Subject: linux-next: build warning after merge of the bluetooth tree

From: Stephen Rothwell <[email-masked]>
Date: Mon, 16 May 2022 17:57:57 +1000

Hi all,

After merging the bluetooth tree, today's linux-next build (arm
multi_v7_defconfig) produced this warning:

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)]
      |                       ^~~~

Introduced by commit

  a9a347655d22 ("Bluetooth: MGMT: Add conditions for setting HCI_CONN_FLAG_REMOTE_WAKEUP")

Bitmaps consist of unsigned longs (in this case 32 bits) ...

(This warning only happens due to chnges in the bitmap tree.)

-- 
Cheers,
Stephen Rothwell