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authorMagnus Lång <[email protected]>2016-05-23 15:41:31 +0200
committerMagnus Lång <[email protected]>2016-07-06 16:08:20 +0200
commitf0131c58c42a286c8b3f611b47106393a37197b6 (patch)
treecaefc37baef32b065e69f23cc363a83ff70dcd12 /erts/emulator/hipe/hipe_gc.c
parent3b409021a70427bb2fe3834707edf822b6afce2d (diff)
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check_process_code: Sweep HiPE stack for literals
Because check_process_code neglected checking the HiPE stack for references to the literal area, such references would survive the purge and subsequent deletion of a module and its literal area. These dangling references would then cause incorrect behaviour or even hard crashes of the VM. By simply adding a scan of the HiPE stack to check_process_code and erts_garbage_collect_literals, this problem is fixed. In order to support full stack walks without deleting the graylimit trap, a new stack walking interface function, nstack_walk_init_sdesc_ignore_trap() was introduced.
Diffstat (limited to 'erts/emulator/hipe/hipe_gc.c')
-rw-r--r--erts/emulator/hipe/hipe_gc.c119
1 files changed, 119 insertions, 0 deletions
diff --git a/erts/emulator/hipe/hipe_gc.c b/erts/emulator/hipe/hipe_gc.c
index 566c65882e..68c65dea27 100644
--- a/erts/emulator/hipe/hipe_gc.c
+++ b/erts/emulator/hipe/hipe_gc.c
@@ -237,3 +237,122 @@ void gensweep_nstack(Process *p, Eterm **ptr_old_htop, Eterm **ptr_n_htop)
}
abort();
}
+
+Eterm *sweep_literals_nstack(Process *p, Eterm *old_htop, char *area,
+ Uint area_size)
+{
+ /* known nstack walk state */
+ Eterm *nsp;
+ Eterm *nsp_end;
+ const struct sdesc *sdesc;
+ /* arch-specific nstack walk state */
+ struct nstack_walk_state walk_state;
+
+ ASSERT(!p->hipe.gc_is_unsafe);
+
+ if (!p->hipe.nstack) {
+ ASSERT(!p->hipe.nsp && !p->hipe.nstend);
+ return old_htop;
+ }
+ if (!nstack_walk_init_check(p))
+ return old_htop;
+
+ ASSERT(p->hipe.nsp && p->hipe.nstend);
+ nsp = nstack_walk_nsp_begin(p);
+ nsp_end = nstack_walk_nsp_end(p);
+ sdesc = nstack_walk_init_sdesc_ignore_trap(p, &walk_state);
+
+ while (!nstack_walk_nsp_reached_end(nsp, nsp_end)) {
+ unsigned long ra;
+ unsigned sdesc_size = nstack_walk_frame_size(sdesc);
+ unsigned i = 0;
+ unsigned mask = sdesc->livebits[0];
+ for (;;) {
+ if (mask & 1) {
+ Eterm *nsp_i = nstack_walk_frame_index(nsp, i);
+ Eterm gval = *nsp_i;
+ if (is_boxed(gval)) {
+ Eterm *ptr = boxed_val(gval);
+ Eterm val = *ptr;
+ if (IS_MOVED_BOXED(val)) {
+ ASSERT(is_boxed(val));
+ *nsp_i = val;
+ } else if (ErtsInArea(ptr, area, area_size)) {
+ MOVE_BOXED(ptr, val, old_htop, nsp_i);
+ }
+ } else if (is_list(gval)) {
+ Eterm *ptr = list_val(gval);
+ Eterm val = *ptr;
+ if (IS_MOVED_CONS(val)) {
+ *nsp_i = ptr[1];
+ } else if (ErtsInArea(ptr, area, area_size)) {
+ MOVE_CONS(ptr, val, old_htop, nsp_i);
+ }
+ }
+ }
+ if (++i >= sdesc_size)
+ break;
+ if (i & 31)
+ mask >>= 1;
+ else
+ mask = sdesc->livebits[i >> 5];
+ }
+ ra = nstack_walk_frame_ra(nsp, sdesc);
+ if (ra == (unsigned long)nbif_stack_trap_ra)
+ ra = (unsigned long)p->hipe.ngra;
+ sdesc = hipe_find_sdesc(ra);
+ nsp = nstack_walk_next_frame(nsp, sdesc_size);
+ }
+ return old_htop;
+}
+
+int
+nstack_any_heap_ref_ptrs(Process *rp, char* mod_start, Uint mod_size)
+{
+ Eterm *nsp;
+ Eterm *nsp_end;
+ const struct sdesc *sdesc;
+ /* arch-specific nstack walk state */
+ struct nstack_walk_state walk_state;
+
+ ASSERT(!rp->hipe.gc_is_unsafe);
+
+ if (!rp->hipe.nstack || !nstack_walk_init_check(rp)) return 0;
+ ASSERT(rp->hipe.nsp && rp->hipe.nstend);
+ nsp = nstack_walk_nsp_begin(rp);
+ nsp_end = nstack_walk_nsp_end(rp);
+ sdesc = nstack_walk_init_sdesc_ignore_trap(rp, &walk_state);
+
+ while (!nstack_walk_nsp_reached_end(nsp, nsp_end)) {
+ unsigned long ra;
+ unsigned sdesc_size = nstack_walk_frame_size(sdesc);
+ unsigned i = 0;
+ unsigned mask = sdesc->livebits[0];
+ for (;;) {
+ if (mask & 1) {
+ Eterm *nsp_i = nstack_walk_frame_index(nsp, i);
+ Eterm val = *nsp_i;
+ switch (primary_tag(val)) {
+ case TAG_PRIMARY_BOXED:
+ case TAG_PRIMARY_LIST:
+ if (ErtsInArea(val, mod_start, mod_size)) {
+ return 1;
+ }
+ break;
+ }
+ }
+ if (++i >= sdesc_size)
+ break;
+ if (i & 31)
+ mask >>= 1;
+ else
+ mask = sdesc->livebits[i >> 5];
+ }
+ ra = nstack_walk_frame_ra(nsp, sdesc);
+ if (ra == (unsigned long)nbif_stack_trap_ra)
+ ra = (unsigned long)rp->hipe.ngra;
+ sdesc = hipe_find_sdesc(ra);
+ nsp = nstack_walk_next_frame(nsp, sdesc_size);
+ }
+ return 0;
+}