Re: [PATCH v3] zram: don't free statically defined names

Sergey Senozhatsky
2024-09-24T05:41:56Z

On (24/09/24 07:21), Christophe JAILLET wrote:
> > > Hi,
> > >
> > > maybe kfree_const() to be more future proof and less verbose?
> >
> > kfree_const() will not work if zram is built as a module. It works
> > only for .rodata for kernel image. [1]
> >
> > 1. https://elixir.bootlin.com/linux/v6.11/source/include/asm-generic/sections.h#L177
> >
>
> If so, then it is likely that it is not correctly used elsewhere.

Oh, apparently there are drivers that use it...

So I suspect it works when you do

kstrdup_const()
kfree_const()

// I only looked at drivers/firmware/arm_scmi/bus.c

kstrdup_const() can't tell module's .rodata so it does plain
kstrdup() and then kfree_const() (for the same reason) does
plain kfree().

But calling kfree_const() on something that has not been
kstrdup_const() is unlikely to work as intended for modules.

So I guess kfree_const() works only when paired with kstrdup_const().