What is in include/linux/kernel.h line 158

[Antonio Olivares]

----- Original Message ----
From: Matt Domsch <Matt_Domsch at dell.com>
To: Community support for Fedora users <users at lists.fedoraproject.org>
Sent: Mon, April 12, 2010 1:28:37 PM
Subject: Re: What is in include/linux/kernel.h line 158

On Sat, Apr 10, 2010 at 01:29:08PM -0700, Antonio Olivares wrote:
> Dear folks, 
> 
> I have encountered this so called sleeping function several times in a good while (kernel 2.6.27, 2.6.29, 2.6.30, 2.6.31, 2.6.32) Fedora based kernels and compiled kernels from kernel.org, 
> 
> I am asking this because I see this again and again.  I would like to know what is in there so if I can do something about it, or just live with it since it appears to be harmless, but anyhow it is annoying :(  
> 
> BUG: sleeping function called from invalid context at include/linux/kernel.h:158
> in_atomic(): 0, irqs_disabled(): 1, pid: 9713, name: slmodemd
> Pid: 9713, comm: slmodemd Tainted: P          2.6.32.10-90.fc12.i686.PAE #1
> Call Trace:
>  [<c043372f>] __might_sleep+0xca/0xd1
>  [<c05c6c3a>] might_fault+0x19/0x20
>  [<c05c6d8e>] copy_to_user+0x34/0x10a
>  [<fe2b32ca>] amrmo_read+0x50/0x66 [slamr]
>  [<fe2b327a>] ? amrmo_read+0x0/0x66 [slamr]
>  [<c04e15fc>] vfs_read+0x82/0xe1
>  [<c04e9d17>] ? path_put+0x1a/0x1d
>  [<c04e16f9>] sys_read+0x40/0x62
>  [<c040907b>] sysenter_do_call+0x12/0x28

The source code to the slamr module (amrmo_read() function) is not
present in Fedora or kernel.org.  The BUG message is complaining that
something (the amrmo_read() function) has disabled interrupts (the
irqs_disabled(): 1 part of the message), while at the same time
calling a function (copy_to_user()) which can sleep (the process could
be unscheduled or mapped out at the moment copy_to_user() is called),
so you could wind up deadlocked (interrupts off so nothing to wake the
scheduler back up).

This is a bug in the slamr driver.

Thanks,
Matt

-- 
Matt Domsch
Technology Strategist
Dell | Office of the CTO
-- 


Thank you Matt.  Yair from linmodems.org mailing list explained it carefully.  I guess there is no choice but to live with it :(  
Smartlink no longer makes modems, but is still closed source, can't win them all :(

Regards,

Antonio