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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Kaoru Fukui <k_fukui@highway.ne.jp>
Cc: <linuxppc-dev@lists.linuxppc.org>, <paulus@samba.org>,
	<cort@fsmlabs.com>
Subject: Re: Fwd: CPU features
Date: Sun, 1 Apr 2001 19:04:18 +0200	[thread overview]
Message-ID: <20010401170418.2024@smtp.wanadoo.fr> (raw)
In-Reply-To: <20010402002232.Postino-025103@smtp01.highway.ne.jp>


>
>Hi
>Thanks your great kernel works.
>Recently kernel source has spin_lock problem.
>
>I  needed the patch for kernel-2.4.3.pre8-SMP on Dual G4.
>
>Kernel Guys, Please look the patch or
>Please Look this problem.

Hrm.. your patch isn't good. I think I found the problem (but didn't
yet test. My proposed fix is in my rsync, please test and report).

Basically, pte_alloc() is meant to be called with the page table lock
held. It may itself unlock & re-lock it.

There are places in arch/ppc/mm/init.c where we call it (via map_page())
without the lock. That mean that we can go out of mapin_ram and paging_init
with a dangling page table lock held init init_mm, causing further calls
to __ioremap (or other things) to lockup as soon as they try to grab that
lock.

The fix would be to enclose those calls to map_page() with a
spin_lock(&init_mm.page_table_lock);
and
spin_unlock(&init_mm.page_table_lock);

Tell me what result you get with that.

ben.


** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/

  reply	other threads:[~2001-04-01 17:04 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-03-31  9:16 Fwd: CPU features Benjamin Herrenschmidt
2001-03-31 15:05 ` Kaoru Fukui
2001-03-31 15:35 ` Kaoru Fukui
2001-03-31 17:14   ` Benjamin Herrenschmidt
2001-04-01 12:30     ` Kaoru Fukui
2001-04-01 15:03       ` Benjamin Herrenschmidt
     [not found]       ` <20010401150348.13545@smtp.wanadoo.fr>
2001-04-01 15:22         ` Kaoru Fukui
2001-04-01 17:04           ` Benjamin Herrenschmidt [this message]
2001-04-01 18:32             ` Tony Mantler
2001-04-01 20:09               ` Benjamin Herrenschmidt
2001-04-01 21:45                 ` Tony Mantler
2001-04-01 22:07                   ` Benjamin Herrenschmidt
2001-04-01 22:24                     ` Tony Mantler
2001-04-01 22:40                       ` Benjamin Herrenschmidt
2001-04-01 19:11             ` Kaoru Fukui
2001-04-01 20:11               ` Benjamin Herrenschmidt
2001-04-02 18:46 ` Dan Malek
2001-04-02 21:58   ` Benjamin Herrenschmidt
  -- strict thread matches above, loose matches on Subject: below --
2001-04-01 15:46 Holger Bettag

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