RFR (S, URGENT) 8149038: SIGSEGV at frame::is_interpreted_frame_valid -> StubRoutines::SafeFetchN

[Coleen Phillimore]

On 2/4/16 6:26 PM, Daniel D. Daugherty wrote:
> On 2/4/16 4:08 PM, Markus Gronlund wrote:
>> Hi Coleen,
>>
>> Thanks for reverting, looks good.
>
> Agreed, but also agree with Markus that it would be a shame to
> lose the cleanups.
>
> Since it's an integration_blocker, I can see why you want to
> try to very reduced risk... Do you have plans to take another
> run at the cleaned up version?

No, I don't really.  It eliminates 2 lines in a function and I don't see 
how eliminating else's is cleaner or at least cleaner enough to file an RFE.

Okay, the cleaner has_method_vptr() compiles on linux.  It better 
compile on windows.

open webrev at http://cr.openjdk.java.net/~coleenp/8149038.02/

thanks,
Coleen

>
> Dan
>
>
>>
>> /Markus
>>
>> PS I don’t know if you want to go straight back to the previous 
>> version, but I still think this piece could be tightened a bit:
>>
>> bool Method::has_method_vptr(const void* ptr) {
>>    assert(ptr != NULL, "invariant");
>>
>>    // This assumes that the vtbl pointer is the first word of a C++ 
>> object.
>>    // This assumption is also in universe.cpp patch_klass_vtble
>>    const Method m;
>>    return dereference_vptr(&m) == dereference_vptr(ptr);
>> }
>>
>> // Check that this pointer is valid by checking that the vtbl pointer 
>> matches
>> bool Method::is_valid_method() const {
>>    if (this == NULL) {
>>      return false;
>>    }
>>    if ((intptr_t(this) & (wordSize - 1)) != 0) {
>>      return false;
>>    }
>>    if (!is_metaspace_object()) {
>>      return false;
>>    }
>>    return has_method_vptr(this);
>> }
>>
>>
>>
>> -----Original Message-----
>> From: Coleen Phillimore
>> Sent: den 4 februari 2016 23:44
>> To: hotspot-dev at openjdk.java.net
>> Subject: Re: RFR (S, URGENT) 8149038: SIGSEGV at 
>> frame::is_interpreted_frame_valid -> StubRoutines::SafeFetchN
>>
>>
>>
>> On 2/4/16 5:40 PM, Coleen Phillimore wrote:
>>> Summary: Backout change for 8146984 but add an alignment check which
>>> may have caught original bug.
>>>
>>> Will retest with new check once this isn't an integration blocker. Ran
>>> original tests that failed.
>>>
>>> open webrev at http://cr.openjdk.java.net/~coleenp/8149038.01/
>>> bug link https://bugs.openjdk.java.net/browse/JDK-8149038
>> The original bug is:
>>
>> https://bugs.openjdk.java.net/browse/JDK-8146984
>>
>> Coleen
>>> Thanks,
>>> Coleen
>