lockdep WARN_ON in ppc440 with -next

[Joel Stanley]

Hello,

I was booting next-20181213 in qemu with lockdep enabled and saw this:

spin_lock-torture:--- Start of test [debug]: nwriters_stress=2
nreaders_stress=0 stat_interval=60 verbose=1 shuffle_interval=3
stutter=5 shutdown_secs=0 onoff_interval=0 onoff_holdoff=0
spin_lock-torture: Creating torture_shuffle task
spin_lock-torture: Creating torture_stutter task
spin_lock-torture: torture_shuffle task started
spin_lock-torture: Creating lock_torture_writer task
spin_lock-torture: torture_stutter task started
spin_lock-torture: Creating lock_torture_writer task
spin_lock-torture: lock_torture_writer task started
spin_lock-torture: Creating lock_torture_stats task
spin_lock-torture: lock_torture_writer task started
spin_lock-torture: lock_torture_stats task started
torture_init_begin: Refusing rcu init: spin_lock running.
torture_init_begin: One torture test at a time!
workingset: timestamp_bits=30 max_order=15 bucket_order=0
jffs2: version 2.2. (NAND) © 2001-2006 Red Hat, Inc.
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)
WARNING: CPU: 0 PID: 379 at kernel/locking/lockdep.c:3765
check_flags+0x230/0x248
Modules linked in:
CPU: 0 PID: 379 Comm: modprobe Not tainted 4.20.0-rc6-next-20181213-dirty #1
NIP:  c007c7a4 LR: c007c7a4 CTR: 00000000
REGS: c7b95de0 TRAP: 0700   Not tainted  (4.20.0-rc6-next-20181213-dirty)
MSR:  00021000 <CE,ME>  CR: 22000c22  XER: 20000000

GPR00: c007c7a4 c7b95e90 c7b9a580 0000002f 00000000 00000001 c0fed2d6 c0fed2d7
GPR08: 00000000 21637572 c0f741df 00000004 22000c22 100d803e 00000000 00000000
GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
GPR24: c7b94000 00000000 00000000 00000000 c0860f98 ffffffff 00029000 10003d38
NIP [c007c7a4] check_flags+0x230/0x248
LR [c007c7a4] check_flags+0x230/0x248
Call Trace:
[c7b95e90] [c007c7a4] check_flags+0x230/0x248 (unreliable)
[c7b95ea0] [c007f430] lock_is_held_type+0x4c/0x114
[c7b95ed0] [c066801c] __schedule+0x84/0x934
[c7b95f30] [c066893c] schedule+0x70/0x9c
[c7b95f40] [c000f928] recheck+0x0/0x24
--- interrupt: 901 at 0xb7bdbe18
    LR = 0xb7b6da7c
Instruction dump:
3c80c08d 2c030000 8084e69c 2c840000 4e823342 41940020 3c60c076 3c80c076
4cc63182 3863c724 38840cf8 4bfbdd1d <0fe00000> 3c60c076 38630d13 4cc63182
irq event stamp: 428
hardirqs last  enabled at (426): [<c066dbf8>] _raw_spin_unlock_irq+0x30/0x58
hardirqs last disabled at (427): [<c066e8a4>] __do_softirq+0x394/0x52c
softirqs last  enabled at (428): [<c003ecc4>] irq_exit+0xdc/0x100
softirqs last disabled at (419): [<c003ecc4>] irq_exit+0xdc/0x100
---[ end trace 3f1ce6c3406f3dee ]---
possible reason: unannotated irqs-on.
irq event stamp: 428
hardirqs last  enabled at (426): [<c066dbf8>] _raw_spin_unlock_irq+0x30/0x58
hardirqs last disabled at (427): [<c066e8a4>] __do_softirq+0x394/0x52c
softirqs last  enabled at (428): [<c003ecc4>] irq_exit+0xdc/0x100
softirqs last disabled at (419): [<c003ecc4>] irq_exit+0xdc/0x100
Block layer SCSI generic (bsg) driver version 0.4 loaded (major 253)
io scheduler mq-deadline registered
io scheduler kyber registered

I am running ppc44x_defconfig under qemu with the bamboo machine:

qemu-system-ppc -m 128m -machine bamboo -dtb
arch/powerpc/boot/dts/bamboo.dtb -append console=ttyS0 -initrd
images/ppc32/rootfs.cpio -nographic -kernel
linux-next/arch/powerpc/boot/zImage