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bpo-38965: Fix faulthandler._stack_overflow() on GCC 10 (GH-17467)

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Use the "volatile" keyword to prevent tail call optimization
on any compiler, rather than relying on compiler specific pragma.
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Victor Stinner 2019-12-04 21:10:06 +01:00 • committed by GitHub
parent 7105319ada
commit 8b787964e0
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2 changed files with 9 additions and 10 deletions
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Misc/NEWS.d/next/Tests/2019-12-04-17-08-55.bpo-38965.yqax3m.rst Normal file
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@ -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.

16
Modules/faulthandler.c
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@ -1161,18 +1161,14 @@ faulthandler_fatal_error_py(PyObject *self, PyObject *args)
#if defined(FAULTHANDLER_USE_ALT_STACK) #if defined(FAULTHANDLER_USE_ALT_STACK)
#define FAULTHANDLER_STACK_OVERFLOW #define FAULTHANDLER_STACK_OVERFLOW
#ifdef __INTEL_COMPILER static uintptr_t
/* 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
stack_overflow(uintptr_t min_sp, uintptr_t max_sp, size_t *depth) stack_overflow(uintptr_t min_sp, uintptr_t max_sp, size_t *depth)
{ {
/* allocate 4096 bytes on the stack at each call */ /* Allocate (at least) 4096 bytes on the stack at each call.
unsigned char buffer[4096];
bpo-23654, bpo-38965: use volatile keyword to prevent tail call
optimization. */
volatile unsigned char buffer[4096];
uintptr_t sp = (uintptr_t)&buffer; uintptr_t sp = (uintptr_t)&buffer;
*depth += 1; *depth += 1;
if (sp < min_sp || max_sp < sp) if (sp < min_sp || max_sp < sp)