[PATCH 5.15 166/230] powerpc/powernv: delay rng platform device creation until later in boot

Greg Kroah-Hartman
2022-07-11T09:57:41Z

From: Jason A. Donenfeld <Jason@zx2c4.com>

commit 887502826549caa7e4215fd9e628f48f14c0825a upstream.

The platform device for the rng must be created much later in boot.
Otherwise it tries to connect to a parent that doesn't yet exist,
resulting in 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 platform device creation inside
of machine_subsys_initcall.

Fixes: f3eac426657d ("powerpc/powernv: wire up rng during setup_arch")
Cc: stable@vger.kernel.org
Reported-by: Sachin Sant <sachinp@linux.ibm.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Tested-by: Sachin Sant <sachinp@linux.ibm.com>
[mpe: Change "of node" to "platform device" in change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220630121654.1939181-1-Jason@zx2c4.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/powerpc/platforms/powernv/rng.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)

--- a/arch/powerpc/platforms/powernv/rng.c
+++ b/arch/powerpc/platforms/powernv/rng.c
@@ -176,12 +176,8 @@ static int __init pnv_get_random_long_ea
NULL) != pnv_get_random_long_early)
return 0;

- for_each_compatible_node(dn, NULL, "ibm,power-rng") {
- if (rng_create(dn))
- continue;
- /* Create devices for hwrng driver */
- of_platform_device_create(dn, NULL, NULL);
- }
+ for_each_compatible_node(dn, NULL, "ibm,power-rng")
+ rng_create(dn);

if (!ppc_md.get_random_seed)
return 0;
@@ -205,10 +201,18 @@ void __init pnv_rng_init(void)

static int __init pnv_rng_late_init(void)
{
+ struct device_node *dn;
unsigned long v;
+
/* In case it wasn't called during init for some other reason. */
if (ppc_md.get_random_seed == pnv_get_random_long_early)
pnv_get_random_long_early(&v);
+
+ if (ppc_md.get_random_seed == powernv_get_random_long) {
+ for_each_compatible_node(dn, NULL, "ibm,power-rng")
+ of_platform_device_create(dn, NULL, NULL);
+ }
+
return 0;
}
machine_subsys_initcall(powernv, pnv_rng_late_init);