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vm: Fix stack-marking bug in multi-threaded programs.

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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.
This commit is contained in:
Ludovic Courtès 2018-06-29 22:28:48 +02:00
parent b87068eee7
commit 23af45e248
1 changed files with 15 additions and 12 deletions
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27
libguile/vm-engine.c
View file

@ -548,7 +548,7 @@ VM_NAME (scm_i_thread *thread, struct scm_vm *vp,
VM_DEFINE_OP (1, call, "call", OP2 (X8_F24, X8_C24))
{
scm_t_uint32 proc, nlocals;
union scm_vm_stack_element *old_fp;
union scm_vm_stack_element *old_fp, *new_fp;
UNPACK_24 (op, proc);
UNPACK_24 (ip[1], nlocals);
@ -556,9 +556,10 @@ VM_NAME (scm_i_thread *thread, struct scm_vm *vp,
PUSH_CONTINUATION_HOOK ();
old_fp = vp->fp;
vp->fp = SCM_FRAME_SLOT (old_fp, proc - 1);
SCM_FRAME_SET_DYNAMIC_LINK (vp->fp, old_fp);
SCM_FRAME_SET_RETURN_ADDRESS (vp->fp, ip + 2);
new_fp = SCM_FRAME_SLOT (old_fp, proc - 1);
SCM_FRAME_SET_DYNAMIC_LINK (new_fp, old_fp);
SCM_FRAME_SET_RETURN_ADDRESS (new_fp, ip + 2);
vp->fp = new_fp;
RESET_FRAME (nlocals);
@ -586,7 +587,7 @@ VM_NAME (scm_i_thread *thread, struct scm_vm *vp,
{
scm_t_uint32 proc, nlocals;
scm_t_int32 label;
union scm_vm_stack_element *old_fp;
union scm_vm_stack_element *old_fp, *new_fp;
UNPACK_24 (op, proc);
UNPACK_24 (ip[1], nlocals);
@ -595,9 +596,10 @@ VM_NAME (scm_i_thread *thread, struct scm_vm *vp,
PUSH_CONTINUATION_HOOK ();
old_fp = vp->fp;
vp->fp = SCM_FRAME_SLOT (old_fp, proc - 1);
SCM_FRAME_SET_DYNAMIC_LINK (vp->fp, old_fp);
SCM_FRAME_SET_RETURN_ADDRESS (vp->fp, ip + 3);
new_fp = SCM_FRAME_SLOT (old_fp, proc - 1);
SCM_FRAME_SET_DYNAMIC_LINK (new_fp, old_fp);
SCM_FRAME_SET_RETURN_ADDRESS (new_fp, ip + 3);
vp->fp = new_fp;
RESET_FRAME (nlocals);
@ -3893,7 +3895,7 @@ VM_NAME (scm_i_thread *thread, struct scm_vm *vp,
NEXT (1);
{
union scm_vm_stack_element *old_fp;
union scm_vm_stack_element *old_fp, *new_fp;
size_t old_frame_size = FRAME_LOCALS_COUNT ();
SCM proc = scm_i_async_pop (thread);
@ -3907,9 +3909,10 @@ VM_NAME (scm_i_thread *thread, struct scm_vm *vp,
handle-interrupts opcode to handle any additional
interrupts. */
old_fp = vp->fp;
vp->fp = SCM_FRAME_SLOT (old_fp, old_frame_size + 1);
SCM_FRAME_SET_DYNAMIC_LINK (vp->fp, old_fp);
SCM_FRAME_SET_RETURN_ADDRESS (vp->fp, ip);
new_fp = SCM_FRAME_SLOT (old_fp, old_frame_size + 1);
SCM_FRAME_SET_DYNAMIC_LINK (new_fp, old_fp);
SCM_FRAME_SET_RETURN_ADDRESS (new_fp, ip);
vp->fp = new_fp;
SP_SET (0, proc);