RFR 8191278: MappedByteBuffer bulk access memory failures are not handled gracefully

[Jamsheed]

Hi Tobias

Hi Tobias,
On 14/03/19 1:56 PM, Tobias Hartmann wrote:
> Hi Jamsheed,
>
> On 13.03.19 06:48, Jamsheed wrote:
>> Thank you for the review.
>>
>> from the comments it says "StubRoutines are used by Compiled code and runtime system". and
>> StubRoutines::contains(pc) is expected be checked under code running in Java condition.
>>
>> missed adding is_Java check only in windows. later i had corrected it in fast failure handling
>> code[1], but missed putting it in the code under review.
>>
>> i presumed the stub routine[2] code  sigbus memory access error could happen only in case of Unsafe.
>> but will double check.
> If there's a bug in one of the other stubs, we could hit a SIGBUS there as well right? With your fix
> such a failure would be converted to an exception and therefore might go through unnoticed. I think
> the same applies to methods with has_unsafe_access() already but in this case we don't even check
> for unsafe access (because we would need to check the caller method of the stub).
very intermittent bug in compiler generating some invalid address can be 
issue, but this could happen for all has_unsafe_access() set nmethods too.

if it is frequently failing bug, there is high chance of getting 
attention, so probably adding a diagnostic option to generate core file 
in that case would work.

Best regards,

Jamsheed


>
> Best regards,
> Tobias