[next-20210820][ppc][nvme/raid] pci unbind WARNS at fs/kernfs/dir.c:1524 kernfs_remove_by_name_ns+

[Abdul Haleem]

Greeting's

Today's linux-next kernel WARN's while unbind of pci ssd flash device on 
my powerpc box

# lspci -nn
001d:80:00.0 Non-Volatile memory controller [0108]: Seagate Technology 
PLC Nytro Flash Storage [1bb1:0100]
001e:90:00.0 Non-Volatile memory controller [0108]: Seagate Technology 
PLC Nytro Flash Storage [1bb1:0100]

$ echo -n 001d:80:00.0 > /sys/bus/pci/drivers/nvme/unbind

md: md127: raid0 array has a missing/failed member
Buffer I/O error on dev md127, logical block 1498959, async page read
Buffer I/O error on dev md127, logical block 1498959, async page read
md127: detected capacity change from 191866880 to 0
md: md127 stopped.
------------[ cut here ]------------
kernfs: can not remove 'md127', no directory
WARNING: CPU: 21 PID: 11006 at fs/kernfs/dir.c:1524 
kernfs_remove_by_name_ns+0xc0/0x110

Modules linked in: dm_mod rpadlpar_io rpaphp kvm_pr kvm nf_tables 
libcrc32c nfnetlink tcp_diag udp_diag inet_diag unix_diag af_packet_diag 
netlink_diag bridge stp llc rfkill sg pseries_rng raid0 xts vmx_crypto 
uio_pdrv_genirq gf128mul uio nfsd auth_rpcgss nfs_acl lockd grace sunrpc 
binfmt_misc sch_fq_codel ip_tables ext4 mbcache jbd2 sd_mod ibmvscsi 
ibmvnic ibmveth scsi_transport_srp nvme nvme_core t10_piCPU: 21 PID: 
11006 Comm: mdadm Not tainted 5.14.0-rc6-next-20210820-autotest #1

NIP:  c00000000056dda0 LR: c00000000056dd9c CTR: 00000000007088ec
REGS: c000000004593680 TRAP: 0700   Not tainted 
(5.14.0-rc6-next-20210820-autotest)
MSR:  800000000282b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE>  CR: 48044224  
XER: 0000000d
CFAR: c000000000145f00 IRQMASK: 0
GPR00: c00000000056dd9c c000000004593920 c0000000019b3200 000000000000002c
GPR04: 00000000ffff7fff c0000000045935f0 0000000000000027 c00000077cd07e08
GPR08: 0000000000000023 0000000000000001 0000000000000027 c0000000018694b0
GPR12: 0000000000004000 c00000001ec40680 00007fff84875040 ffffffffffffffff
GPR16: 0000000000000000 0000000000000001 0000000000000000 000001001e990280
GPR20: 0000000000000000 0000000000000000 0000000000000066 0000000000030d40
GPR24: c00000002bc591e8 0000000000000000 c00000002bc591c8 c000000025765c00
GPR28: c000000025765c70 c000000025765c00 0000000000000000 c000000025790640
NIP [c00000000056dda0] kernfs_remove_by_name_ns+0xc0/0x110
LR [c00000000056dd9c] kernfs_remove_by_name_ns+0xbc/0x110
Call Trace:
[c000000004593920] [c00000000056dd9c] 
kernfs_remove_by_name_ns+0xbc/0x110 (unreliable)
[c0000000045939b0] [c000000000572368] sysfs_remove_link+0x28/0x70
[c0000000045939d0] [c000000000678bd4] bd_unlink_disk_holder+0xc4/0x130
[c000000004593a10] [c00000000098e4e0] unbind_rdev_from_array+0x40/0x1b0
[c000000004593ac0] [c0000000009921e0] do_md_stop+0x410/0x5a0
[c000000004593bc0] [c0000000009966ac] md_ioctl+0xc6c/0x1c60
[c000000004593cd0] [c000000000654ebc] blkdev_ioctl+0x2fc/0x740
[c000000004593d40] [c0000000004ce284] block_ioctl+0x74/0x90
[c000000004593d60] [c00000000047b6e8] sys_ioctl+0xf8/0x150
[c000000004593db0] [c00000000002ff28] system_call_exception+0x158/0x2c0
[c000000004593e10] [c00000000000c764] system_call_common+0xf4/0x258
--- interrupt: c00 at 0x7fff84790290
NIP:  00007fff84790290 LR: 000000013d5c2ef0 CTR: 0000000000000000
REGS: c000000004593e80 TRAP: 0c00   Not tainted 
(5.14.0-rc6-next-20210820-autotest)
MSR:  800000000280f033 <SF,VEC,VSX,EE,PR,FP,ME,IR,DR,RI,LE>  CR: 
28044288  XER: 00000000
IRQMASK: 0
GPR00: 0000000000000036 00007fffd0148020 00007fff84877300 0000000000000003
GPR04: 0000000020000932 0000000000000000 0000000000030d40 00007fffd0148028
GPR08: 0000000000000003 0000000000000000 0000000000000000 0000000000000000
GPR12: 0000000000000000 00007fff8494a780 00007fff84875040 ffffffffffffffff
GPR16: 0000000000000000 0000000000000001 0000000000000000 000001001e990280
GPR20: 0000000000000000 0000000000000000 0000000000000066 0000000000030d40
GPR24: 0000000020000932 000001001e992ac0 ffffffffffffffff 000001001e990a40
GPR28: ffffffffffffffff 0000000000000018 00007fffd0148100 0000000000000003
NIP [00007fff84790290] 0x7fff84790290
LR [000000013d5c2ef0] 0x13d5c2ef0
--- interrupt: c00
Instruction dump:
ebe10088 38210090 e8010010 ebc1fff0 7c0803a6 4e800020 60000000 60000000
3c62ff5c 3863d168 4bbd8109 60000000 <0fe00000> fba10078 fbe10088 60000000
---[ end trace 634fa04d6dac7dfd ]---

-- 
Regard's

Abdul Haleem
IBM Linux Technology Center