[-merge] BUG followed by oops running ndctl tests

[Sachin Sant]

Following Oops is seen on latest (commit 3b4852888d) powerpc merge branch
code while running ndctl (test_namespace) tests

85c5b0984e was good.

 (06/12) avocado-misc-tests/memory/ndctl.py:NdctlTest.test_namespace:  [  213.570536] memmap_init_zone_device initialised 1636608 pages in 10ms
[  213.570835] pmem0: detected capacity change from 0 to 107256741888
[  216.488983] BUG: Unable to handle kernel data access at 0xc000043900000000
[  216.488996] Faulting instruction address: 0xc000000000087510
[  216.489002] Oops: Kernel access of bad area, sig: 11 [#1]
[  216.489007] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
[  216.489019] Dumping ftrace buffer:
[  216.489029]    (ftrace buffer empty)
[  216.489033] Modules linked in: dm_mod nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c ip6_tables nft_compat ip_set nf_tables nfnetlink sunrpc sg pseries_rng papr_scm uio_pdrv_genirq uio sch_fq_codel ip_tables sd_mod ibmvscsi ibmveth scsi_transport_srp
[  216.489059] CPU: 8 PID: 17523 Comm: lt-ndctl Not tainted 5.4.0-rc7-autotest #1
[  216.489065] NIP:  c000000000087510 LR: c00000000008752c CTR: 01ffffffce800000
[  216.489071] REGS: c000007ca84a37d0 TRAP: 0300   Not tainted  (5.4.0-rc7-autotest)
[  216.489076] MSR:  800000000280b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE>  CR: 42048224  XER: 00000000
[  216.489086] CFAR: c000000000087518 DAR: c000043900000000 DSISR: 40000000 IRQMASK: 0 
[  216.489086] GPR00: c00000000008752c c000007ca84a3a60 c00000000159bb00 0000000000000000 
[  216.489086] GPR04: 40066bdea7010e15 0000605530000194 0000000000000000 0000000000000080 
[  216.489086] GPR08: c000043900000000 ffffffffc000007f 01ffffffff800000 0000000000000000 
[  216.489086] GPR12: 0000000000008000 c00000001ec5d200 00007ffff897f9e9 000000001002e088 
[  216.489086] GPR16: 0000000000000000 0000000010050d88 000000001002f778 000000001002f770 
[  216.489086] GPR20: 0000000000000000 000000001002e048 0000000010050e3d 0000000010050e40 
[  216.489086] GPR24: 0000000000000000 c000007c8d0a6c10 c000007cced28a20 c000000001463048 
[  216.489086] GPR28: c000042080000000 c000042040000000 c000043900000000 c000042000000000 
[  216.489137] NIP [c000000000087510] arch_remove_memory+0x100/0x1b0
[  216.489143] LR [c00000000008752c] arch_remove_memory+0x11c/0x1b0
[  216.489148] Call Trace:
[  216.489151] [c000007ca84a3a60] [c00000000008752c] arch_remove_memory+0x11c/0x1b0 (unreliable)
[  216.489159] [c000007ca84a3b00] [c000000000407258] memunmap_pages+0x188/0x2c0
[  216.489167] [c000007ca84a3b80] [c0000000007b0810] devm_action_release+0x30/0x50
[  216.489174] [c000007ca84a3ba0] [c0000000007b18f8] release_nodes+0x2f8/0x3e0
[  216.489180] [c000007ca84a3c50] [c0000000007aa698] device_release_driver_internal+0x168/0x270
[  216.489187] [c000007ca84a3c90] [c0000000007a6ad0] unbind_store+0x130/0x170
[  216.489193] [c000007ca84a3cd0] [c0000000007a5c34] drv_attr_store+0x44/0x60
[  216.489200] [c000007ca84a3cf0] [c0000000004fa0d8] sysfs_kf_write+0x68/0x80
[  216.489205] [c000007ca84a3d10] [c0000000004f9530] kernfs_fop_write+0xf0/0x270
[  216.489212] [c000007ca84a3d60] [c00000000040cbdc] __vfs_write+0x3c/0x70
[  216.489217] [c000007ca84a3d80] [c00000000041052c] vfs_write+0xcc/0x240
[  216.489223] [c000007ca84a3dd0] [c00000000041090c] ksys_write+0x7c/0x140
[  216.489229] [c000007ca84a3e20] [c00000000000b278] system_call+0x5c/0x68
[  216.489233] Instruction dump:
[  216.489238] 80fb0008 815b000c 7d0700d0 7d08e038 7c0004ac 4c00012c 3927ffff 7d29ea14 
[  216.489245] 7d284850 7d2a5437 41820014 7d4903a6 <7c0040ac> 7d083a14 4200fff8 7c0004ac 
[  216.489254] ---[ end trace d9a4dfc9e158858a ]—

Thanks
-Sachin