Re: [LKP] [xarray] 0e9446c35a: WARNING:at_include/linux/xarray.h:#xa_mk_value

[Matthew Wilcox]

On Mon, Nov 05, 2018 at 09:57:47AM -0800, Linus Torvalds wrote:
> Willy,
> 
> On Sun, Nov 4, 2018 at 11:03 PM kernel test robot <rong.a.chen@xxxxxxxxx> wrote:
> >
> > commit: 0e9446c35a80931044b6d8d2d74a9cabd248539f ("xarray: Add range store functionality")
> ...
> > [   11.880031] WARNING: CPU: 0 PID: 1 at include/linux/xarray.h:54 xa_mk_value+0x7/0x10
> > [   11.881944] EIP: xa_mk_value+0x7/0x10
> > [   11.883565] Call Trace:
> > [   11.883565]  __check_store_range+0xe/0x171
> > [   11.883565]  check_store_range+0x5d/0x87
> 
> If I read this right, it's simply this case:
> 
>                 __check_store_range(xa, UINT_MAX + i, UINT_MAX + j);
> 
> which turns into negative values on a 32-bit machine, and then
> xa_mk_value() warns.
> 
> Should that part of the test be surrounded by #ifdef CONFIG_64BIT? Or
> did you _want_ the warnings?

I should have just made that (1 << 24) instead of UINT_MAX.  I had forgotten
about 32-bit machines while writing that test.

That prompted me to actually build the test suite on 32-bit and there's
a few other things in there that want fixing.  I'll have a pull request
for you later today.