RFR 8159284: bigapps/Jetty - assert(jfa->last_Java_sp() > sp()) failed with tracing code in use

[dean.long at oracle.com]

Upon a closer look, it appears that the backtraces we get for a crash 
come from print_native_stack() in debug.cpp, and that code uses a 
slightly different algorithm, so your changes shouldn't affect it.

dl


On 8/1/16 6:11 PM, dean.long at oracle.com wrote:
> Hi Coleen.  If I understand correctly, previously we would get 
> backtraces that end with the first C frame:
>
> [...]
> J 3335 C1 java.lang.Thread.run()V java.base at 9-ea (17 bytes) @ 
> 0xe7fdc480 [0xe7fdc420+0x00000060]
> v  ~StubRoutines::call_stub
> V  [libjvm.so+0x66fe39]  JavaCalls::call_helper(JavaValue*, 
> methodHandle const&, JavaCallArguments*, Thread*)+0x2b9
> V  [libjvm.so+0x931669]  os::os_exception_wrapper(void (*)(JavaValue*, 
> methodHandle const&, JavaCallArguments*, Thread*), JavaValue*, 
> methodHandle const&, JavaCallArguments*, Thread*)+0x19
> V  [libjvm.so+0x66eb2b]  JavaCalls::call_virtual(JavaValue*, Handle, 
> KlassHandle, Symbol*, Symbol*, Thread*)+0x13b
> V  [libjvm.so+0x708069]  thread_entry(JavaThread*, Thread*)+0x89
> V  [libjvm.so+0xaa5434]  JavaThread::thread_main_inner()+0xf4
> V  [libjvm.so+0xaa5589]  JavaThread::run()+0x119
> V  [libjvm.so+0x933cdc]  thread_native_entry(Thread*)+0x10c
> C  [libpthread.so.0+0x6bc9]
> C  [libc.so.6+0xe2c9e]  clone+0x5e
>
>
> but now with your change, won't all backtraces end on the last Java 
> frame?  So the above backtrace would be truncated to:
>
> [...]
> J 3335 C1 java.lang.Thread.run()V java.base at 9-ea (17 bytes) @ 
> 0xe7fdc480 [0xe7fdc420+0x00000060]
>
>
> dl
>
> On 8/1/16 4:38 PM, Coleen Phillimore wrote:
>> Summary: Test condition in assert in frame::safe_for_sender() for 
>> entry frames and return false.
>>
>> This bug is for a confidential part of the project that needs more 
>> robustness checks to verify that frame::sender() can be called.
>>
>> Also refactored into frame::entry_frame_is_safe() because these 
>> platforms had the same code for entry frames to determine whether it 
>> is still safe to trust this frame to call sender(). These platforms 
>> had also the same assert in sender_for_entry_frame() that the 
>> sampling code hit.
>>
>> Tested with our nightly tests on all platforms and bigapps/Jetty.
>>
>> open webrev at http://cr.openjdk.java.net/~coleenp/8159284.01/webrev
>>
>> Thanks,
>> Coleen
>>
>