Re: [PATCH v2] Bluetooth: MGMT: Fix uses of bitmap_from_u64

[Luiz Augusto von Dentz <luiz.dentz@gmail.com>]

Hi Marcel,

On Thu, May 19, 2022 at 11:09 AM Marcel Holtmann <marcel@holtmann.org> wrote:
>
> Hi Luiz,
>
> > bitmap_from_u64 expects at least 8 bytes to be declared since it doesn't
> > take any parameter regarding the number of bits causing the following
> > warnings:
> >
> > In file included from include/linux/cpumask.h:12,
> >                 from include/linux/mm_types_task.h:14,
> >                 from include/linux/mm_types.h:5,
> >                 from include/linux/buildid.h:5,
> >                 from include/linux/module.h:14,
> >                 from net/bluetooth/mgmt.c:27:
> > In function 'bitmap_copy',
> >    inlined from 'bitmap_copy_clear_tail' at include/linux/bitmap.h:270:2,
> >    inlined from 'bitmap_from_u64' at include/linux/bitmap.h:622:2,
> >    inlined from 'set_device_flags' at net/bluetooth/mgmt.c:4534:4:
> > include/linux/bitmap.h:261:9: warning: 'memcpy' forming offset [4, 7] is
> > out of the bounds [0, 4] of object 'flags' with type
> > 'long unsigned int[1]' [-Warray-bounds]
> >  261 |         memcpy(dst, src, len);
> >      |         ^~~~~~~~~~~~~~~~~~~~~
> > In file included from include/linux/kasan-checks.h:5,
> >                 from include/asm-generic/rwonce.h:26,
> >                 from ./arch/arm/include/generated/asm/rwonce.h:1,
> >                 from include/linux/compiler.h:248,
> >                 from include/linux/build_bug.h:5,
> >                 from include/linux/container_of.h:5,
> >                 from include/linux/list.h:5,
> >                 from include/linux/module.h:12,
> >                 from net/bluetooth/mgmt.c:27:
> > net/bluetooth/mgmt.c: In function 'set_device_flags':
> > net/bluetooth/mgmt.c:4532:40: note: 'flags' declared here
> > 4532 |                         DECLARE_BITMAP(flags, __HCI_CONN_NUM_FLAGS);
> >      |                                        ^~~~~
> > include/linux/types.h:11:23: note: in definition of macro 'DECLARE_BITMAP'
> >   11 |         unsigned long name[BITS_TO_LONGS(bits)]
> >      |                       ^~~~
> >
> > In order to fix the above this initializes a variable using
> > DECLARE_BITMAP with the current_flags and then uses bitmap_subset to
> > check if the flags being set are a subset of hdev->conn_flags that way
> > all the checks are performed using bitmap APIs and conversion to u32
> > only happen when really needed.
> >
> > Fixes: a9a347655d22 ("Bluetooth: MGMT: Add conditions for setting HCI_CONN_FLAG_REMOTE_WAKEUP")
> > Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> > Suggested-by: Yury Norov <yury.norov@gmail.com>
> > Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
> > ---
> > net/bluetooth/mgmt.c | 43 ++++++++++++++++++-------------------------
> > 1 file changed, 18 insertions(+), 25 deletions(-)
>
> what is up with the kbot issues?

Will fix that.

> Regards
>
> Marcel
>


-- 
Luiz Augusto von Dentz