RFR (S): 8175340: Possible invalid memory accesses due to ciMethodData::bci_to_data() returning NULL
zoltan.majo at oracle.com
Wed Mar 8 09:57:04 UTC 2017
please review the fix for 8175340.
The method ciMethodData::bci_to_data() can return NULL instead of a
valid ciProfileData*. Some users of the ciProfileData returned by
bci_to_data() do not check if the returned value is NULL, which can
result in an invalid memory accesses.
The issue has never happened in practice. While working on the issue,
however, I experimented with a VM version that had asserts in
Parse::branch_prediction and to Parse::dynamic_branch_prediction
checking that bci_to_data() is not NULL. I was able to trigger some of
the asserts I added by running the VM with -XX:-ProfileInterpreter
-XX:-TieredCompilation. (The asserts are not part of the patch sent out
The fix I propose is simple: Check if bci_to_data() is NULL, if yes, do
not use profiling information / generate profiling code.
The fix passes JPRT and RBT testing.
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