Floppy constantly accessed in 2.6.31-rc2

Floppy constantly accessed in 2.6.31-rc2

[Robert Hancock]

On 2.6.31-rc2 (actually current git as of today) the floppy drive is 
constantly being accessed with these messages being reported:

Platform driver 'floppy' needs updating - please use dev_pm_ops
Floppy drive(s): fd0 is 1.44M
FDC 0 is a post-1991 82077
end_request: I/O error, dev fd0, sector 0
end_request: I/O error, dev fd0, sector 0
end_request: I/O error, dev fd0, sector 0
end_request: I/O error, dev fd0, sector 0
end_request: I/O error, dev fd0, sector 0
end_request: I/O error, dev fd0, sector 0
end_request: I/O error, dev fd0, sector 0

lsof reports no process with /dev/fd0 open so it is not clear what is 
causing this activity. It looks like the access starts when I log in to 
X, but doesn't stop when I log out. I'm guessing HAL or something checks 
the floppy drive and then the kernel somehow gets stuck in a loop 
retrying the request..

Anyone have any ideas what might be causing this? Commit 
5e50b9ef975219304cc91d601530994861585bfe seemed a bit suspicious but 
reverting it didn't seem to help. (It did get rid of the dev_pm_ops 
message, though..)

Re: Floppy constantly accessed in 2.6.31-rc2

[Andrew Morton]

On Sun, 12 Jul 2009 23:44:19 -0600
Robert Hancock <hancockrwd@gmail.com> wrote:

> On 2.6.31-rc2 (actually current git as of today) the floppy drive is 
> constantly being accessed with these messages being reported:
> 
> Platform driver 'floppy' needs updating - please use dev_pm_ops
> Floppy drive(s): fd0 is 1.44M
> FDC 0 is a post-1991 82077
> end_request: I/O error, dev fd0, sector 0
> end_request: I/O error, dev fd0, sector 0
> end_request: I/O error, dev fd0, sector 0
> end_request: I/O error, dev fd0, sector 0
> end_request: I/O error, dev fd0, sector 0
> end_request: I/O error, dev fd0, sector 0
> end_request: I/O error, dev fd0, sector 0
> 
> lsof reports no process with /dev/fd0 open so it is not clear what is 
> causing this activity. It looks like the access starts when I log in to 
> X, but doesn't stop when I log out. I'm guessing HAL or something checks 
> the floppy drive and then the kernel somehow gets stuck in a loop 
> retrying the request..
> 
> Anyone have any ideas what might be causing this? Commit 
> 5e50b9ef975219304cc91d601530994861585bfe seemed a bit suspicious but 
> reverting it didn't seem to help. (It did get rid of the dev_pm_ops 
> message, though..)

I'd suggest doing something like this:

--- a/drivers/block/floppy.c~a
+++ a/drivers/block/floppy.c
@@ -2975,6 +2975,7 @@ static struct cont_t rw_cont = {
 
 static void process_fd_request(void)
 {
+	dump_stack();
 	cont = &rw_cont;
 	schedule_bh(redo_fd_request);
 }
_

to find out who is poking the floppy.

If you're correct and some process is stuck doing infinite retries then
that process should be visible in the `ps' output, probably stuck in D
state.  Please have a look, see if you can work out which process is
hitting the problem and gather its kernel stack backtrace, thanks.

Meanwhile I'll ask Rafael to add this to the regression list.

Re: Floppy constantly accessed in 2.6.31-rc2

[Paul Bolle]

On Sun, 2009-07-12 at 23:44 -0600, Robert Hancock wrote:
> On 2.6.31-rc2 (actually current git as of today) the floppy drive is 
> constantly being accessed with these messages being reported:
> 
> Platform driver 'floppy' needs updating - please use dev_pm_ops
> Floppy drive(s): fd0 is 1.44M
> FDC 0 is a post-1991 82077
> end_request: I/O error, dev fd0, sector 0
> end_request: I/O error, dev fd0, sector 0
> end_request: I/O error, dev fd0, sector 0
> end_request: I/O error, dev fd0, sector 0
> end_request: I/O error, dev fd0, sector 0
> end_request: I/O error, dev fd0, sector 0
> end_request: I/O error, dev fd0, sector 0
> 
> lsof reports no process with /dev/fd0 open so it is not clear what is 
> causing this activity. It looks like the access starts when I log in to 
> X, but doesn't stop when I log out. I'm guessing HAL or something checks 
> the floppy drive and then the kernel somehow gets stuck in a loop 
> retrying the request..

That does look a bit like
https://bugzilla.redhat.com/show_bug.cgi?id=489083 (and its duplicate
https://bugzilla.redhat.com/show_bug.cgi?id=496586 ).

Regards,


Paul Bolle

Re: Floppy constantly accessed in 2.6.31-rc2

[Robert Hancock]

On 07/13/2009 05:06 PM, Paul Bolle wrote:
> On Sun, 2009-07-12 at 23:44 -0600, Robert Hancock wrote:
>> On 2.6.31-rc2 (actually current git as of today) the floppy drive is
>> constantly being accessed with these messages being reported:
>>
>> Platform driver 'floppy' needs updating - please use dev_pm_ops
>> Floppy drive(s): fd0 is 1.44M
>> FDC 0 is a post-1991 82077
>> end_request: I/O error, dev fd0, sector 0
>> end_request: I/O error, dev fd0, sector 0
>> end_request: I/O error, dev fd0, sector 0
>> end_request: I/O error, dev fd0, sector 0
>> end_request: I/O error, dev fd0, sector 0
>> end_request: I/O error, dev fd0, sector 0
>> end_request: I/O error, dev fd0, sector 0
>>
>> lsof reports no process with /dev/fd0 open so it is not clear what is
>> causing this activity. It looks like the access starts when I log in to
>> X, but doesn't stop when I log out. I'm guessing HAL or something checks
>> the floppy drive and then the kernel somehow gets stuck in a loop
>> retrying the request..
>
> That does look a bit like
> https://bugzilla.redhat.com/show_bug.cgi?id=489083 (and its duplicate
> https://bugzilla.redhat.com/show_bug.cgi?id=496586 ).

Indeed, it is.. It looks like in 2.6.29.5 the floppy module isn't being 
autoloaded and in 2.6.31-rc2 it is, which causes the DeviceKit bug to 
show up. Updating DeviceKit seems to fix the problem.

So, not a kernel regression.