Re: lockdep: BUG: key ffff880436f00330 not in .data!

[Borislav Petkov]

On Thu, May 09, 2013 at 10:01:08PM +0200, Borislav Petkov wrote:
> On Thu, May 09, 2013 at 11:28:08AM -0300, Mauro Carvalho Chehab wrote:
> > Could you please check if ghes_edac also got registered there?

Ok, I got it:

[    5.430408] BUG: key ffff88043c320330 not in .data!
[    5.431043] ------------[ cut here ]------------
[    5.431776] WARNING: at kernel/lockdep.c:2987 lockdep_init_map+0x555/0x590()
[    5.432512] DEBUG_LOCKS_WARN_ON(1)

basically means we're using dynamically allocated memory for the
lock_key. And the last can thus disappear, which is Not Good(tm).

This happens because the EDAC instance probing functions do
edac_mc_alloc() to allocate the mci which also contains embedded in it:

	struct bus_type                 bus;

and the bus_register() call in edac_create_sysfs_mci_device() hands down
this struct bus_type to lockdep.

The patch which introduced the bus_register() call in
edac_create_sysfs_mci_device() is

--
commit de3910eb79ac8c0f29a11224661c0ebaaf813039
Author: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Date:   Tue Apr 24 15:05:43 2012 -0300

    edac: change the mem allocation scheme to make Documentation/kobject.txt happy
--

which means we need a fix since this affects all edac drivers, not only
sb_edac, as initially surmised.

Thanks.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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