From: Miroslav Benes <mbenes@suse.cz>
To: Jessica Yu <jeyu@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
x86@kernel.org, linux-kernel@vger.kernel.org,
rostedt@goodmis.org, mhiramat@kernel.org, bristot@redhat.com,
jbaron@akamai.com, torvalds@linux-foundation.org,
tglx@linutronix.de, mingo@kernel.org, namit@vmware.com,
hpa@zytor.com, luto@kernel.org, ard.biesheuvel@linaro.org,
jpoimboe@redhat.com
Subject: Re: [RESEND][PATCH v3 03/17] module: Properly propagate MODULE_STATE_COMING failure
Date: Fri, 27 Mar 2020 13:04:44 +0100 (CET) [thread overview]
Message-ID: <alpine.LSU.2.21.2003271257560.19979@pobox.suse.cz> (raw)
In-Reply-To: <20200325173519.GA5415@linux-8ccs>
On Wed, 25 Mar 2020, 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.
Yes, it is ok.
> 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.
Thanks for double-checking. I triple-checked and yes, it should be fine.
All module notifiers check the value from the function parameter and not
mod->state directly.
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
M
next prev parent reply other threads:[~2020-03-27 12:04 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-24 13:56 [RESEND][PATCH v3 00/17] Add static_call() Peter Zijlstra
2020-03-24 13:56 ` [RESEND][PATCH v3 01/17] notifier: Fix broken error handling pattern Peter Zijlstra
2020-03-24 13:56 ` [RESEND][PATCH v3 02/17] module: Fix up module_notifier return values Peter Zijlstra
2020-03-24 13:56 ` [RESEND][PATCH v3 03/17] module: Properly propagate MODULE_STATE_COMING failure Peter Zijlstra
2020-03-25 17:35 ` Jessica Yu
2020-03-27 4:51 ` Josh Poimboeuf
2020-03-27 12:04 ` Miroslav Benes [this message]
2020-03-24 13:56 ` [RESEND][PATCH v3 04/17] jump_label,module: Fix module lifetime for __jump_label_mod_text_reserved Peter Zijlstra
2020-03-24 13:56 ` [RESEND][PATCH v3 05/17] compiler.h: Make __ADDRESSABLE() symbol truly unique Peter Zijlstra
2020-03-24 13:56 ` [RESEND][PATCH v3 06/17] static_call: Add basic static call infrastructure Peter Zijlstra
2020-03-26 16:42 ` Nadav Amit
2020-03-26 17:01 ` Peter Zijlstra
2020-03-26 18:09 ` Nadav Amit
2020-03-26 18:28 ` Peter Zijlstra
2020-03-26 19:02 ` Nadav Amit
2020-03-26 19:13 ` Peter Zijlstra
2020-03-24 13:56 ` [RESEND][PATCH v3 07/17] static_call: Add inline " Peter Zijlstra
2020-03-26 15:54 ` Borislav Petkov
2020-03-24 13:56 ` [RESEND][PATCH v3 08/17] static_call: Avoid kprobes on inline static_call()s Peter Zijlstra
2020-03-24 13:56 ` [RESEND][PATCH v3 09/17] x86/static_call: Add out-of-line static call implementation Peter Zijlstra
2020-03-26 14:57 ` Borislav Petkov
2020-04-06 1:08 ` Fangrui Song
2020-04-06 11:04 ` Peter Zijlstra
2020-04-06 18:29 ` Nick Desaulniers
2020-03-24 13:56 ` [RESEND][PATCH v3 10/17] x86/static_call: Add inline static call implementation for x86-64 Peter Zijlstra
2020-03-26 15:17 ` Borislav Petkov
2020-03-26 16:06 ` Peter Zijlstra
2020-03-24 13:56 ` [RESEND][PATCH v3 11/17] static_call: Simple self-test Peter Zijlstra
2020-03-26 15:44 ` Borislav Petkov
2020-03-26 17:08 ` Peter Zijlstra
2020-03-26 17:33 ` Borislav Petkov
2020-03-24 13:56 ` [RESEND][PATCH v3 12/17] tracepoint: Optimize using static_call() Peter Zijlstra
2020-03-24 13:56 ` [RESEND][PATCH v3 13/17] x86/alternatives: Teach text_poke_bp() to emulate RET Peter Zijlstra
2020-03-24 13:56 ` [RESEND][PATCH v3 14/17] static_call: Add static_cond_call() Peter Zijlstra
2020-03-24 16:14 ` Linus Torvalds
2020-03-24 16:22 ` Andy Lutomirski
2020-03-24 16:33 ` Linus Torvalds
2020-03-24 17:03 ` Peter Zijlstra
2020-03-25 18:13 ` Peter Zijlstra
2020-03-25 18:26 ` Linus Torvalds
2020-03-25 19:34 ` hpa
2020-03-25 20:52 ` Linus Torvalds
2020-03-25 22:07 ` Peter Zijlstra
2020-03-24 16:54 ` Peter Zijlstra
2020-03-26 23:37 ` Rasmus Villemoes
2020-03-27 10:08 ` Peter Zijlstra
2020-03-27 13:25 ` Rasmus Villemoes
2020-03-24 13:56 ` [RESEND][PATCH v3 15/17] static_call: Handle tail-calls Peter Zijlstra
2020-03-24 13:56 ` [RESEND][PATCH v3 16/17] static_call: Allow early init Peter Zijlstra
2020-03-24 13:56 ` [RESEND][PATCH v3 17/17] x86/perf, static_call: Optimize x86_pmu methods Peter Zijlstra
2020-03-25 17:49 ` [RESEND][PATCH v3 00/17] Add static_call() Peter Zijlstra
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