From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
Anton Arapov <anton@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Peter Zijlstra <peterz@infradead.org>,
Roland McGrath <roland@hack.frob.com>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] ptrace: fix set_task_blockstep()->update_debugctlmsr() logic
Date: Fri, 03 Aug 2012 20:28:14 +0200 [thread overview]
Message-ID: <501C183E.5000303@linutronix.de> (raw)
In-Reply-To: <20120803173830.GA22687@redhat.com>
On 08/03/2012 07:38 PM, Oleg Nesterov wrote:
>>> update_debugctlmsr(debugctl);
>>> + local_irq_enable();
>>
>> wouldn't preempt_disable() be enough?
>
> preempt_disable() can't help if interrupt handler changes
> other bits in between?
So perf() uses this register as well. Since perf() uses the raw
primitives (raw_spin_lock()) shouldn't you do the same? If I recall
correctly (but it is Friday and late) local_irq_enable() wouldn't
disable irqs on RT and perf takes the raw lock so the irqs there should
be really disabled.
>
> Oleg.
Sebastian
next prev parent reply other threads:[~2012-08-03 18:28 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-03 16:29 [PATCH 0/2] ptrace: DEBUGCTLMSR_BTF fixes Oleg Nesterov
2012-08-03 16:29 ` [PATCH 1/2] ptrace: introduce set_task_blockstep() helper Oleg Nesterov
2012-08-03 16:29 ` [PATCH 2/2] ptrace: fix set_task_blockstep()->update_debugctlmsr() logic Oleg Nesterov
2012-08-03 16:43 ` Sebastian Andrzej Siewior
2012-08-03 17:38 ` Oleg Nesterov
2012-08-03 18:28 ` Sebastian Andrzej Siewior [this message]
2012-08-07 15:13 ` Oleg Nesterov
2012-08-07 9:41 ` Sebastian Andrzej Siewior
2012-08-07 10:52 ` Sebastian Andrzej Siewior
2012-08-07 15:15 ` Oleg Nesterov
2012-08-07 15:29 ` Sebastian Andrzej Siewior
2012-08-07 15:31 ` Oleg Nesterov
2012-08-07 15:12 ` Oleg Nesterov
2012-08-06 16:14 ` [PATCH 0/2] ptrace: DEBUGCTLMSR_BTF fixes Sebastian Andrzej Siewior
2012-08-07 15:15 ` Oleg Nesterov
2012-08-07 15:38 ` Sebastian Andrzej Siewior
2012-08-07 15:46 ` Oleg Nesterov
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=501C183E.5000303@linutronix.de \
--to=bigeasy@linutronix.de \
--cc=ananth@in.ibm.com \
--cc=anton@redhat.com \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=oleg@redhat.com \
--cc=peterz@infradead.org \
--cc=roland@hack.frob.com \
--cc=srikar@linux.vnet.ibm.com \
/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