RFR(S): 8205946: JVM crash after call to ClassLoader::setup_bootstrap_search_path()

[Calvin Cheung]

Hi Lois,

Thanks for your review.

On 7/9/18, 11:58 AM, Lois Foltan wrote:
> On 7/9/2018 1:29 PM, Calvin Cheung wrote:
>
>> bug: https://bugs.openjdk.java.net/browse/JDK-8205946
>>
>> webrev: http://cr.openjdk.java.net/~ccheung/8205946/webrev.00/
>>
>> The JVM crash could be simulated by renaming/removing the modules 
>> file under the jdk/lib directory.
>> The proposed simple fix is to perform a vm_exit_during_initialization().
>
> Hi Calvin,
>
> Some clarifying questions.  Is this just an issue for exploded builds?
I don't think so. As mentioned above, I could reproduce the crash with a 
regular jdk image build by renaming the modules file under the jdk/lib 
directory.
>   I would prefer the exit to occur if the os::stat() fails for the 
> system class path in os::set_boot_path().
Instead of exiting in os::set_boot_path(), how about checking the return 
status of os::set_boot_path() in the caller and exiting there like the 
following:
bash-4.2$ hg diff os_linux.cpp
diff --git a/src/hotspot/os/linux/os_linux.cpp 
b/src/hotspot/os/linux/os_linux.cpp
--- a/src/hotspot/os/linux/os_linux.cpp
+++ b/src/hotspot/os/linux/os_linux.cpp
@@ -367,7 +367,9 @@
        }
      }
      Arguments::set_java_home(buf);
-    set_boot_path('/', ':');
+    if (!set_boot_path('/', ':')) {
+      vm_exit_during_initialization("Failed setting boot class path.", 
NULL);
+    }
    }

Note that before the above change, the return status of set_boot_path() 
isn't checked.
The above would involve changing 5 of those os_*.cpp files, one for each 
O/S.

>   With certainly an added assert later in 
> ClassLoader::setup_bootstrap_search_path() to ensure that the system 
> class path is never NULL.
Sure, I can add an assert there.
I'll post updated webrev once I've made the change and done testing.

thanks,
Calvin
>
> Thanks,
> Lois
>
>>
>> Ran hs-tier{1,2,3} tests successfully including the new test case.
>>
>> thanks,
>> Calvin
>