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From: David Mosberger <davidm@napali.hpl.hp.com>
To: linux-ia64@vger.kernel.org
Subject: Re: [PATCH] 2.4.25: BUG(): Use guard page instead of page 0
Date: Thu, 19 Feb 2004 01:14:59 +0000	[thread overview]
Message-ID: <16436.3603.827198.821944@napali.hpl.hp.com> (raw)
In-Reply-To: <20040218221302.GA87364@dragonfly.csd.sgi.com>

>>>>> On Wed, 18 Feb 2004 14:13:03 -0800, Jason Uhlenkott <jasonuhl@sgi.com> said:

  Jason> The ia64 BUG macro deliberately writes to address 0 in order to
  Jason> trigger a page fault and an Oops.  This won't work if the process has
  Jason> mapped something into page zero:  We'll just print the "kernel BUG"
  Jason> message and continue (after having stomped on whatever user memory was
  Jason> at address 0).

  Jason> A solution is to write to the guard page in region 5, which is
  Jason> guaranteed to trigger a page fault.

The 2.6 kernel uses __builtin_trap(), which is even better (when available).

	--david

  reply	other threads:[~2004-02-19  1:14 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-02-18 22:13 [PATCH] 2.4.25: BUG(): Use guard page instead of page 0 Jason Uhlenkott
2004-02-19  1:14 ` David Mosberger [this message]
2004-03-04 23:25 ` Bjorn Helgaas
2004-03-04 23:41 ` Keith Owens
2004-03-04 23:57 ` Bjorn Helgaas
2004-03-05  0:05 ` David Mosberger
2004-03-05  0:06 ` David Mosberger

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