From: Andrew Morton <akpm@osdl.org>
To: "Art Haas" <ahaas@airmail.net>
Cc: linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org
Subject: Re: Problem with recent changes to fs/dcache.c
Date: Thu, 29 Apr 2004 20:39:01 -0700 [thread overview]
Message-ID: <20040429203901.4cd21fdc.akpm@osdl.org> (raw)
In-Reply-To: <20040430020525.GI27793@artsapartment.org>
"Art Haas" <ahaas@airmail.net> wrote:
>
> I run linux on a SparcStation SS20 in addition to a PC, and found that
> none of the 2.6.6-rc kernels would boot. After trying the latest -rc3
> kernel and seeing it fail also, my debugging quest began. Adding a few
> printk() statements pointed the problem to be in fs/dcache.c in the
> vfs_caches_init() function. The 1.69->1.70 changes to this file added in
> a call to nr_free_pages() and used that result to adjust the global
> mempages variable. This change caused the boot failures.
>
> The printk() statements I'd added showed that vfs_caches_init() was
> being called with 'mempages' set to 46073. The nr_free_pages() call
> returned 127661, and this value being subtracted from mempages went
> negative, but the value is unsigned, so mempages became enormous. Things
> ended up getting stuck in the inode_init() call down a bit, having
> seeming survived the dcache_init() call only because of values
> wrapping around.
>
> I commented out the 'mempages -= reserve;' line in the file, and the
> boot continued along. Unfortunately I encounter a kernel trap when
> mounting the hard drives, so there are other problems still needing to
> be looked at.
>
> The possiblity of nr_free_pages() being larger than mempages looks like
> a silent bug that was tripped. If not, then another bug in the Sparc
> port may be responsible for values being used in these functions. The
> memory-management gurus can take a peek and see what they find.
Yes, something's bust in the sparc port's calculation of num_physpages.
Clearly it should be larger than nr_free_pages().
next prev parent reply other threads:[~2004-04-30 3:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-04-30 2:05 Art Haas
2004-04-30 3:39 ` Andrew Morton [this message]
2004-04-30 20:41 ` Art Haas
2004-04-30 21:41 ` Andrew Morton
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