From 8b787964e0a647caa0558b7c29ae501470d727d9 Mon Sep 17 00:00:00 2001 From: Victor Stinner Date: Wed, 4 Dec 2019 21:10:06 +0100 Subject: [PATCH] bpo-38965: Fix faulthandler._stack_overflow() on GCC 10 (GH-17467) Use the "volatile" keyword to prevent tail call optimization on any compiler, rather than relying on compiler specific pragma. --- .../2019-12-04-17-08-55.bpo-38965.yqax3m.rst | 3 +++ Modules/faulthandler.c | 16 ++++++---------- 2 files changed, 9 insertions(+), 10 deletions(-) create mode 100644 Misc/NEWS.d/next/Tests/2019-12-04-17-08-55.bpo-38965.yqax3m.rst diff --git a/Misc/NEWS.d/next/Tests/2019-12-04-17-08-55.bpo-38965.yqax3m.rst b/Misc/NEWS.d/next/Tests/2019-12-04-17-08-55.bpo-38965.yqax3m.rst new file mode 100644 index 00000000000..517a1371eac --- /dev/null +++ b/Misc/NEWS.d/next/Tests/2019-12-04-17-08-55.bpo-38965.yqax3m.rst @@ -0,0 +1,3 @@ +Fix test_faulthandler on GCC 10. Use the "volatile" keyword in +``faulthandler._stack_overflow()`` to prevent tail call optimization on any +compiler, rather than relying on compiler specific pragma. diff --git a/Modules/faulthandler.c b/Modules/faulthandler.c index d1280532ae2..b19401e94d8 100644 --- a/Modules/faulthandler.c +++ b/Modules/faulthandler.c @@ -1161,18 +1161,14 @@ faulthandler_fatal_error_py(PyObject *self, PyObject *args) #if defined(FAULTHANDLER_USE_ALT_STACK) #define FAULTHANDLER_STACK_OVERFLOW -#ifdef __INTEL_COMPILER - /* Issue #23654: Turn off ICC's tail call optimization for the - * stack_overflow generator. ICC turns the recursive tail call into - * a loop. */ -# pragma intel optimization_level 0 -#endif -static -uintptr_t +static uintptr_t stack_overflow(uintptr_t min_sp, uintptr_t max_sp, size_t *depth) { - /* allocate 4096 bytes on the stack at each call */ - unsigned char buffer[4096]; + /* Allocate (at least) 4096 bytes on the stack at each call. + + bpo-23654, bpo-38965: use volatile keyword to prevent tail call + optimization. */ + volatile unsigned char buffer[4096]; uintptr_t sp = (uintptr_t)&buffer; *depth += 1; if (sp < min_sp || max_sp < sp)