archive/jdk
1
0
Fork 0
mirror of https://github.com/openjdk/jdk.git synced 2025-08-27 14:54:52 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

8050972: Concurrency problem in PcDesc cache

Browse source 
The entries of the PcDesc cache in nmethods are not declared as volatile, but they are accessed and modified by several threads concurrently.

Reviewed-by: kvn, dholmes, dcubed
This commit is contained in:
Martin Doerr 2014-07-17 10:21:31 +02:00
parent 33058abb3f
commit 1439e307db
1 changed files with 6 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

7
hotspot/src/share/vm/code/nmethod.hpp
View file

@ -69,7 +69,12 @@ class PcDescCache VALUE_OBJ_CLASS_SPEC {
friend class VMStructs; friend class VMStructs;
private: private:
enum { cache_size = 4 }; enum { cache_size = 4 };
PcDesc* _pc_descs[cache_size]; // last cache_size pc_descs found // The array elements MUST be volatile! Several threads may modify
// and read from the cache concurrently. find_pc_desc_internal has
// returned wrong results. C++ compiler (namely xlC12) may duplicate
// C++ field accesses if the elements are not volatile.
typedef PcDesc* PcDescPtr;
volatile PcDescPtr _pc_descs[cache_size]; // last cache_size pc_descs found
public: public:
PcDescCache() { debug_only(_pc_descs[0] = NULL); } PcDescCache() { debug_only(_pc_descs[0] = NULL); }
void reset_to(PcDesc* initial_pc_desc); void reset_to(PcDesc* initial_pc_desc);