lkml.org 
[lkml]   [2021]   [Mar]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 3/3] static_call: Fix static_call_update() sanity check
On Thu, Mar 18, 2021 at 05:58:38PM +0100, Peter Zijlstra wrote:

> > For CONFIG_MODULE_UNLOAD, the code ends up in the normal text area, so
> > static_call_is_init() is false and kernel_text_address() is true.
> >
> > For !CONFIG_MODULE_UNLOAD, the code gets discarded during module load,
> > so static_call_is_init() and kernel_text_address() are both false. I
> > guess that will trigger a warning?
>
> Oh gawd, more variants.
>
> Afaict MODULE_UNLOAD, by virtue of that #ifdef in

!MODULE_UNLOAD (obv)

> rewrite_section_headers() won't even load the .exit sections. Afaict
> that will break: alterative, jump_label and static_call patching all in
> one go.

Jessica, can you explain how !MODULE_UNLOAD is supposed to work?
Alternatives, jump_labels and static_call all can have relocations into
__exit code. Not loading it at all would be BAD.

For alternatives all we really need it to discard it after init, for
jump_label and static_call we additinoally need to the code to identify
as init (ie, within_module_init() must return true for it).

\
 
 \ /
  Last update: 2021-03-19 13:59    [W:0.109 / U:0.932 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site