public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: Masami Hiramatsu <mhiramat@redhat.com>
To: Adrian Bunk <bunk@kernel.org>
Cc: ananth@in.ibm.com, anil.s.keshavamurthy@intel.com,
	davem@davemloft.net, bugme-daemon@bugzilla.kernel.org,
	jean-marc LACROIX <jeanmarc.lacroix@free.Fr>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
	Arjan van de Ven <arjan@linux.intel.com>
Subject: Re: [Bug 10489] Kprobe smoke test lockdep warning
Date: Mon, 21 Apr 2008 18:54:12 -0400	[thread overview]
Message-ID: <480D1B14.7070806@redhat.com> (raw)
In-Reply-To: <20080421150656.GJ6011@cs181133002.pp.htv.fi>

Thank you for reporting.

Actually, kprobes tries to fixup thread's flags in post_kprobe_handler
(which is called from kprobe_exceptions_notify) by
trace_hardirqs_fixup_flags(pt_regs->flags). However, even the irq flag
is set in pt_regs->flags, true hardirq is still off until returning
from do_debug. Thus, lockdep assumes that hardirq is off without annotation.

IMHO, one possible solution is that fixing hardirq flags right after
notify_die in do_debug instead of in post_kprobe_handler.

Thanks,


-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com


  parent reply	other threads:[~2008-04-21 22:54 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-04-21 15:06 [Bug 10489] Kprobe smoke test lockdep warning Adrian Bunk
2008-04-21 15:13 ` Vegard Nossum
2008-04-21 22:54 ` Masami Hiramatsu [this message]
2008-04-22 13:09   ` Peter Zijlstra
2008-04-22 13:26     ` Peter Zijlstra
2008-04-22 15:25       ` Masami Hiramatsu
2008-04-22 16:05         ` Peter Zijlstra
2008-04-22 16:23           ` Masami Hiramatsu
2008-04-22 19:51             ` Masami Hiramatsu
2008-04-22 16:18     ` Masami Hiramatsu
2008-07-15  9:19       ` Ingo Molnar

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=480D1B14.7070806@redhat.com \
    --to=mhiramat@redhat.com \
    --cc=ananth@in.ibm.com \
    --cc=anil.s.keshavamurthy@intel.com \
    --cc=arjan@linux.intel.com \
    --cc=bugme-daemon@bugzilla.kernel.org \
    --cc=bunk@kernel.org \
    --cc=davem@davemloft.net \
    --cc=jeanmarc.lacroix@free.Fr \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@elte.hu \
    /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