RFR(S): 8069124 - runtime/NMT/MallocSiteHashOverflow.java failing in nightlies

[Christian Tornqvist]

Hi everyone,

 

Please review this small fix for an issue with NMT.

 

The failure was caused by reading random memory from the uninitialized
_hash_value, when this value happened to be 0x80000000, hash_to_index()
failed to negate the value and ended up with an index of -16:

 

#  Internal Error
(C:\\jprt\\T\\P1\\130630.ctornqvi\\s\\hotspot\\src\\share\\vm\\services\\mal
locSiteTable.cpp:139), pid=5680, tid=4928

#  assert(index >= 0) failed: Negative index -16

 

Reproduced the issue and verified the fix using a debugger. Ran vm.quick and
hotspot/test/:hotspot_jprt tests on Linux i586/x64 and Windows i586/x64 with
-XX:NativeMemoryTracking=detail

 

Webrev:

http://cr.openjdk.java.net/~ctornqvi/webrev/8069124/webrev.00/

 

Bug:

https://bugs.openjdk.java.net/browse/JDK-8069124

 

Thanks,

Christian