RFR: 8333354: ubsan: frame.inline.hpp:91:25: and src/hotspot/share/runtime/frame.inline.hpp:88:29: runtime error: member call on null pointer of type 'const struct SmallRegisterMap' [v4]

[Kim Barrett]

On Thu, 25 Jul 2024 13:42:48 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

>> When running with ubsan - enabled binaries, some tests trigger the following report :
>> 
>> src/hotspot/share/runtime/frame.inline.hpp:91:25: runtime error: member call on null pointer of type 'const struct SmallRegisterMap'
>>     #0 0x7fc1df86071e in unsigned char* frame::oopmapreg_to_location<SmallRegisterMap>(VMRegImpl*, SmallRegisterMap const*) const src/hotspot/share/runtime/frame.inline.hpp:91
>>     #1 0x7fc1df86071e in void OopMapDo<OopClosure, DerivedOopClosure, IncludeAllValues>::iterate_oops_do<SmallRegisterMap>(frame const*, SmallRegisterMap const*, ImmutableOopMap const*) src/hotspot/share/compiler/oopMap.inline.hpp:106
>>     #2 0x7fc1df8611df in void OopMapDo<OopClosure, DerivedOopClosure, IncludeAllValues>::oops_do<SmallRegisterMap>(frame const*, SmallRegisterMap const*, ImmutableOopMap const*) src/hotspot/share/compiler/oopMap.inline.hpp:157
>>     #3 0x7fc1df8611df in FrameOopIterator<SmallRegisterMap>::oops_do(OopClosure*) src/hotspot/share/oops/stackChunkOop.cpp:63
>>     #4 0x7fc1dcfc8745 in BarrierSetStackChunk::encode_gc_mode(stackChunkOopDesc*, OopIterator*) src/hotspot/share/gc/shared/barrierSetStackChunk.cpp:85
>>     #5 0x7fc1df854080 in bool TransformStackChunkClosure::do_frame<(ChunkFrames)0, SmallRegisterMap>(StackChunkFrameStream<(ChunkFrames)0> const&, SmallRegisterMap const*) src/hotspot/share/oops/stackChunkOop.cpp:319
>>     #6 0x7fc1df854080 in void stackChunkOopDesc::iterate_stack<(ChunkFrames)0, TransformStackChunkClosure>(TransformStackChunkClosure*) src/hotspot/share/oops/stackChunkOop.inline.hpp:233
>>     #7 0x7fc1df82f184 in void stackChunkOopDesc::iterate_stack<TransformStackChunkClosure>(TransformStackChunkClosure*) src/hotspot/share/oops/stackChunkOop.inline.hpp:199
>> 
>> Seems in case of (at least) class SmallRegisterMap we miss handling nullptr .
>
> Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:
> 
>   add patch of Kim Barrett

It's annoying that we have all these very similar platform-specific classes of
non-trivial size.  It seems like it ought to be possible to refactor to reduce the
duplication.  But it might not be worth the trouble, and certainly not as part of
this change.

The additions @MBaesken has made to my prototype look good to me.

Looks good except missing some copyright updates.

I think when incorporating something like my suggested changes, the PR author
can be considered to have reviewed them.  The goal is to have some number of
people look over the code and approve all the pieces (an author and 2 reviewers).
At least, that's my recollection of some prior discussions of situations like this.
But I agree it can feel a little incestuous having 2 authors who are playing a
reviewer roll for the other's work, and especially when there's some back and
forth on it.

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

Changes requested by kbarrett (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/20296#pullrequestreview-2205667735