[Libguestfs] libnbd golang failure on RISC-V

[Nir Soffer]

On Thu, Jun 9, 2022 at 6:24 PM Richard W.M. Jones <rjones at redhat.com> wrote:
>
> On Thu, Jun 09, 2022 at 03:20:02PM +0100, Daniel P. Berrangé wrote:
> > > + go test -count=1 -v
> > > === RUN   Test010Load
> > > --- PASS: Test010Load (0.00s)
> > > === RUN   TestAioBuffer
> > > --- PASS: TestAioBuffer (0.00s)
> > > === RUN   TestAioBufferFree
> > > --- PASS: TestAioBufferFree (0.00s)
> > > === RUN   TestAioBufferBytesAfterFree
> > > SIGABRT: abort
> > > PC=0x3fdf6f9bac m=0 sigcode=18446744073709551610
> >
> > So suggesting TestAioBufferBytesAfterFree is as fault, but quite
> > odd as that test case is trivial and whle it allocates some
> > native memory it doesn't seem to write to it. Unless the problem
> > happened in an earlier test case and we have delayed detection ?
> >
> > I guess I'd try throwing darts at the wall by chopping out bits
> > of test code to see what makes it disappear.
> >
> > Perhaps also try swapping MakeAioBuffer with MakeAioBufferZero
> > in case pre-existing data into the C.malloc()d block is confusing
> > Go ?
>
> Interestingly if I remove libnbd_020_aio_buffer_test.go completely,
> and disable GODEBUG, then the tests pass.  (Reproducer commands at end
> of email).  So I guess at least one of the problems is confined to
> this test and/or functions it calls in the main library.
> Unfortunately this test is huge.
>
> At your suggestion, replacing every MakeAioBuffer with
> MakeAioBufferZero in that test, but it didn't help.  Also tried
> replacing malloc -> calloc in the aio_buffer.go implementation which
> didn't help.
>
> I'll try some more random things ...
>
> Rich.
>
>
> $ emacs -nw run.in    # comment out GODEBUG line
> $ emacs -nw golang/Makefile.am   # remove libnbd_020_aio_buffer_test.go line
> $ mv golang/libnbd_020_aio_buffer_test.go golang/libnbd_020_aio_buffer_test.nogo
> $ make run
> $ make
> $ make -C golang check
> ...
> PASS: run-tests.sh

So when skipping libnbd_020_aio_buffer_test.go we don't get the warning about
Go pointer in C memory?

If true, can you find the test triggering this issue?

You can run only some tests using -run={regex}, for example:

$ go test -v -run=TestAioBuffer.+AfterFree
=== RUN   TestAioBufferBytesAfterFree
--- PASS: TestAioBufferBytesAfterFree (0.00s)
=== RUN   TestAioBufferSliceAfterFree
--- PASS: TestAioBufferSliceAfterFree (0.00s)
=== RUN   TestAioBufferGetAfterFree
--- PASS: TestAioBufferGetAfterFree (0.00s)
PASS