RFR: 8360941: [ubsan] MemRegion::end() shows runtime error: applying non-zero offset 8388608 to null pointer [v3]

[Matthias Baesken]

On Wed, 16 Jul 2025 14:45:05 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

>> When running HS test
>> gtest/GTestWrapper.java
>> with ubsan-enabled binaries on macOS aarch64, the following error is reported (did not see this so far on Linux but there we use gcc and it seems the gcc/ubsan checks are a bit more limited).
>> 
>> test/hotspot/gtest/gc/g1/test_freeRegionList.cpp:37: Failure
>> Death test: child_G1FreeRegionList_length_()
>>     Result: died but not with expected exit code:
>>             Terminated by signal 6 (core dumped)
>> Actual msg:
>> 
>> [  DEATH   ] /jdk/src/hotspot/share/memory/memRegion.hpp:66:43: runtime error: applying non-zero offset 8388608 to null pointer
>> [  DEATH   ]     #0 0x108afd6f4 in MemRegion::end() const+0x84 (libjvm.dylib:arm64+0x16556f4)
>> [  DEATH   ]     #1 0x1075c68a0 in G1FreeRegionList_length_other_vm_Test::TestBody()+0x380 (libjvm.dylib:arm64+0x11e8a0)
>> [  DEATH   ]     #2 0x1090f3bb0 in testing::Test::Run()+0xc0 (libjvm.dylib:arm64+0x1c4bbb0)
>> [  DEATH   ]     #3 0x1090f4d94 in testing::TestInfo::Run()+0x1e4 (libjvm.dylib:arm64+0x1c4cd94)
>> [  DEATH   ]     #4 0x1090f6754 in testing::TestSuite::Run()+0x43c (libjvm.dylib:arm64+0x1c4e754)
>> [  DEATH   ]     #5 0x109103ca0 in testing::internal::UnitTestImpl::RunAllTests()+0x48c (libjvm.dylib:arm64+0x1c5bca0)
>> [  DEATH   ]     #6 0x109103588 in testing::UnitTest::Run()+0x78 (libjvm.dylib:arm64+0x1c5b588)
>> [  DEATH   ]     #7 0x1074a9ac0 in runUnitTestsInner(int, char**)+0x724 (libjvm.dylib:arm64+0x1ac0)
>> [  DEATH   ]     #8 0x102dc3f18 in main+0x2c (gtestLauncher:arm64+0x100003f18)
>> [  DEATH   ]     #9 0x196fea0dc  (<unknown module>)
>> [  DEATH   ] 
>> [  DEATH   ] SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /jdk/src/hotspot/share/memory/memRegion.hpp:66:43 in 
>> [  DEATH   ] 
>> 
>> 
>> 
>> Seems the test_freeRegionList.cpp uses a special MemRegion starting at nullptr ; but this causes a bit of trouble when adding to start == nullptr .
>> So far I see this issue just in the gtest, seems other MemRegion objects do not start at nullptr .
>
> Matthias Baesken has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - blank
>  - blank

Taking 'some other address' than nullptr / 0  as suggested  just fails  (I worked yesterday with opt build where no failure was seen).
But fastdebug leads to this assert  , any ideas  ?
Or suggestions for a 'better' address  (!= 0) that works ?


#  Internal Error (/openjdk-jdk-dev-linux_aarch64-dbg/jdk/src/hotspot/share/gc/g1/g1HeapRegion.cpp:254), pid=1541642, tid=1541642
#  assert(Universe::on_page_boundary(mr.start()) && Universe::on_page_boundary(mr.end())) failed: invalid space boundaries
#
# Problematic frame:
# V  [libjvm.so+0x110d75c]  G1HeapRegion::G1HeapRegion(unsigned int, G1BlockOffsetTable*, MemRegion, G1CardSetConfiguration*)+0x158
#

---------------  T H R E A D  ---------------

Current thread (0x0000c8cccb63ed40):  JavaThread "main"             [_thread_in_native, id=1541642, stack(0x0000ffffeb8e0000,0x0000ffffebade000) (2040K)]

Stack: [0x0000ffffeb8e0000,0x0000ffffebade000],  sp=0x0000ffffebadc6c0,  free space=2033k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V  [libjvm.so+0x110d75c]  G1HeapRegion::G1HeapRegion(unsigned int, G1BlockOffsetTable*, MemRegion, G1CardSetConfiguration*)+0x158  (g1HeapRegion.cpp:254)
V  [libjvm.so+0x5a235c]  test_G1FreeRegionList_length_()+0x20c  (test_freeRegionList.cpp:75)
V  [libjvm.so+0x5a29cc]  G1FreeRegionList_length_other_vm_Test::TestBody()+0x32c  (test_freeRegionList.cpp:37)
V  [libjvm.so+0x2075298]  testing::Test::Run()+0xe4  (gtest.cc:2670)
V  [libjvm.so+0x2075424]  testing::TestInfo::Run()+0x170  (gtest.cc:2836)
V  [libjvm.so+0x2075710]  testing::TestSuite::Run()+0x2d0  (gtest.cc:3015)
V  [libjvm.so+0x2081774]  testing::internal::UnitTestImpl::RunAllTests()+0x360  (gtest.cc:5920)
V  [libjvm.so+0x207506c]  testing::UnitTest::Run()+0x7c  (gtest.cc:2670)
V  [libjvm.so+0x45c31c]  runUnitTestsInner(int, char**)+0x3fc  (gtest.h:2317)
C  [gtestLauncher+0x7c0]  main+0x1c  (gtestLauncher.cpp:40)
C  [libc.so.6+0x284c4]
C  [libc.so.6+0x28598]  __libc_start_main+0x98

-------------

PR Comment: https://git.openjdk.org/jdk/pull/26216#issuecomment-3082910474