linux-kernel - Re: [PATCH v7 2/4] lib/test_bitmap.c: Add for_each_set

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Date:   Fri, 5 Jun 2020 15:24:28 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Syed Nayyar Waris <syednwaris@...il.com>
Cc:     kbuild test robot <lkp@...el.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        kbuild-all@...ts.01.org,
        William Breathitt Gray <vilhelm.gray@...il.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v7 2/4] lib/test_bitmap.c: Add for_each_set_clump test
 cases

On Fri, Jun 05, 2020 at 02:12:54AM +0530, Syed Nayyar Waris wrote:
> On Sun, May 31, 2020 at 12:50 AM kbuild test robot <lkp@...el.com> wrote:

> > >> WARNING: modpost: lib/test_bitmap.o(.data+0xe80): Section mismatch in reference from the variable clump_test_data to the variable .init.rodata:clump_exp1
> > The variable clump_test_data references
> > the variable __initconst clump_exp1
> > If the reference is valid then annotate the
> > variable with or __refdata (see linux/init.h) or name the variable:
> >
> > --
> > >> WARNING: modpost: lib/test_bitmap.o(.data+0xec8): Section mismatch in reference from the variable clump_test_data to the variable .init.rodata:clump_exp2
> > The variable clump_test_data references
> > the variable __initconst clump_exp2
> > If the reference is valid then annotate the
> > variable with or __refdata (see linux/init.h) or name the variable:
> >
> > --
> > >> WARNING: modpost: lib/test_bitmap.o(.data+0xf10): Section mismatch in reference from the variable clump_test_data to the variable .init.rodata:clump_exp3
> > The variable clump_test_data references
> > the variable __initconst clump_exp3
> > If the reference is valid then annotate the
> > variable with or __refdata (see linux/init.h) or name the variable:
> >
> > --
> > >> WARNING: modpost: lib/test_bitmap.o(.data+0xf58): Section mismatch in reference from the variable clump_test_data to the variable .init.rodata:clump_exp4
> > The variable clump_test_data references
> > the variable __initconst clump_exp4
> > If the reference is valid then annotate the
> > variable with or __refdata (see linux/init.h) or name the variable:

> I am unable to reproduce the compilation warning.

You have to enable section mismatch checker.

> I ran the command:
> make W=1 C=1 ARCH=x86_64 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__'  lib/
> 
> But the compilation warning didn't show up. Can anyone please point to me
> what I am doing wrong here? How shall I reproduce the warning? Thanks !

You put some data into init section of the object, while you are trying to
access it from non-init one. It's easy-to-fix issue.

-- 
With Best Regards,
Andy Shevchenko