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

[Michael Ellerman]

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.

cheers