RFR (XS) 8232778: Shenandoah: SBSA::arraycopy_prologue checks wrong register
Aleksey Shipilev
shade at redhat.com
Tue Oct 22 11:48:15 UTC 2019
Bug:
https://bugs.openjdk.java.net/browse/JDK-8232778
Fix:
diff -r 24d411cb3a90 src/hotspot/cpu/aarch64/gc/shenandoah/shenandoahBarrierSetAssembler_aarch64.cpp
--- a/src/hotspot/cpu/aarch64/gc/shenandoah/shenandoahBarrierSetAssembler_aarch64.cpp Tue Oct 22
08:57:41 2019 +0200
+++ b/src/hotspot/cpu/aarch64/gc/shenandoah/shenandoahBarrierSetAssembler_aarch64.cpp Tue Oct 22
13:39:05 2019 +0200
@@ -58,7 +58,7 @@
Address gc_state(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
__ ldrb(rscratch1, gc_state);
if (dest_uninitialized) {
- __ tbz(rscratch2, ShenandoahHeap::HAS_FORWARDED_BITPOS, done);
+ __ tbz(rscratch1, ShenandoahHeap::HAS_FORWARDED_BITPOS, done);
} else {
__ mov(rscratch2, ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::MARKING);
__ tst(rscratch1, rscratch2);
The load happens into rscratch1, yet we are testing rscratch2. I think this silently breaks
arraycopy to-space guarantees, as rscratch2 may contain garbage.
Testing: aarch64 hotspot_gc_shenandoah
--
Thanks,
-Aleksey
More information about the hotspot-gc-dev
mailing list