Re: [PATCH v2 1/2] Provide READ_ONCE_NOCHECK()

From: Ingo Molnar
Date: Wed Oct 14 2015 - 09:41:16 EST



* Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> wrote:

>
>
> On 10/13/2015 07:02 PM, kbuild test robot wrote:
> > Hi Andrey,
> >
> > [auto build test WARNING on tip/auto-latest -- if it's inappropriate base, please suggest rules for selecting the more suitable base]
> >
> > url: https://github.com/0day-ci/linux/commits/Andrey-Ryabinin/Provide-READ_ONCE_NOCHECK/20151013-204127
> > config: mn10300-allyesconfig (attached as .config)
> > reproduce:
> > wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
> > chmod +x ~/bin/make.cross
> > # save the attached .config to linux build tree
> > make.cross ARCH=mn10300
> >
> > All warnings (new ones prefixed by >>):
> >
> > fs/nfs/filelayout/filelayout.c: In function 'filelayout_read_pagelist':
> > fs/nfs/filelayout/filelayout.c:476:2: warning: format '%Zu' expects argument of type 'size_t', but argument 5 has type '__u32' [-Wformat=]
> > dprintk("--> %s ino %lu pgbase %u req %Zu@%llu\n",
> > ^
>
> So the actual warning is here. And it's not new.
>
> > In file included from include/linux/nfs_fs.h:28:0,
> > from fs/nfs/filelayout/filelayout.c:32:
> > fs/nfs/filelayout/filelayout.c: In function 'filelayout_write_pagelist':
> > include/linux/compiler.h:270:8: warning: format '%Zu' expects argument of type 'size_t', but argument 5 has type '__u32' [-Wformat=]
> > union { typeof(x) __val; char __c[1]; } __u; \
> > ^
> > include/linux/sunrpc/debug.h:33:24: note: in definition of macro 'dfprintk'
> > printk(KERN_DEFAULT args); \
> > ^
> >>> include/linux/compiler.h:274:22: note: in expansion of macro '__READ_ONCE'
> > #define READ_ONCE(x) __READ_ONCE(x, _check)
> > ^
>
> And this 'note: in expansion of macro' belongs to the warning above.
> So it's a false-positive.

So if this is a new warning introduced by these patches then the warning needs to
be addresses - regardless of whether it's a false positive or not.

Thanks,

Ingo
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