Re: Build regressions/improvements in v5.18-rc1

[Geert Uytterhoeven]

Hi Dave

CC Arnd

On Mon, Apr 4, 2022 at 11:27 AM Dave Chinner <david@xxxxxxxxxxxxx> wrote:
> On Mon, Apr 04, 2022 at 10:16:08AM +0200, Geert Uytterhoeven wrote:
> > On Mon, 4 Apr 2022, Geert Uytterhoeven wrote:
> > > Below is the list of build error/warning regressions/improvements in
> > > v5.18-rc1[1] compared to v5.17[2].
> > >
> > > Summarized:
> > >  - build errors: +36/-15
> > >  - build warnings: +5/-38
> > >
> > > Happy fixing! ;-)
>
> Well....
>
> > >  + /kisskb/src/fs/xfs/xfs_buf.h: error: initializer element is not constant:  => 46:23
>
> Looking at:
>
> http://kisskb.ellerman.id.au/kisskb/buildresult/14714961/
>
> The build error is:
>
> /kisskb/src/fs/xfs/./xfs_trace.h:432:2: note: in expansion of macro 'TP_printk'
>   TP_printk("dev %d:%d daddr 0x%llx bbcount 0x%x hold %d pincount %d "
>   ^
> /kisskb/src/fs/xfs/./xfs_trace.h:440:5: note: in expansion of macro '__print_flags'
>      __print_flags(__entry->flags, "|", XFS_BUF_FLAGS),
>      ^
> /kisskb/src/fs/xfs/xfs_buf.h:67:4: note: in expansion of macro 'XBF_UNMAPPED'
>   { XBF_UNMAPPED,  "UNMAPPED" }
>     ^
> /kisskb/src/fs/xfs/./xfs_trace.h:440:40: note: in expansion of macro 'XFS_BUF_FLAGS'
>      __print_flags(__entry->flags, "|", XFS_BUF_FLAGS),
>                                         ^
> /kisskb/src/fs/xfs/./xfs_trace.h: In function 'trace_raw_output_xfs_buf_flags_class':
> /kisskb/src/fs/xfs/xfs_buf.h:46:23: error: initializer element is not constant
>  #define XBF_UNMAPPED  (1 << 31)/* do not map the buffer */
>
> This doesn't make a whole lotta sense to me. It's blown up in a
> tracepoint macro in XFS that was not changed at all in 5.18-rc1, nor
> was any of the surrounding XFS code or contexts.  Perhaps something
> outside XFS changed to cause this on these platforms?

Upon closer look, all builds showing this issue are using gcc-5...

> Can you bisect this, please?

Fortunately I still have gcc-5 installed on an older machine,
and I could reproduce the issue on amd64 with
"make allmodconfig fs/xfs/xfs_trace.o".

Bisection points to commit e8c07082a810fbb9 ("Kbuild: move to
-std=gnu11").

[1] gcc version 5.5.0 20171010 (Ubuntu 5.5.0-12ubuntu1

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds