From: Matthew Wilcox <matthew@wil.cx>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Rabin Vincent <rabin@rab.in>, lkml <linux-kernel@vger.kernel.org>,
penberg@cs.helsinki.fi, cl@linux-foundation.org,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
linux-arch@vger.kernel.org
Subject: Re: start_kernel(): bug: interrupts were enabled early
Date: Wed, 31 Mar 2010 15:17:55 -0600 [thread overview]
Message-ID: <20100331211754.GC32165@parisc-linux.org> (raw)
In-Reply-To: <4BB3B8FC.1020608@zytor.com>
On Wed, Mar 31, 2010 at 02:05:00PM -0700, H. Peter Anvin wrote:
> What I note is that lib/rwsem-spinlock.c seems to be rather inconsistent
> in its use of spin_lock_irqsave/spin_lock_irqrestore versus
> spin_lock_irq/spin_unlock_irq... in fact, __down_read is the *only*
> place where we use the latter as opposed to the former.
>
> Is that a bug? If so, it would certainly explain this behavior.
It's based on down_read() and down_write() not being callable from
interrupt context, or with interrupts disabled (since they can sleep).
up_read(), up_write(), down_read_trylock(), down_write_trylock(),
downgrade_write() can all be called from interrupt context since they
cannot sleep.
--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
next prev parent reply other threads:[~2010-03-31 21:17 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-25 19:41 start_kernel(): bug: interrupts were enabled early Rabin Vincent
2010-03-31 20:40 ` Andrew Morton
2010-03-31 20:47 ` Yinghai Lu
2010-03-31 20:52 ` Andrew Morton
2010-03-31 21:12 ` H. Peter Anvin
2010-03-31 21:28 ` Andrew Morton
2010-03-31 22:35 ` Benjamin Herrenschmidt
2010-04-01 16:13 ` Linus Torvalds
2010-04-01 14:27 ` Andrew Morton
2010-04-01 20:12 ` Linus Torvalds
2010-04-02 14:46 ` David Howells
2010-04-02 14:54 ` Linus Torvalds
2010-04-07 19:09 ` Kevin Hilman
2010-04-07 19:09 ` Kevin Hilman
2010-04-08 15:55 ` Américo Wang
2010-04-08 15:55 ` Américo Wang
2010-03-31 21:01 ` Matthew Wilcox
2010-03-31 21:05 ` H. Peter Anvin
2010-03-31 21:17 ` Matthew Wilcox [this message]
2010-03-31 21:42 ` Christoph Lameter
2010-03-31 21:54 ` Russell King
2010-03-31 21:57 ` H. Peter Anvin
2010-03-31 21:57 ` H. Peter Anvin
2010-03-31 22:30 ` Russell King
2010-03-31 22:37 ` Benjamin Herrenschmidt
2010-03-31 22:49 ` Andrew Morton
2010-04-01 1:17 ` Benjamin Herrenschmidt
2010-03-31 22:26 ` Andrew Morton
2010-04-01 6:26 ` H. Peter Anvin
2010-04-01 3:33 ` Andrew Morton
2010-04-01 6:48 ` Benjamin Herrenschmidt
2010-04-01 11:06 ` David Howells
2010-04-01 15:55 ` Christoph Lameter
2010-04-01 23:00 ` Benjamin Herrenschmidt
2010-04-01 16:15 ` H. Peter Anvin
2010-04-01 6:50 ` Benjamin Herrenschmidt
2010-03-31 22:36 ` Benjamin Herrenschmidt
2010-04-01 15:57 ` Christoph Lameter
2010-03-31 21:05 ` Russell King
2010-03-31 21:08 ` H. Peter Anvin
2010-03-31 21:08 ` H. Peter Anvin
2010-03-31 22:58 ` David Howells
2010-04-01 9:41 ` Jamie Lokier
2010-04-01 10:50 ` David Howells
2010-04-01 11:23 ` Matthew Wilcox
2010-03-31 22:31 ` Benjamin Herrenschmidt
2010-03-31 22:36 ` H. Peter Anvin
-- strict thread matches above, loose matches on Subject: below --
2006-10-18 15:50 Martin Michlmayr
2006-10-18 16:51 ` mlachwani
2006-10-18 18:14 ` Ralf Baechle
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=20100331211754.GC32165@parisc-linux.org \
--to=matthew@wil.cx \
--cc=akpm@linux-foundation.org \
--cc=benh@kernel.crashing.org \
--cc=cl@linux-foundation.org \
--cc=hpa@zytor.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=penberg@cs.helsinki.fi \
--cc=rabin@rab.in \
--cc=yinghai@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.