dmraid adventures and 'challenges'

[Chris Chabot]

After some experimenting i 'hit gold' on how to kind of make it boot the 
latest kernel again:

1) gunzip, cpio 2364 initrd
2) ditto for 2527 initrd (different directory)
3) copy over *.ko files from 2527 directory into 2364 directory
4) cpio, gzip resulting old nash/insmod/modprobe/init+new kernel modules 
into a new 2527 initrd

and presto .. it boots!

Only anoyance left (well appart from having to jump thru those hoops) is 
that it now shouts at me at boot:

=============================================
[ INFO: possible recursive locking detected ]
---------------------------------------------
init/1 is trying to acquire lock:
 (&md->io_lock){----}, at: [<ffffffff880d9654>] dm_request+0x25/0x130 [dm_mod]

but task is already holding lock:
 (&md->io_lock){----}, at: [<ffffffff880d9654>] dm_request+0x25/0x130 [dm_mod]

other info that might help us debug this:
1 lock held by init/1:
 #0:  (&md->io_lock){----}, at: [<ffffffff880d9654>] dm_request+0x25/0x130 [dm_mod]

stack backtrace:

Call Trace:
 [<ffffffff8026e73d>] show_trace+0xae/0x319
 [<ffffffff8026e9bd>] dump_stack+0x15/0x17
 [<ffffffff802a7f00>] __lock_acquire+0x135/0xa5f
 [<ffffffff802a8dcd>] lock_acquire+0x4b/0x69
 [<ffffffff802a58f9>] down_read+0x3e/0x4a
 [<ffffffff880d9654>] :dm_mod:dm_request+0x25/0x130
 [<ffffffff8021cf45>] generic_make_request+0x21a/0x235
 [<ffffffff880d8402>] :dm_mod:__map_bio+0xca/0x104
 [<ffffffff880d8e48>] :dm_mod:__split_bio+0x16a/0x36b
 [<ffffffff880d974c>] :dm_mod:dm_request+0x11d/0x130
 [<ffffffff8021cf45>] generic_make_request+0x21a/0x235
 [<ffffffff80235eb7>] submit_bio+0xcc/0xd5
 [<ffffffff8021b381>] submit_bh+0x100/0x124
 [<ffffffff802e1a3c>] block_read_full_page+0x283/0x2a1
 [<ffffffff802e40df>] blkdev_readpage+0x13/0x15
 [<ffffffff8021358d>] __do_page_cache_readahead+0x17b/0x1fc
 [<ffffffff80234e37>] blockable_page_cache_readahead+0x5f/0xc1
 [<ffffffff80214784>] page_cache_readahead+0x146/0x1bb
 [<ffffffff8020c2d6>] do_generic_mapping_read+0x157/0x4b4
 [<ffffffff8020c78e>] __generic_file_aio_read+0x15b/0x1b1
 [<ffffffff802c852e>] generic_file_read+0xc6/0xe0
 [<ffffffff8020b5fb>] vfs_read+0xcc/0x172
 [<ffffffff802121ae>] sys_read+0x47/0x6f
 [<ffffffff802603ce>] system_call+0x7e/0x83
DWARF2 unwinder stuck at system_call+0x7e/0x83

Leftover inexact backtrace:



Chris Chabot wrote:
> Hi Guys,
>
> I was wondering if someone was going thru the same dmraid 'challenges' 
> as me and had figured out a solution to boot the recent (-25xx) 
> kernels, since i now seem to be unable too (again)
>
> First some historical background.. I've gotten a Dell XPS600 system 
> about 6 months ago, it comes with all kinds of goodnesses, including 
> 2x250gb serial ata disks in 'hardware assisted' raid0 mode, 
> specifically with a a nVidia Intel SLI motherboard and its "nVidia 
> Corporation CK804" serial ata controller / raid.
>
> Before Fedora Core 4.9x, it was impossible to run linux on this 
> machine since the raid set was not supported but then in the Fedora 
> Core 4.9x (fc5 test 1 and 2) releases it worked just fine .. no 
> sweat.. insert cd, sometimes fiddle with configs a little bit, and i 
> was up and running! Also FC5 seemed to work great out of the box (2054 
> kernel), sometimes i hit some great glitches of not booting because of 
> the 'dm-striped device sizes must be a multiple of chunk-size for 
> 2.6.16 kernels' bug (well some call it a feature :-)), for a while i 
> was forced to run older kernels until i figured out how to fix it thru 
> some magical dmsetup and friends commands
>
> Then came FC5 updates, and the updated kernels didn't work on my 
> dmraid set .. Turned out some of my problems were caused by the init 
> script in the initrd images, which wasn't adding the 'dmraid setup' 
> commands, ergo no root disks, no linux :-)
>
> And for a while now, all the way upto the 2.6.17 24xx kernels, i've 
> been able to update my kernels by gunzipping / cpio'ing / editing the 
> init script / packaging it back up into a new initrd.img file ..
>
> However since a week or so (maybe 2 ? i'm not sure), this trick didn't 
> work anymore .. the good news was that the dmraid setup commands were 
> now automaticly included in the init script again, however despite 
> their presence at boot i am now supprised by no error reports, until 
> the 'could not mount the root device' comes up and tells me that this 
> attempt was an utter failure.
>
> I've diffed the init scripts from my working booting kernel (which is 
> 2.6.17-1.2364 for some obscure historical but unknown to me reason) 
> and the one in 2517, and there were no differences, so everything 
> should work right! :-)
>
> Anyone been having the same problems and been able to figure out what 
> now is making booting impossible? I'd be positively delighted to learn 
> how to fix it again :-)
>
> Kindest Regards,
>
>    -- Chris Chabot
>