From: Rusty Russell <rusty@rustcorp.com.au>
To: Jessica Yu <jeyu@redhat.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Seth Jennings <sjenning@redhat.com>,
Jiri Kosina <jikos@kernel.org>, Vojtech Pavlik <vojtech@suse.com>,
Miroslav Benes <mbenes@suse.cz>, Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
live-patching@vger.kernel.org, linux-kernel@vger.kernel.org,
Jessica Yu <jeyu@redhat.com>
Subject: Re: [PATCH 2/3] modules: set mod->state to GOING before going notifiers are called
Date: Thu, 10 Mar 2016 13:57:16 +1030 [thread overview]
Message-ID: <87a8m7ko6j.fsf@rustcorp.com.au> (raw)
In-Reply-To: <1457561637-24770-3-git-send-email-jeyu@redhat.com>
Jessica Yu <jeyu@redhat.com> writes:
> In load_module(), the going notifiers are called during error handling
> when an error occurs after the coming notifiers have already been called.
> However, a module's state is still MODULE_STATE_COMING when the going
> notifiers are called in the error path. To be consistent, also set
> mod->state to MODULE_STATE_GOING before calling the going notifiers.
>
> Signed-off-by: Jessica Yu <jeyu@redhat.com>
> ---
> kernel/module.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/kernel/module.c b/kernel/module.c
> index 1981ae0..9e80576 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -3494,6 +3494,9 @@ static int load_module(struct load_info *info, const char __user *uargs,
> return do_init_module(mod);
>
> coming_cleanup:
> + mutex_lock(&module_mutex);
> + mod->state = MODULE_STATE_GOING;
> + mutex_unlock(&module_mutex);
> blocking_notifier_call_chain(&module_notify_list,
> MODULE_STATE_GOING, mod);
Actually, reviewing this patch makes me realize it is wrong.
We rely on the state of the module being MODULE_STATE_COMING here:
static inline int strong_try_module_get(struct module *mod)
{
BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED);
if (mod && mod->state == MODULE_STATE_COMING)
return -EBUSY;
We will just have to document that the notifier can be called with
a module in MODULE_STATE_COMING if it never succeeded its
initialization.
Sorry for the previously false lead,
Rusty.
next prev parent reply other threads:[~2016-03-10 3:28 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-09 22:13 [PATCH 0/3] Livepatch module notifier cleanup Jessica Yu
2016-03-09 22:13 ` [PATCH 1/3] modules: split part of complete_formation() into prepare_coming_module() Jessica Yu
2016-03-10 22:41 ` Josh Poimboeuf
2016-03-09 22:13 ` [PATCH 2/3] modules: set mod->state to GOING before going notifiers are called Jessica Yu
2016-03-10 3:27 ` Rusty Russell [this message]
2016-03-10 5:08 ` Jessica Yu
2016-03-09 22:13 ` [PATCH 3/3] livepatch/module: remove livepatch module notifier Jessica Yu
2016-03-10 22:45 ` Josh Poimboeuf
2016-03-10 3:27 ` [PATCH 0/3] Livepatch module notifier cleanup Rusty Russell
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