Subject: Re: powerpc/powernv: Fix missing attr initialisation in opal_export_attrs()

From: Michael Ellerman <[email-masked]>
Date: Thu, 27 Apr 2017 20:30:58 +1000 (AEST)

On Thu, 2017-04-27 at 01:37:32 UTC, Michael Ellerman wrote:
> In opal_export_attrs() we dynamically allocate some bin_attributes. They're
> allocated with kmalloc() and although we initialise most of the fields, we don't
> initialise write() or mmap(), and in particular we don't initialise the lockdep
> related fields in the embedded struct attribute.
> 
> This leads to a lockdep warning at boot:
> 
>   BUG: key c0000000f11906d8 not in .data!
>   WARNING: CPU: 0 PID: 1 at ../kernel/locking/lockdep.c:3136 lockdep_init_map+0x28c/0x2a0
>   ...
>   Call Trace:
>     lockdep_init_map+0x288/0x2a0 (unreliable)
>     __kernfs_create_file+0x8c/0x170
>     sysfs_add_file_mode_ns+0xc8/0x240
>     __machine_initcall_powernv_opal_init+0x60c/0x684
>     do_one_initcall+0x60/0x1c0
>     kernel_init_freeable+0x2f4/0x3d4
>     kernel_init+0x24/0x160
>     ret_from_kernel_thread+0x5c/0xb0
> 
> Fix it by kzalloc'ing the attr, which fixes the uninitialised write() and
> mmap(), and calling sysfs_bin_attr_init() on it to initialise the lockdep
> fields.
> 
> Fixes: 11fe909d2362 ("powerpc/powernv: Add OPAL exports attributes to sysfs")
> Signed-off-by: Michael Ellerman <[email-masked]>

Applied to powerpc next.

https://git.kernel.org/powerpc/c/83c4919058459c32138a1ebe35f72b

cheers