[kbuild-all] Re: [vfs:uaccess.net 16/19] net/atm/ioctl.c:180:29: sparse: sparse: Using plain integer as NULL pointer

On Fri, May 22, 2020 at 09:58:00PM +0800, kbuild test robot wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git uaccess.net > head: 0edecc020b33f8e31d8baa80735b45e8e8434700 > commit: a3929484af75ee524419edbbc4e9ce012c3d67c9 [16/19] atm: move copyin from atm_getnames() into the caller > config: arm64-randconfig-s002-20200521 (attached as .config) > compiler: aarch64-linux-gcc (GCC) 9.3.0 > reproduce: > # apt-get install sparse > # sparse version: v0.6.1-193-gb8fad4bc-dirty > git checkout a3929484af75ee524419edbbc4e9ce012c3d67c9 > # save the attached .config to linux build tree > make W=1 C=1 ARCH=arm64 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' > > If you fix the issue, kindly add following tag as appropriate > Reported-by: kbuild test robot <lkp(a)intel.com&gt; > > > sparse warnings: (new ones prefixed by >>) > > >> net/atm/ioctl.c:180:29: sparse: sparse: Using plain integer as NULL pointer Huh? > > 180 if (get_user(buf, &iobuf->buffer)) _what_ use of plain integer as a NULL pointer? <looks> Misannotated get_user() on arm64 - should be diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 32fc8061aa76..bc5c7b091152 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -304,7 +304,7 @@ do { \ __p = uaccess_mask_ptr(__p); \ __raw_get_user((x), __p, (err)); \ } else { \ - (x) = 0; (err) = -EFAULT; \ + (x) = (__force __typeof__(x))0; (err) = -EFAULT; \ } \ } while (0) and that's a _lot_ of noise in sparse logs on arm64, obviously - one for each get_user() of a pointer...