From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Nathan Lynch <ntl@pobox.com>
Cc: linuxppc-dev@ozlabs.org
Subject: Re: lockdep badness
Date: Fri, 25 Jul 2008 08:44:56 +1000 [thread overview]
Message-ID: <1216939496.11188.58.camel@pasglop> (raw)
In-Reply-To: <20080724192300.GE9594@localdomain>
On Thu, 2008-07-24 at 14:23 -0500, Nathan Lynch wrote:
> I'm seeing warnings from the lockdep code itself in recent kernels on
> a Power6 blade (v2.6.26 and benh's -next branch).
>
> Something to do with powerpc's "lazy" interrupt-disabling, perhaps?
>
> A couple of stack traces below, the first is from benh's tree, the
> second is from 2.6.26. The lockdep self-tests all pass at boot.
Interesting.
> [c0000000e787bc20] [c0000000e787bc70] 0xc0000000e787bc70 (unreliable)
> [c0000000e787bca0] [c0000000000b5ac8] .lock_release+0x7c/0x208
> [c0000000e787bd50] [c0000000005e12c0] ._spin_unlock_irqrestore+0x34/0x94
> [c0000000e787bde0] [c00000000004d648] .pSeries_log_error+0x380/0x3f0
> [c0000000e787bef0] [c00000000004d8e4] .rtasd+0x98/0x100
> [c0000000e787bf90] [c000000000029d20] .kernel_thread+0x4c/0x68
> Instruction dump:
This one is one I haven't managed to reproduce and didn't quite find out
what could be causing it, but it was already reported by Badari (and in
fact is referenced as a regression in Rafael list).
> Call Trace:
> [c00000000fffbb10] [c00000000fffbbb0] 0xc00000000fffbbb0 (unreliable)
> [c00000000fffbbb0] [c0000000005d8824] ._spin_unlock_irq+0x40/0x68
> [c00000000fffbc40] [c000000000426708] .ipr_ioa_reset_done+0x218/0x2ac
> [c00000000fffbd00] [c00000000041bdb8] .ipr_reset_ioa_job+0xc8/0xf4
> [c00000000fffbd90] [c000000000424ffc] .ipr_isr+0x280/0x628
> [c00000000fffbe50] [c0000000000ccc70] .handle_IRQ_event+0x58/0xd4
> [c00000000fffbef0] [c0000000000cef4c] .handle_fasteoi_irq+0x128/0x1c8
> [c00000000fffbf90] [c000000000029918] .call_handle_irq+0x1c/0x2c
> [c000000000a63a20] [c00000000000d9cc] .do_IRQ+0x138/0x248
> [c000000000a63ad0] [c000000000004ca8] hardware_interrupt_entry+0x28/0x2c
> --- Exception: 501 at .raw_local_irq_restore+0x8c/0xa4
> LR = .cpu_idle+0x140/0x210
> [c000000000a63e60] [c0000000005da07c] .rest_init+0x7c/0x98
> [c000000000a63ee0] [c000000000866f10] .start_kernel+0x488/0x4b0
> [c000000000a63f90] [c000000000008584] .start_here_common+0x4c/0xc8
> Instruction dump:
This one is new to me. I will have a look. What machine is this ?
I suspect the error is to do spin_lock/unlock_irq rather than
save/restore variants at IRQ time, which would be an IPR bug... or
rather something legal that Ingo decided shouldn't be anymore :-)
Cheers,
Ben.
next prev parent reply other threads:[~2008-07-24 22:45 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-24 19:23 lockdep badness Nathan Lynch
2008-07-24 19:38 ` Nathan Lynch
2008-07-24 22:47 ` Benjamin Herrenschmidt
2008-07-24 22:44 ` Benjamin Herrenschmidt [this message]
2008-07-24 23:00 ` Nathan Lynch
2008-07-24 23:04 ` Arnd Bergmann
2008-07-25 12:59 ` Sebastien Dugue
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=1216939496.11188.58.camel@pasglop \
--to=benh@kernel.crashing.org \
--cc=linuxppc-dev@ozlabs.org \
--cc=ntl@pobox.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;
as well as URLs for NNTP newsgroup(s).