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[Guile-commits] 01/01: Fix abort_to_prompt bug if dynwind leave thunk ex
From: |
Andy Wingo |
Subject: |
[Guile-commits] 01/01: Fix abort_to_prompt bug if dynwind leave thunk expands the stack |
Date: |
Thu, 2 Jan 2020 07:30:23 -0500 (EST) |
wingo pushed a commit to branch master
in repository guile.
commit e3e3e691f817c2b37fbaec6f749cd4d7ce18d857
Author: Andy Wingo <address@hidden>
Date: Thu Jan 2 13:27:23 2020 +0100
Fix abort_to_prompt bug if dynwind leave thunk expands the stack
* libguile/vm.c (scm_i_vm_emergency_abort, abort_to_prompt): Unwinding
the dynwind stack can run dynwind leave thunks, which may expand the
stack, which may invalidate previously calculated SP / FP values.
(Re)calculate SP/FP after unwinding, to avoid writing to unmapped
memory. Fixes compile errors seen on Ubuntu and some other ports.
---
libguile/vm.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/libguile/vm.c b/libguile/vm.c
index 5899fa9..ab6a629 100644
--- a/libguile/vm.c
+++ b/libguile/vm.c
@@ -1,4 +1,4 @@
-/* Copyright 2001,2009-2015,2017-2019
+/* Copyright 2001,2009-2015,2017-2020
Free Software Foundation, Inc.
This file is part of Guile.
@@ -1360,9 +1360,6 @@ scm_i_vm_emergency_abort (SCM *tag_and_argv, size_t n)
abort ();
}
- fp = vp->stack_top - fp_offset;
- sp = vp->stack_top - sp_offset;
-
if (!(flags & SCM_F_DYNSTACK_PROMPT_ESCAPE_ONLY))
{
fprintf (stderr, "guile: fatal: emergency abort to non-linear prompt\n");
@@ -1374,6 +1371,9 @@ scm_i_vm_emergency_abort (SCM *tag_and_argv, size_t n)
/* Unwind. */
scm_dynstack_unwind (dynstack, prompt);
+ fp = vp->stack_top - fp_offset;
+ sp = vp->stack_top - sp_offset;
+
/* Continuation gets nargs+1 values: the one more is for the cont. */
sp = sp - nargs - 1;
@@ -1422,7 +1422,6 @@ abort_to_prompt (scm_thread *thread, uint8_t *saved_mra)
scm_misc_error ("abort", "Abort to unknown prompt", scm_list_1 (tag));
fp = vp->stack_top - fp_offset;
- sp = vp->stack_top - sp_offset;
/* Only reify if the continuation referenced in the handler. */
if (flags & SCM_F_DYNSTACK_PROMPT_ESCAPE_ONLY)
@@ -1439,6 +1438,10 @@ abort_to_prompt (scm_thread *thread, uint8_t *saved_mra)
/* Unwind. */
scm_dynstack_unwind (dynstack, prompt);
+ /* Recompute FP, as scm_dynstack_unwind may have expanded the stack. */
+ fp = vp->stack_top - fp_offset;
+ sp = vp->stack_top - sp_offset;
+
/* Continuation gets nargs+1 values: the one more is for the cont. */
sp = sp - nargs - 1;