[PATCH] powerpc/powernv: delay rng of node creation until later in boot

[Jason A. Donenfeld]

Hi Michael,

On Mon, Jul 04, 2022 at 09:14:32PM +1000, Michael Ellerman wrote:
> 
> 
> On 2 July 2022 8:42:06 pm AEST, "Jason A. Donenfeld" <Jason at zx2c4.com> wrote:
> >Hi Benjamin, Paul,
> >
> >On Thu, Jun 30, 2022 at 07:24:05PM +0530, Sachin Sant wrote:
> >> > On 30-Jun-2022, at 5:46 PM, Jason A. Donenfeld <Jason at zx2c4.com> wrote:
> >> > 
> >> > The of node for the rng must be created much later in boot. Otherwise it
> >> > tries to connect to a parent that doesn't yet exist, resulting on this
> >> > splat:
> >> > 
> >> > [    0.000478] kobject: '(null)' ((____ptrval____)): is not initialized, yet kobject_get() is being called.
> >> > [    0.002925] [c000000002a0fb30] [c00000000073b0bc] kobject_get+0x8c/0x100 (unreliable)
> >> > [    0.003071] [c000000002a0fba0] [c00000000087e464] device_add+0xf4/0xb00
> >> > [    0.003194] [c000000002a0fc80] [c000000000a7f6e4] of_device_add+0x64/0x80
> >> > [    0.003321] [c000000002a0fcb0] [c000000000a800d0] of_platform_device_create_pdata+0xd0/0x1b0
> >> > [    0.003476] [c000000002a0fd00] [c00000000201fa44] pnv_get_random_long_early+0x240/0x2e4
> >> > [    0.003623] [c000000002a0fe20] [c000000002060c38] random_init+0xc0/0x214
> >> > 
> >> > This patch fixes the issue by doing the of node creation inside of
> >> > machine_subsys_initcall.
> >> > 
> >> > Fixes: f3eac426657d ("powerpc/powernv: wire up rng during setup_arch")
> >> > Cc: stable at vger.kernel.org
> >> > Cc: Michael Ellerman <mpe at ellerman.id.au>
> >> > Reported-by: Sachin Sant <sachinp at linux.ibm.com>
> >> > Signed-off-by: Jason A. Donenfeld <Jason at zx2c4.com>
> >> > ---
> >> 
> >> Thanks Jason for the patch. This fixes the reported problem for me.
> >> 
> >> Tested-by: Sachin Sant <sachinp at linux.ibm.com>
> >> 
> >> - Sachin
> >
> >It sounds like Michael is on vacation for a few weeks. Think you could
> >queue this up so we can get POWER8 booting again?
> 
> It doesn't break booting for me, but it is an ugly splat.
> 
> I'll pick it up into fixes.
> 
> I think it's more correct to say the "platform device creation" causes the problem, so I'll update the change log to say that.

Sounds good. Thank you!

Jason