Re: [Qemu-devel] [PATCH v5 23/24] replay: add BH oneshot event for block layer

["Pavel Dovgalyuk" <dovgaluk@ispras.ru>]

> -----Original Message-----
> From: Alex Bennée [mailto:alex.bennee@linaro.org]
> Sent: Friday, July 27, 2018 7:45 PM
> To: Pavel Dovgalyuk
> Cc: 'Pavel Dovgalyuk'; qemu-devel@nongnu.org; kwolf@redhat.com; peter.maydell@linaro.org;
> war2jordan@live.com; crosthwaite.peter@gmail.com; boost.lists@gmail.com; quintela@redhat.com;
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> armbru@redhat.com; maria.klimushenkova@ispras.ru; kraxel@redhat.com;
> thomas.dullien@googlemail.com; pbonzini@redhat.com; mreitz@redhat.com; dgilbert@redhat.com;
> rth@twiddle.net
> Subject: Re: [PATCH v5 23/24] replay: add BH oneshot event for block layer
> 
> 
> Pavel Dovgalyuk <dovgaluk@ispras.ru> writes:
> 
> >> From: Alex Bennée [mailto:alex.bennee@linaro.org]
> >> > Replay is capable of recording normal BH events, but sometimes
> >> > there are single use callbacks scheduled with aio_bh_schedule_oneshot
> >> > function. This patch enables recording and replaying such callbacks.
> >> > Block layer uses these events for calling the completion function.
> >> > Replaying these calls makes the execution deterministic.
> >> >
> >> > Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
> >>
> >> I'm not sure what about this commit causes the compile breakage I'm
> >> seeing:
> >>
> >>   LINK    aarch64-linux-user/qemu-aarch64
> >> ../libqemuutil.a(cpu-get-icount.o):(.bss+0x0): multiple definition of `use_icount'
> >> exec.o:(.bss+0x58): first defined here
> >> collect2: error: ld returned 1 exit status
> >> Makefile:199: recipe for target 'qemu-aarch64' failed
> >> make[1]: *** [qemu-aarch64] Error 1
> >> Makefile:481: recipe for target 'subdir-aarch64-linux-user' failed
> >> make: *** [subdir-aarch64-linux-user] Error 2
> >>
> >> It only occurs on a make clean && make -j on that commit though. It's
> >> hidden if you do incremental builds.
> >
> > make distclean works for me in such cases.
> 
> Hmmm
> 
> make distclean
> ./configure
> make
> 
> And I get:
> 
> LINK    aarch64-linux-user/qemu-aarch64
> ../libqemuutil.a(cpu-get-icount.o):(.bss+0x0): multiple definition of `use_icount'
> exec.o:(.bss+0x58): first defined here
> collect2: error: ld returned 1 exit status
> Makefile:199: recipe for target 'qemu-aarch64' failed
> make[1]: *** [qemu-aarch64] Error 1
> Makefile:481: recipe for target 'subdir-aarch64-linux-user' failed
> make: *** [subdir-aarch64-linux-user] Error 2

That's strange. As I understand, linux-user emulators does not include block layer.
They also don't include record/replay.
Why then block- and record-related stub affects the build?

Pavel Dovgalyuk