From: Dave Hansen <haveblue@us.ibm.com>
To: "Sridhar Samudrala [imap]" <sri@us.ibm.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: CONFIG_DEBUG_PAGEALLOC and virt_addr_valid()
Date: Thu, 01 Apr 2004 11:30:24 -0800 [thread overview]
Message-ID: <1080847824.24060.39.camel@nighthawk> (raw)
In-Reply-To: <Pine.LNX.4.58.0404011105120.1956@localhost.localdomain>
On Thu, 2004-04-01 at 11:11, Sridhar Samudrala wrote:
> When CONFIG_DEBUG_PAGEALLOC is enabled, i am noticing that virt_addr_valid()
> (called from sctp_is_valid_kaddr()) is returning true even for freed objects.
> Is this a bug or expected behavior?
It's expected. Right now it just makes sure the address translates to a
valid pfn. Figuring out whether there are actually pagetables
underneath that address would require a pagetable walk.
Don't we unmap things when they are free'd with CONFIG_DEBUG_PAGEALLOC?
I guess we could add a pagetable walk in the debug case to
virt_addr_valid(), but it would probably make CONFIG_DEBUG_PAGEALLOC
even more of a dog than it already is.
-- Dave
next prev parent reply other threads:[~2004-04-01 19:33 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-04-01 19:11 CONFIG_DEBUG_PAGEALLOC and virt_addr_valid() Sridhar Samudrala
2004-04-01 19:30 ` Dave Hansen [this message]
2004-04-01 19:44 ` Christoph Hellwig
2004-04-01 20:58 ` Sridhar Samudrala
2004-04-01 21:15 ` Richard B. Johnson
2004-04-02 0:29 ` Andrew Morton
2004-04-02 1:39 ` Sridhar Samudrala
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