This is a note to let you know that I've just added the patch titled powerpc/powernv: delay rng platform device creation until later in boot to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-powernv-delay-rng-platform-device-creation-until-later-in-boot.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 887502826549caa7e4215fd9e628f48f14c0825a Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" <Jason@xxxxxxxxx> Date: Thu, 30 Jun 2022 14:16:54 +0200 Subject: powerpc/powernv: delay rng platform device creation until later in boot From: Jason A. Donenfeld <Jason@xxxxxxxxx> 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@xxxxxxxxxxxxxxx Reported-by: Sachin Sant <sachinp@xxxxxxxxxxxxx> Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx> Tested-by: Sachin Sant <sachinp@xxxxxxxxxxxxx> [mpe: Change "of node" to "platform device" in change log] Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220630121654.1939181-1-Jason@xxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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); Patches currently in stable-queue which might be from Jason@xxxxxxxxx are queue-4.14/powerpc-powernv-delay-rng-platform-device-creation-until-later-in-boot.patch