diff options
author | Ludovic Courtès <ludo@gnu.org> | 2018-06-29 22:28:48 +0200 |
---|---|---|
committer | Andy Wingo <wingo@pobox.com> | 2018-08-07 12:31:11 +0200 |
commit | 8840ee5a3ca48e1fc6b58c036467118ddf4dfcc4 (patch) | |
tree | 6d7b80c914cf384648704926d9fbf860064d85d0 /libguile/vm.c | |
parent | bab01b46edeec71ed1391a44d715741b418df0b0 (diff) | |
download | guile-8840ee5a3ca48e1fc6b58c036467118ddf4dfcc4.tar.gz |
vm: Fix stack-marking bug in multi-threaded programs.
Fixes <https://bugs.gnu.org/28211>.
* libguile/vm-engine.c (call, call_label, handle_interrupts): Add
'new_fp' variable; set the dynamic link and return address of the frame
at NEW_FP before setting 'vp->fp'. This fixes a bug whereby, in a
multi-threaded context, the stack-marking code could run after vp->fp
has been set but before its dynamic link has been set, leading the
stack-walking code in 'scm_i_vm_mark_stack' to exit early on.
Diffstat (limited to 'libguile/vm.c')
-rw-r--r-- | libguile/vm.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/libguile/vm.c b/libguile/vm.c index fa2f171a6..cc95a2c75 100644 --- a/libguile/vm.c +++ b/libguile/vm.c @@ -1013,7 +1013,7 @@ cons_rest (scm_thread *thread, uint32_t base) static void push_interrupt_frame (scm_thread *thread) { - union scm_vm_stack_element *old_fp; + union scm_vm_stack_element *old_fp, *new_fp; size_t old_frame_size = frame_locals_count (thread); SCM proc = scm_i_async_pop (thread); @@ -1024,13 +1024,14 @@ push_interrupt_frame (scm_thread *thread) alloc_frame (thread, old_frame_size + 3); old_fp = thread->vm.fp; - thread->vm.fp = SCM_FRAME_SLOT (old_fp, old_frame_size + 1); - SCM_FRAME_SET_DYNAMIC_LINK (thread->vm.fp, old_fp); + new_fp = SCM_FRAME_SLOT (old_fp, old_frame_size + 1); + SCM_FRAME_SET_DYNAMIC_LINK (new_fp, old_fp); /* Arrange to return to the same handle-interrupts opcode to handle any additional interrupts. */ - SCM_FRAME_SET_RETURN_ADDRESS (thread->vm.fp, thread->vm.ip); + SCM_FRAME_SET_RETURN_ADDRESS (new_fp, thread->vm.ip); + SCM_FRAME_LOCAL (new_fp, 0) = proc; - SCM_FRAME_LOCAL (thread->vm.fp, 0) = proc; + thread->vm.fp = new_fp; } struct return_to_continuation_data @@ -1402,7 +1403,6 @@ scm_call_n (SCM proc, SCM *argv, size_t nargs) SCM_FRAME_LOCAL (return_fp, 0) = vm_boot_continuation; vp->ip = (uint32_t *) vm_boot_continuation_code; - vp->fp = call_fp; SCM_FRAME_SET_RETURN_ADDRESS (call_fp, vp->ip); SCM_FRAME_SET_DYNAMIC_LINK (call_fp, return_fp); @@ -1410,6 +1410,8 @@ scm_call_n (SCM proc, SCM *argv, size_t nargs) for (i = 0; i < nargs; i++) SCM_FRAME_LOCAL (call_fp, i + 1) = argv[i]; + vp->fp = call_fp; + { jmp_buf registers; int resume; |