RFR: 8206267: Unsafe publication of StubCodeDesc leads to crashes
aph at redhat.com
Tue Jul 3 15:16:04 UTC 2018
On 07/03/2018 03:57 PM, Aleksey Shipilev wrote:
> On 07/03/2018 04:31 PM, aph wrote:
>> The StubCodeDesc constructor is unsychronized. However, it runs when
>> the C2 compiler thread is initializing. The compiler thread reads the
>> StubCodeDesc list while it is in an unstable state, resulting in a
>> read from an uninitialized pointer field and it then segfaults,
>> causing the VM to abort.
>> OK for 11 and 12?
> Looks good for 12.
> Looks simple enough for 11.
> Star formatting is a bit awkward:
> 37 StubCodeDesc *volatile StubCodeDesc::_list = NULL;
> 42 static StubCodeDesc *volatile _list; // the list of all descriptors
> ...should probably be:
> 37 StubCodeDesc* volatile StubCodeDesc::_list = NULL;
> 42 static StubCodeDesc* volatile _list; // the list of all descriptors
That's incorrect. Indirection binds to the right.
You need to get it right for:
int *a, b;
which would be highly misleading as
int *a, b;
But anyway, I have withdrawn the bug report: it's been fixed a
different way in current sources.
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
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