From b8e682427a80798fec90dce31392beaf616c3e37 Mon Sep 17 00:00:00 2001 From: "Miss Islington (bot)" <31488909+miss-islington@users.noreply.github.com> Date: Wed, 14 Aug 2019 15:02:12 -0700 Subject: [PATCH] bpo-21131: Fix faulthandler.register(chain=True) stack (GH-15276) faulthandler now allocates a dedicated stack of SIGSTKSZ*2 bytes, instead of just SIGSTKSZ bytes. Calling the previous signal handler in faulthandler signal handler uses more than SIGSTKSZ bytes of stack memory on some platforms. (cherry picked from commit ac827edc493d3ac3f5b9b0cc353df1d4b418a9aa) Co-authored-by: Victor Stinner --- .../next/Library/2019-08-14-15-34-23.bpo-21131.0MMQRi.rst | 4 ++++ Modules/faulthandler.c | 6 +++++- 2 files changed, 9 insertions(+), 1 deletion(-) create mode 100644 Misc/NEWS.d/next/Library/2019-08-14-15-34-23.bpo-21131.0MMQRi.rst diff --git a/Misc/NEWS.d/next/Library/2019-08-14-15-34-23.bpo-21131.0MMQRi.rst b/Misc/NEWS.d/next/Library/2019-08-14-15-34-23.bpo-21131.0MMQRi.rst new file mode 100644 index 00000000000..d330aca1c17 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2019-08-14-15-34-23.bpo-21131.0MMQRi.rst @@ -0,0 +1,4 @@ +Fix ``faulthandler.register(chain=True)`` stack. faulthandler now allocates a +dedicated stack of ``SIGSTKSZ*2`` bytes, instead of just ``SIGSTKSZ`` bytes. +Calling the previous signal handler in faulthandler signal handler uses more +than ``SIGSTKSZ`` bytes of stack memory on some platforms. diff --git a/Modules/faulthandler.c b/Modules/faulthandler.c index f2b5a503f4e..7b325996b26 100644 --- a/Modules/faulthandler.c +++ b/Modules/faulthandler.c @@ -1325,7 +1325,11 @@ _PyFaulthandler_Init(int enable) * be able to allocate memory on the stack, even on a stack overflow. If it * fails, ignore the error. */ stack.ss_flags = 0; - stack.ss_size = SIGSTKSZ; + /* bpo-21131: allocate dedicated stack of SIGSTKSZ*2 bytes, instead of just + SIGSTKSZ bytes. Calling the previous signal handler in faulthandler + signal handler uses more than SIGSTKSZ bytes of stack memory on some + platforms. */ + stack.ss_size = SIGSTKSZ * 2; stack.ss_sp = PyMem_Malloc(stack.ss_size); if (stack.ss_sp != NULL) { err = sigaltstack(&stack, &old_stack);