From: Thomas Gleixner <tglx@linutronix.de>
To: Daniel Wagner <daniel.wagner@bmw-carit.de>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v0] softirq: Call trace_preempt_on manually to prevent lockdep splatter
Date: Tue, 2 Jun 2015 21:37:58 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.11.1506022137090.20347@nanos> (raw)
In-Reply-To: <1432804174-16321-1-git-send-email-daniel.wagner@bmw-carit.de>
On Thu, 28 May 2015, Daniel Wagner wrote:
> __do_softirq() uses __local_bh_disable_ip(SOFTIRQ_OFFSET) to disable
> SOFTIRQs and signaling that softirqs are served.
>
> When done, __do_softirq() calls __local_bh_enable(SOFTIRQ_OFFSET)
> to enable them again. The reason it does not call
> __local_bh_enable_ip(SOFTIRQ_OFFSET) is because __local_bh_enable_ip()
> would process still-pending softirqs.
>
> Now, we face the same problem as in __local_bh_disable_ip()
> with the preempt tracer hooking into preempt_count_sub(). This
> will case lockdep warning, when for example the kernel is configured
> to run all IRQs as threads and preemptoff tracer is activated:
....
> Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
prev parent reply other threads:[~2015-06-02 19:38 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-20 8:46 lockdep warning: threadirqs and preemptoff tracer Daniel Wagner
2015-05-26 11:52 ` Daniel Wagner
2015-05-26 12:32 ` Steven Rostedt
2015-05-26 12:51 ` Daniel Wagner
2015-05-26 13:04 ` Steven Rostedt
2015-05-28 9:09 ` [PATCH v0] softirq: Call trace_preempt_on manually to prevent lockdep splatter Daniel Wagner
2015-06-02 19:37 ` Thomas Gleixner [this message]
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=alpine.DEB.2.11.1506022137090.20347@nanos \
--to=tglx@linutronix.de \
--cc=daniel.wagner@bmw-carit.de \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.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
all inboxes | Powered by JetHome®