Re: [PATCH] bcachefs: Fix format specifier in validate_bset_keys()

[Geert Uytterhoeven]

Hi Kent,

On Wed, Apr 17, 2024 at 12:09 AM Kent Overstreet
<kent.overstreet@xxxxxxxxx> wrote:
> On Tue, Apr 16, 2024 at 08:16:02AM -0700, Nathan Chancellor wrote:
> > When building for 32-bit platforms, for which size_t is 'unsigned int',
> > there is a warning from a format string in validate_bset_keys():
> >
> >   fs/bcachefs/btree_io.c: In function 'validate_bset_keys':
> >   fs/bcachefs/btree_io.c:891:34: error: format '%lu' expects argument of type 'long unsigned int', but argument 12 has type 'unsigned int' [-Werror=format=]
> >     891 |                                  "bad k->u64s %u (min %u max %lu)", k->u64s,
> >         |                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >   fs/bcachefs/btree_io.c:603:32: note: in definition of macro 'btree_err'
> >     603 |                                msg, ##__VA_ARGS__);                     \
> >         |                                ^~~
> >   fs/bcachefs/btree_io.c:887:21: note: in expansion of macro 'btree_err_on'
> >     887 |                 if (btree_err_on(!bkeyp_u64s_valid(&b->format, k),
> >         |                     ^~~~~~~~~~~~
> >   fs/bcachefs/btree_io.c:891:64: note: format string is defined here
> >     891 |                                  "bad k->u64s %u (min %u max %lu)", k->u64s,
> >         |                                                              ~~^
> >         |                                                                |
> >         |                                                                long unsigned int
> >         |                                                              %u
> >   cc1: all warnings being treated as errors
> >
> > BKEY_U64s is size_t so the entire expression is promoted to size_t. Use
> > the '%zu' specifier so that there is no warning regardless of the width
> > of size_t.
> >
> > Fixes: 031ad9e7dbd1 ("bcachefs: Check for packed bkeys that are too big")
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > Closes: https://lore.kernel.org/oe-kbuild-all/202404130747.wH6Dd23p-lkp@xxxxxxxxx/
> > Closes: https://lore.kernel.org/oe-kbuild-all/202404131536.HdAMBOVc-lkp@xxxxxxxxx/
> > Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
>
> Thanks, applied

This is still not fixed in today's linux-next, while the issue is now
causing breakage on several 32-bit defconfs in v6.9-rc5.

Gr{oetje,eeting}s,

                        Geert


--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68korg

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