lkml.org 
[lkml]   [2020]   [Mar]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RESEND][PATCH v3 03/17] module: Properly propagate MODULE_STATE_COMING failure
On Wed, Mar 25, 2020 at 06:35:22PM +0100, Jessica Yu wrote:
> +++ Peter Zijlstra [24/03/20 14:56 +0100]:
> > Now that notifiers got unbroken; use the proper interface to handle
> > notifier errors and propagate them.
> >
> > There were already MODULE_STATE_COMING notifiers that failed; notably:
> >
> > - jump_label_module_notifier()
> > - tracepoint_module_notify()
> > - bpf_event_notify()
> >
> > By propagating this error, we fix those users.
> >
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> > Cc: jeyu@kernel.org
> > ---
> > kernel/module.c | 10 +++++++---
> > 1 file changed, 7 insertions(+), 3 deletions(-)
> >
> > --- a/kernel/module.c
> > +++ b/kernel/module.c
> > @@ -3751,9 +3751,13 @@ static int prepare_coming_module(struct
> > if (err)
> > return err;
> >
> > - blocking_notifier_call_chain(&module_notify_list,
> > - MODULE_STATE_COMING, mod);
> > - return 0;
> > + err = blocking_notifier_call_chain_robust(&module_notify_list,
> > + MODULE_STATE_COMING, MODULE_STATE_GOING, mod);
> > + err = notifier_to_errno(err);
> > + if (err)
> > + klp_module_going(mod);
> > +
> > + return err;
> > }
> >
> > static int unknown_module_param_cb(char *param, char *val, const char *modname,
> >
>
> This looks fine to me - klp_module_going() is only called after
> successful klp_module_coming(), and klp_module_going() is fine with
> mod->state still being MODULE_STATE_COMING here. Would be good to have
> livepatch folks double check. Which reminds me - Miroslav had pointed
> out in the past that if there is an error when calling the COMING
> notifiers, the GOING notifiers will be called while the mod->state is
> still MODULE_STATE_COMING. I've briefly looked through all the module
> notifiers and it looks like nobody is looking at mod->state directly
> at least.
>
> Acked-by: Jessica Yu <jeyu@kernel.org>

Looks good to me. klp_module_going() is already called in other
load_module() error scenarios so this should be fine from a livepatch
standpoint.

Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>

--
Josh

\
 
 \ /
  Last update: 2020-03-27 05:52    [W:0.103 / U:0.564 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site