Author: Armin Rigo <[email protected]>
Branch:
Changeset: r86015:1d29fd069ef0
Date: 2016-08-04 17:40 +0200
http://bitbucket.org/pypy/pypy/changeset/1d29fd069ef0/
Log: Issue #2363: extracted a unit test that fails
diff --git a/rpython/memory/gc/test/test_object_pinning.py
b/rpython/memory/gc/test/test_object_pinning.py
--- a/rpython/memory/gc/test/test_object_pinning.py
+++ b/rpython/memory/gc/test/test_object_pinning.py
@@ -1,6 +1,7 @@
import py
from rpython.rtyper.lltypesystem import lltype, llmemory, llarena
from rpython.memory.gc.incminimark import IncrementalMiniMarkGC, WORD
+from rpython.memory.gc.incminimark import GCFLAG_VISITED
from test_direct import BaseDirectGCTest
T = lltype.GcForwardReference()
@@ -981,3 +982,56 @@
self.gc.major_collection_step() # should not crash reading 'ptr1'!
del self.gc.TEST_VISIT_SINGLE_STEP
+
+
+ def test_pin_bug2(self):
+ #
+ # * we have an old object A that points to a pinned object B
+ #
+ # * we unpin B
+ #
+ # * the next minor_collection() is done in STATE_MARKING==1
+ # when the object A is already black
+ #
+ # * _minor_collection() => _visit_old_objects_pointing_to_pinned()
+ # which will move the now-unpinned B out of the nursery, to B'
+ #
+ # At that point we need to take care of colors, otherwise we
+ # get a black object (A) pointing to a white object (B'),
+ # which must never occur.
+ #
+ ptrA = self.malloc(T)
+ ptrA.someInt = 42
+ adrA = llmemory.cast_ptr_to_adr(ptrA)
+ res = self.gc.pin(adrA)
+ assert res
+
+ ptrC = self.malloc(S)
+ self.stackroots.append(ptrC)
+
+ ptrB = self.malloc(S)
+ ptrB.data = ptrA
+ self.stackroots.append(ptrB)
+
+ self.gc.collect()
+ ptrB = self.stackroots[-1] # now old and outside the nursery
+ ptrC = self.stackroots[-2] # another random old object, traced later
+ adrB = llmemory.cast_ptr_to_adr(ptrB)
+
+ self.gc.minor_collection()
+ assert self.gc.gc_state == self.STATE_SCANNING
+ self.gc.major_collection_step()
+ assert self.gc.gc_state == self.STATE_MARKING
+ assert not (self.gc.header(adrB).tid & GCFLAG_VISITED) # not black yet
+
+ self.gc.TEST_VISIT_SINGLE_STEP = True
+ self.gc.major_collection_step()
+ assert self.gc.gc_state == self.STATE_MARKING
+ assert self.gc.header(adrB).tid & GCFLAG_VISITED # now black
+ # but ptrC is not traced yet, which is why we're still in STATE_MARKING
+ assert self.gc.old_objects_pointing_to_pinned.tolist() == [adrB]
+
+ self.gc.unpin(adrA)
+
+ self.gc.DEBUG = 2
+ self.gc.minor_collection()
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