From: Ingo Molnar <mingo@elte.hu>
To: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Rusty Russell <rusty@rustcorp.com.au>,
Pekka Enberg <penberg@cs.helsinki.fi>,
"Justin P. Mattock" <justinmattock@gmail.com>,
linux-kernel@vger.kernel.org,
Jeff Chua <jeff.chua.linux@gmail.com>
Subject: Re: [PATCH] stop_machine/cpu hotplug: fix disable_nonboot_cpus
Date: Wed, 7 Jan 2009 16:23:33 +0100 [thread overview]
Message-ID: <20090107152333.GC5771@elte.hu> (raw)
In-Reply-To: <20090107151946.GA25560@osiris.boeblingen.de.ibm.com>
* Heiko Carstens <heiko.carstens@de.ibm.com> wrote:
> From: Heiko Carstens <heiko.carstens@de.ibm.com>
>
> disable_nonboot_cpus calls _cpu_down. But _cpu_down requires that the
> caller already created the stop_machine workqueue (like cpu_down does).
> Otherwise a call to stop_machine will lead to accesses to random memory
> regions.
btw., i got this crash earlier today:
CPU0 attaching sched-domain:
domain 0: span 0-1 level CPU
groups: 0 1
CPU1 attaching sched-domain:
domain 0: span 0-1 level CPU
groups: 1 0
eth0: no IPv6 routers present
BUG: Bad page state in process cc1 pfn:00879
page:c101b894 flags:00000400 count:0 mapcount:0 mapping:(null) index:0
Pid: 3060, comm: cc1 Not tainted 2.6.28-tip-07641-gb97d41d-dirty #14985
Call Trace:
[<c016ce8b>] bad_page+0xcf/0xe5
[<c016d3b4>] free_pages_check+0xa7/0xc5
[<c016d400>] free_hot_cold_page+0x2e/0x138
[<c014751c>] ? __lock_acquire+0x127/0x29d
[<c016d558>] free_hot_page+0xf/0x11
[<c0170963>] put_page+0x76/0x7c
[<c0185071>] ? constant_test_bit+0x9/0x20
[<c0187149>] kfree+0x30/0xe5
[<c0164993>] ? trace_hardirqs_on+0x8/0x1c
[<c01547dd>] free_user_ns+0x1d/0x20
[<c01547c0>] ? free_user_ns+0x0/0x20
[<c02c7a41>] kref_put+0x18/0x22
[<c0132d4c>] put_user_ns+0x16/0x18
[<c0132f52>] free_uid+0x59/0xc8
[<c0136239>] ? groups_free+0x36/0x3a
[<c0140406>] put_cred_rcu+0x5f/0x70
[<c01598fb>] __rcu_process_callbacks+0x168/0x1f8
[<c03031be>] ? isicom_tx+0x0/0x31f
[<c01599b1>] rcu_process_callbacks+0x26/0x46
[<c012f11d>] __do_softirq+0x9d/0x139
[<c012f080>] ? __do_softirq+0x0/0x139
<IRQ> [<c012efe2>] ? irq_exit+0x4c/0x83
[<c05cc586>] ? __irqentry_text_start+0x6e/0x7c
[<c0103f61>] ? apic_timer_interrupt+0x2d/0x34
and i applied your patch (from the other thread) and never saw this bug
again.
So if it's the same bug (it appears to be) then you have my:
Tested-by: Ingo Molnar <mingo@elte.hu>
Ingo
next prev parent reply other threads:[~2009-01-07 15:24 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-07 0:12 [ 286.547348] BUG: unable to handle kernel paging request at 6b6b6b6b Justin P. Mattock
2009-01-07 6:48 ` Pekka Enberg
2009-01-07 8:13 ` Justin P. Mattock
2009-01-07 8:30 ` Pekka Enberg
2009-01-07 9:15 ` Heiko Carstens
2009-01-07 9:19 ` Pekka Enberg
2009-01-07 11:36 ` Jeff Chua
2009-01-07 12:27 ` Heiko Carstens
2009-01-07 13:51 ` Jeff Chua
2009-01-07 15:19 ` [PATCH] stop_machine/cpu hotplug: fix disable_nonboot_cpus Heiko Carstens
2009-01-07 15:23 ` Ingo Molnar [this message]
2009-01-07 15:30 ` Frédéric Weisbecker
2009-01-07 15:52 ` Justin P. Mattock
2009-01-08 5:13 ` Justin P. Mattock
2009-01-07 15:28 ` [ 286.547348] BUG: unable to handle kernel paging request at 6b6b6b6b Justin P. Mattock
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