jumps
+    OPT_PIE_CFLAGS += -fno-thread-jumps
 endif
 
 ifeq ($(DEB_HOST_GNU_TYPE),$(DEB_BUILD_GNU_TYPE))

Thanks,
Adrian

--
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
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--- debian/rules.orig	2026-05-11 03:38:08.000000000 +0200
+++ debian/rules	2026-06-10 00:40:31.672179962 +0200
@@ -204,8 +204,8 @@
 endif
 
 ifneq (,$(filter $(DEB_HOST_ARCH), m68k))
-    OPT_CFLAGS += $(filter-out -O%,$(DPKG_CFLAGS)) -O1
-    OPT_PIE_CFLAGS += $(filter-out -O%,$(DPKG_PIE_CFLAGS)) -O1
+    OPT_CFLAGS += -fno-thread-jumps
+    OPT_PIE_CFLAGS += -fno-thread-jumps
 endif
 
 ifeq ($(DEB_HOST_GNU_TYPE),$(DEB_BUILD_GNU_TYPE))

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