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From: "\"Andrey Borzenkov\" " <arvidjaar@mail.ru>
To: "\"Andrew Morton\" " <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org,
	"\"Daniele Venzano\" " <webvenza@libero.it>
Subject: Re: 2.6.0-test1 devfs question
Date: Mon, 28 Jul 2003 11:13:38 +0400	[thread overview]
Message-ID: <E19h2CQ-0009YQ-00.arvidjaar-mail-ru@f12.mail.ru> (raw)


> 
> The patch is broken - 2.4 does /dev/md/2 as well.
> 
> So what is the bug?  Why are people suddenly having problems with this?
> 

Daniele did some debugging, result is:

=================
Buggy config
------------
GRUB command line: kernel (hd0,1)/testing root=/dev/md2
video=radeonfb:1024x768-32@60
As output there is only (copied by hand):

[...]

raid1: raid set md2 active with 2 out of 2 mirrors
md: ... autorun DONE.
create_dev: name=/dev/root dev=902 dname=md2
VFS: cannot open root device "md2" or md2
please append a correct "root=" boot option
Kernel panic: VFS: unable to mount root fs on md2
<STOP>
==================

the bug is almost for sure in init/do_mount_devfs.c:read_dir; it
allocates static buffer of size at most 2**MAX_ORDER and tries to
read the whole dir at once. md driver creates all minors in md_init
i.e. 256 (2**MINORBITS). MAX_ORDER default is 11 so we have at most
2K which is enough for appr. 200 entries; 256 do not fit :)

Daniel, please, could you change read_dir to just allocate bigger
buffer - 4K should do - and test once more?

I'll see what can be done. Anyone sees reason why normal directory
scan won't work here?

-andrey 


             reply	other threads:[~2003-07-28  7:01 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-07-28  7:13 "Andrey Borzenkov"  [this message]
2003-07-28  7:22 ` Andrew Morton
2003-07-28 15:59   ` [BUG SQUISHED] " Daniele Venzano
  -- strict thread matches above, loose matches on Subject: below --
2003-07-26 19:51 Andrey Borzenkov
2003-07-26 20:50 ` Andrew Morton
2003-07-26 22:30   ` Andrey Borzenkov
2003-07-27  8:58     ` Daniele Venzano
2003-07-25 18:53 Balram Adlakha
2003-07-26 10:45 ` Wiktor Wodecki
     [not found]   ` <20030726175214.GA2535@localhost.localdomain>
     [not found]     ` <20030726183750.GB789@gmx.de>
     [not found]       ` <20030726201919.GA5166@localhost.localdomain>
2003-07-26 20:35         ` Wiktor Wodecki
2003-07-25 11:08 Wiktor Wodecki
2003-07-25 11:18 ` Wiktor Wodecki
2003-07-26 11:12 ` Daniele Venzano
2003-07-26 18:25   ` Andrew Morton
2003-07-27 11:17     ` Alan Cox

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