From: Daniel Bristot de Oliveira <bristot@redhat.com>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Steven Rostedt (VMware)" <rostedt@goodmis.org>,
Jiri Kosina <jkosina@suse.cz>,
Josh Poimboeuf <jpoimboe@redhat.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Chris von Recklinghausen <crecklin@redhat.com>,
Jason Baron <jbaron@akamai.com>, Scott Wood <swood@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Clark Williams <williams@redhat.com>,
x86@kernel.org
Subject: Re: [PATCH V4 8/9] jump_label: Batch updates if arch supports it
Date: Wed, 6 Feb 2019 16:59:42 +0100 [thread overview]
Message-ID: <df5a556f-332d-b014-b5ea-44968860acf5@redhat.com> (raw)
In-Reply-To: <20190206153418.722cc7f4a83d0e48c8dca552@kernel.org>
On 2/6/19 7:34 AM, Masami Hiramatsu wrote:
> On Mon, 4 Feb 2019 20:59:01 +0100
> Daniel Bristot de Oliveira <bristot@redhat.com> wrote:
>
>> --- a/kernel/jump_label.c
>> +++ b/kernel/jump_label.c
>> @@ -407,6 +407,7 @@ bool jump_label_can_update_check(struct jump_entry *entry, bool init)
>> return 0;
>> }
>>
>> +#ifndef HAVE_JUMP_LABEL_BATCH
>> static void __jump_label_update(struct static_key *key,
>> struct jump_entry *entry,
>> struct jump_entry *stop,
>> @@ -419,6 +420,34 @@ static void __jump_label_update(struct static_key *key,
>> }
>> }
>> }
>> +#else
>> +static void __jump_label_update(struct static_key *key,
>> + struct jump_entry *entry,
>> + struct jump_entry *stop,
>> + bool init)
>> +{
>> + for_each_label_entry(key, entry, stop) {
>> +
>> + if (!jump_label_can_update_check(entry, init))
>> + continue;
>> +
>> + if (arch_jump_label_transform_queue(entry,
>> + jump_label_type(entry)))
>> + continue;
>> +
>> + /*
>> + * Queue's overflow: Apply the current queue, and then
>> + * queue again. If it stills not possible to queue, BUG!
>> + */
>> + arch_jump_label_transform_apply();
>> + if (!arch_jump_label_transform_queue(entry,
>> + jump_label_type(entry))) {
>> + BUG();
>
> Please do not relay on BUG(), since in both case (applied or not),
> jump_label is not critical for normal operation. I think you should use
> WARN_ONCE() here and lock the jump_label so that root user can report it
> to us :)
Oops! I wrote a patch changing this, removing the BUG(). It was a request from
steve, but somehow I ended up missing it.
Thanks for reviewing this...
My bad, sorry :-(
-- Daniel
> Thank you,
>
>
next prev parent reply other threads:[~2019-02-06 15:59 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-04 19:58 [PATCH V4 0/9] x86/jump_label: Bound IPIs sent when updating a static key Daniel Bristot de Oliveira
2019-02-04 19:58 ` [PATCH V4 1/9] jump_label: Add for_each_label_entry helper Daniel Bristot de Oliveira
2019-02-04 19:58 ` [PATCH V4 2/9] jump_label: Add the jump_label_can_update_check() helper Daniel Bristot de Oliveira
2019-02-05 7:22 ` Borislav Petkov
2019-02-05 13:50 ` Daniel Bristot de Oliveira
2019-02-05 21:13 ` Borislav Petkov
2019-02-07 13:21 ` Daniel Bristot de Oliveira
2019-02-07 14:08 ` Borislav Petkov
2019-02-07 17:00 ` Daniel Bristot de Oliveira
2019-02-07 17:08 ` Borislav Petkov
2019-02-04 19:58 ` [PATCH V4 3/9] x86/jump_label: Move checking code away from __jump_label_transform() Daniel Bristot de Oliveira
2019-02-05 7:33 ` Borislav Petkov
2019-02-05 15:22 ` Daniel Bristot de Oliveira
2019-02-15 10:05 ` Daniel Bristot de Oliveira
2019-02-04 19:58 ` [PATCH V4 4/9] x86/jump_label: Add __jump_label_set_jump_code() helper Daniel Bristot de Oliveira
2019-02-04 19:58 ` [PATCH V4 5/9] x86/alternative: Split text_poke_bp() into tree steps Daniel Bristot de Oliveira
2019-02-06 19:07 ` Borislav Petkov
2019-02-08 0:11 ` Steven Rostedt
2019-02-08 0:15 ` Steven Rostedt
2019-02-15 12:47 ` Daniel Bristot de Oliveira
2019-02-21 15:26 ` Steven Rostedt
2019-02-04 19:58 ` [PATCH V4 6/9] jump_label: Sort entries of the same key by the code Daniel Bristot de Oliveira
2019-02-04 19:59 ` [PATCH V4 7/9] x86/alternative: Batch of patch operations Daniel Bristot de Oliveira
2019-02-14 12:53 ` Borislav Petkov
2019-02-14 14:06 ` Steven Rostedt
2019-02-14 14:30 ` Borislav Petkov
2019-02-14 14:40 ` Steven Rostedt
2019-02-14 14:54 ` Borislav Petkov
2019-02-15 16:00 ` Daniel Bristot de Oliveira
2019-02-15 17:20 ` Steven Rostedt
2019-02-04 19:59 ` [PATCH V4 8/9] jump_label: Batch updates if arch supports it Daniel Bristot de Oliveira
2019-02-06 6:34 ` Masami Hiramatsu
2019-02-06 15:59 ` Daniel Bristot de Oliveira [this message]
2019-02-14 13:33 ` Borislav Petkov
2019-02-04 19:59 ` [PATCH V4 9/9] x86/jump_label: Batch jump label updates Daniel Bristot de Oliveira
2019-02-06 6:29 ` Masami Hiramatsu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=df5a556f-332d-b014-b5ea-44968860acf5@redhat.com \
--to=bristot@redhat.com \
--cc=bp@alien8.de \
--cc=crecklin@redhat.com \
--cc=gregkh@linuxfoundation.org \
--cc=hpa@zytor.com \
--cc=jbaron@akamai.com \
--cc=jkosina@suse.cz \
--cc=jpoimboe@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mhiramat@kernel.org \
--cc=mingo@redhat.com \
--cc=mtosatti@redhat.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=swood@redhat.com \
--cc=tglx@linutronix.de \
--cc=williams@redhat.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).