Re: [GIT PULL] MFD fixes for v5.2

From: Linus Torvalds
Date: Mon Jun 17 2019 - 13:38:37 EST

On Mon, Jun 17, 2019 at 3:01 AM Lee Jones <lee.jones@xxxxxxxxxx> wrote:
> Enjoy!


This is still entirely wrong.

You can't just randomly cast an "u32 *" to "unsigned long *".

It wasn't correct when you did it the other way in regmap_read(), but
it's also not correct when you now for it this way for

You can do

u32 regmap_bits;
unsigned long bits;

and then

ret = regmap_read(stmfx->map, STMFX_REG_IRQ_PENDING, &regmap_bits);
bits = regmap_bits;
for_each_set_bit(n, &bits, STMFX_REG_IRQ_SRC_MAX) ..

but casting pointers at either point is *completely* wrong.

Yes, yes, it happens to work on little-endian, but on a 64-bit
big-endian machine, the low 32 bits of the "unsigned int" will have
absolutely _zero_ overlap with the low 32 bits of the "unsigned long"
in memory.

When you moved the cast to for_each_set_bit(), it only moves the
access of the bogus bits to another place instead.

So that patch doesn't fix anything at all, it only moves the same error around.