HSX-25: code review (round 0) for VMError::report_and_die () dies on bad PC (8015884)

[Daniel D. Daugherty]

Zhengyu,

Thanks for the review!

I will have a "round 1" code review out sometime later today.


On 7/2/13 7:50 PM, Zhengyu Gu wrote:
> Dan,
>
> Thank you for cleaning up dll_address_to_function_name(). In general, 
> it looks good to me.

Thanks!


> One possible enhancement, you can decide if should be done under this 
> bug.
>
> os_windows.cpp
>   os::address_is_in_vm(address addr)
>
> I think there is simpler way using Windows API "GetModuleHandleEx() 
> with GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS.

My Windows changes in this bug are very minimal and I think I'd
like to keep it that way. However, I will file an RFE for the
suggestion. Would this improvement count as a "starter" bug?

Dan


>
> Thanks,
>
> -Zhengyu
>
>
>
>
> On 6/21/2013 6:44 PM, Daniel D. Daugherty wrote:
>> Greetings,
>>
>> I have have a proposed fix for the following bug:
>>
>>     8015884 runThese crashed with SIGSEGV, hs_err has an error instead
>>             of stacktrace
>>     http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8015884
>>     https://jbs.oracle.com/bugs/browse/JDK-8015884
>>
>> Here are the HSX-25 webrev URLs:
>>
>> OpenJDK: http://cr.openjdk.java.net/~dcubed/8015884-webrev/0-hsx25/
>> Internal: http://javaweb.us.oracle.com/~ddaugher/8015884-webrev/0-hsx25/
>>
>> Testing:
>> -  test/runtime/6888954/vmerrors.sh has been updated to include a
>>    test for a bad function pointer
>> - vmerrors.sh has been used on MacOS X and Solaris X86 to verify
>>   that bad function pointers get better trouble shooting info
>> - (running, @ 24 hours and not yet done) JPRT build and test job
>> - (TBD) JPRT build and new test only job
>> - (TBD) Aurora Adhoc vm.quick batch for all platforms in the following
>>   configs: {Client VM, Server VM} x {fastdebug} x {-Xmixed}
>>
>> Just to be clear: This fix solves the problem of not getting a
>> stacktrace when we get a bad PC; it does not solve the underlying
>> reason why libpthread sent the VM into the weeds.
>>
>> Gory details are below. As always, comments, questions and
>> suggestions are welome.
>>
>> Dan
>>
>>
>> Gory Details:
>>
>> The primary bug fixes are:
>>
>> - the Dl_info struct should only be used if dladdr() has
>>   returned non-zero (no errors) and always check the dladdr()
>>   return value
>> - the Dl_info.dli_sname and Dl_info.dli_saddr fields should
>>   only be used if non-NULL
>> - the first two fixes are based on the Solaris dladdr() man page
>> - make logic consistent between MacOS X, Linux and Solaris:
>>   - offset is only set when a matching symbol is found (and
>>     the pointer is non-NULL)
>>
>> Cleanup bug fixes are:
>>
>> - add assert()'s to verify os::dll_address_to_function_name() and
>>   os::dll_address_to_library_name() contract for 'buf' parameter
>>
>> - HotSpot style: explicitly check int function return values
>>   rather that assume conversion to boolean, e.g.
>>
>>     if (dladdr(...)) {  =>  if (dladdr(...) != 0) {
>>
>> - consistently compare Dl_info fields against NULL instead of a mix of
>>   '0', NULL and implied boolean
>>
>> - the Dl_info.dli_fname and Dl_info.dli_fbase fields are only used if
>>   non-NULL; this was done for consistency (and paranoia); the Solaris
>>   man page does not state whether or not NULL is a permitted value for
>>   these fields
>>
>> Test changes:
>> - add case "13" for bad function pointers
>> - change VM-side of the test code so that case "12", the
>>   os::signal_raise(SIGSEGV) case, does not have to be last;
>>   this puts a ShouldNotReachHere() call after the test_num
>>   case statement so this test function will always crash
>>   the VM in non-product bits
>> - change VM-side of the test code to issue an ERROR message
>>   when an unexpected test_num value is passed
>>
>