[BUG 4.9] New led trigger usbport gets the kernel to panic

[Ralph Sennhauser]

Hi RafaÅ,

I tried your new usbport trigger in Linux 4.9 with little luck as can be seen in
the following output of the serial console.

  root@wrt1900acs:/# cd /sys/class/leds/pca963x\:shelby\:white\:usb2/
  root@wrt1900acs:/sys/devices/platform/soc/soc:internal-regs/f1011000.i2c/i2c-0/0-0068/leds/pca963x:shelby:white:usb2# echo usbport > trigger
  root@wrt1900acs:/sys/devices/platform/soc/soc:internal-regs/f1011000.i2c/i2c-0/0-0068/leds/pca963x:shelby:white:usb2# echo 1 > ports/usb2-port1
  [ 1461.761528] Unable to handle kernel NULL pointer dereference at virtual address 00000000
  [ 1461.769734] pgd = de33c000
  [ 1461.772454] [00000000] *pgd=1cb2a831, *pte=00000000, *ppte=00000000
  [ 1461.778791] Internal error: Oops: 80000007 [#1] SMP ARM
  [ 1461.784036] Modules linked in: iptable_nat nft_chain_nat_ipv4 nf_tables_inet
  nf_nat_ipv4 nf_conntrack_ipv6 nf_conntrack_ipv4 ipt_REJECT ipt_MASQUERADE
  xt_time xt_tcpudp xt_state xt_nat xt_multiport xt_mark xt_mac xt_limit
  xt_conntrack xt_comment xt_TCP MSS xt_REDIRECT xt_LOG xt_CT nft_set_rbtree
  nft_set_hash nft_reject_inet nft_reject nft_redir_ipv4 nft_redir nft_nat
  nft_meta nft_masq_ipv4 nft_masq nft_log nft_limit nft_hash nft_exthdr nft_ct
  nft_counter nft_chain_route_ipv6 nft_chain_route_ipv4 nf_tabl es_ipv6
  nf_tables_ipv4 nf_tables nf_reject_ipv4 nf_nat_redirect nf_nat_masquerade_ipv4
  nf_nat nf_log_ipv4 nf_defrag_ipv6 nf_defrag_ipv4 nf_conntrack_netlink
  nf_conntrack macvlan libcrc32c iptable_raw iptable_mangle iptable_filter
  ip_tables act_skbedit act _mirred em_u32 cls_u32 cls_tcindex cls_flow cls_route
  cls_fw sch_hfsc sch_ingress mwlwifi(O) mac80211 cfg80211 ledtrig_netdev(O)
  ip_set_list_set ip_set_hash_netiface ip_set_hash_netport ip_set_hash_netnet
  ip_set_hash_net ip_set_hash_netportnet ip_set_hash _mac ip_set_hash_ipportnet
  ip_set_hash_ipportip ip_set_hash_ipport ip_set_hash_ipmark ip_set_hash_ip
  ip_set_bitmap_port ip_set_bitmap_ipmac ip_set_bitmap_ip ip_set nfnetlink
  ip6t_REJECT nf_reject_ipv6 nf_log_ipv6 nf_log_common ip6table_raw
  ip6table_mangle ip6table_filter ip6_tables x_tables ifb sit tunnel4 ip_tunnel
  vfat fat nls_utf8 nls_iso8859_1 nls_cp850 nls_cp437 rfkill input_core
  sha256_generic seqiv jitterentropy_rng drbg hmac ghash_generic gf128mul gcm ctr
  ccm ledtrig_usbport ext4 jbd2 mbcache btrf s xor raid6_pq crc32c_generic ubifs
  ubi
  [ 1461.922401] CPU: 0 PID: 759 Comm: ash Tainted: G           O    4.9.0-rc6 #2
  [ 1461.929476] Hardware name: Marvell Armada 380/385 (Device Tree)
  [ 1461.935418] task: df621080 task.stack: dee0e000
  [ 1461.939966] PC is at 0x0
  [ 1461.942510] LR is at usbport_trig_port_store+0x8c/0xd8 [ledtrig_usbport]
  [ 1461.949238] pc : [<00000000>]    lr : [<bf2281f0>]    psr: 60000013
  [ 1461.949238] sp : dee0fe50  ip : dee0fe10  fp : dee0fe6c
  [ 1461.960761] r10: 00000000  r9 : 00000000  r8 : 00000000
  [ 1461.966006] r7 : dcabc7c0  r6 : df4164ec  r5 : 00000002  r4 : dcabc040
  [ 1461.972558] r3 : 00000000  r2 : 0000001a  r1 : 00000000  r0 : df4164ec
  [ 1461.979112] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
  [ 1461.986275] Control: 10c5387d  Table: 1e33c04a  DAC: 00000051
  [ 1461.992043] Process ash (pid: 759, stack limit = 0xdee0e210)
  [ 1461.997724] Stack: (0xdee0fe50 to 0xdee10000)
  [ 1462.002097] fe40:                                     bf228164 00000002 dee0ff80 dcabc7c0
  [ 1462.010309] fe60: dee0fe84 dee0fe70 c023f758 bf228170 c023f738 00000002 dee0fe9c dee0fe88
  [ 1462.018520] fe80: c0169310 c023f744 df4a1000 00000002 dee0fedc dee0fea0 c0168ab8 c01692d4
  [ 1462.026731] fea0: 00000000 00000000 df747c10 df4a100c d4aca1c9 df727a80 c01689c0 dee0ff80
  [ 1462.034943] fec0: 00000002 c000fc24 dee0e000 00000000 dee0ff4c dee0fee0 c0100c78 c01689cc
  [ 1462.043153] fee0: 00000000 dee0fee8 dee0ff14 dee0fef8 dee0ff14 dee0ff00 c0060668 c04640a0
  [ 1462.051365] ff00: dee0ff50 df621350 dee0ff4c dee0ff18 c00298f8 c0060630 fffffff6 dee0ff68
  [ 1462.059576] ff20: c00ff23c 00000007 00000002 df727a80 b6f092d0 dee0ff80 c000fc24 dee0e000
  [ 1462.067786] ff40: dee0ff7c dee0ff50 c0101ae4 c0100c50 00000003 00000007 df727a80 df727a80
  [ 1462.075997] ff60: b6f092d0 00000002 c000fc24 dee0e000 dee0ffa4 dee0ff80 c01028dc c0101a44
  [ 1462.084208] ff80: 00000000 00000000 00000000 00000000 ffffffff 00000004 00000000 dee0ffa8
  [ 1462.092419] ffa0: c000fa60 c010289c 00000000 00000000 00000001 b6f092d0 00000002 00000000
  [ 1462.100630] ffc0: 00000000 00000000 ffffffff 00000004 b6f092d0 00000020 00059ec0 00059ea0
  [ 1462.108841] ffe0: beb744f8 beb744e4 b6ee1904 b6ee0dc8 60000010 00000001 00000000 00000000
  [ 1462.117049] Backtrace:
  [ 1462.119521] [<bf228164>] (usbport_trig_port_store [ledtrig_usbport]) from [<c023f758>] (dev_attr_store+0x20/0x2c)
  [ 1462.129826]  r7:dcabc7c0 r6:dee0ff80 r5:00000002 r4:bf228164
  [ 1462.135511] [<c023f738>] (dev_attr_store) from [<c0169310>] (sysfs_kf_write+0x48/0x4c)
  [ 1462.143459]  r5:00000002 r4:c023f738
  [ 1462.147049] [<c01692c8>] (sysfs_kf_write) from [<c0168ab8>] (kernfs_fop_write+0xf8/0x1f8)
  [ 1462.155258]  r5:00000002 r4:df4a1000
  [ 1462.158850] [<c01689c0>] (kernfs_fop_write) from [<c0100c78>] (__vfs_write+0x34/0x120)
  [ 1462.166800]  r10:00000000 r9:dee0e000 r8:c000fc24 r7:00000002 r6:dee0ff80 r5:c01689c0
  [ 1462.174660]  r4:df727a80
  [ 1462.177204] [<c0100c44>] (__vfs_write) from [<c0101ae4>] (vfs_write+0xac/0x170)
  [ 1462.184543]  r9:dee0e000 r8:c000fc24 r7:dee0ff80 r6:b6f092d0 r5:df727a80 r4:00000002
  [ 1462.192319] [<c0101a38>] (vfs_write) from [<c01028dc>] (SyS_write+0x4c/0xa8)
  [ 1462.199396]  r9:dee0e000 r8:c000fc24 r7:00000002 r6:b6f092d0 r5:df727a80 r4:df727a80
  [ 1462.207174] [<c0102890>] (SyS_write) from [<c000fa60>] (ret_fast_syscall+0x0/0x3c)
  [ 1462.214774]  r7:00000004 r6:ffffffff r5:00000000 r4:00000000
  [ 1462.220456] Code: bad PC value
  [ 1462.223560] ---[ end trace 676638a3a12c7a56 ]---
  [ 1462.228197] Kernel panic - not syncing: Fatal exception
  [ 1462.233445] CPU1: stopping
  [ 1462.236165] CPU: 1 PID: 0 Comm: swapper/1 Tainted: G      D    O    4.9.0-rc6 #2
  [ 1462.243590] Hardware name: Marvell Armada 380/385 (Device Tree)
  [ 1462.249531] Backtrace:
  [ 1462.252001] [<c00138a8>] (dump_backtrace) from [<c0013b7c>] (show_stack+0x18/0x1c)
  [ 1462.259601]  r7:df47ff48 r6:60000193 r5:c07dea44 r4:00000000
  [ 1462.265285] [<c0013b64>] (show_stack) from [<c01b4fb8>] (dump_stack+0x94/0xa8)
  [ 1462.272538] [<c01b4f24>] (dump_stack) from [<c0016bdc>] (handle_IPI+0x178/0x198)
  [ 1462.279963]  r7:df47ff48 r6:00000000 r5:00000001 r4:c07f9230
  [ 1462.285645] [<c0016a64>] (handle_IPI) from [<c00094e4>] (gic_handle_irq+0x90/0x94)
  [ 1462.293245]  r7:df47ff48 r6:e080210c r5:c07cfbb8 r4:c07ded00
  [ 1462.298927] [<c0009454>] (gic_handle_irq) from [<c00146cc>] (__irq_svc+0x6c/0x90)
  [ 1462.306439] Exception stack(0xdf47ff48 to 0xdf47ff90)
  [ 1462.311510] ff40:                   00000001 00000000 00000000 c0020580 df47e000 c07cf02c
  [ 1462.319721] ff60: c07cf07c 00000002 00000000 00000000 c07ca378 df47ffa4 df47ffa8 df47ff98
  [ 1462.327932] ff80: c00105ac c00105b0 60000013 ffffffff
  [ 1462.333004]  r9:df47e000 r8:00000000 r7:df47ff7c r6:ffffffff r5:60000013 r4:c00105b0
  [ 1462.340781] [<c0010570>] (arch_cpu_idle) from [<c0463f4c>] (default_idle_call+0x28/0x34)
  [ 1462.348908] [<c0463f24>] (default_idle_call) from [<c0061494>] (cpu_startup_entry+0x118/0x1f0)
  [ 1462.357557] [<c006137c>] (cpu_startup_entry) from [<c0016808>] (secondary_start_kernel+0x150/0x15c)
  [ 1462.366638]  r7:c07f9240
  [ 1462.369181] [<c00166b8>] (secondary_start_kernel) from [<0000962c>] (0x962c)
  [ 1462.376256]  r5:00000051 r4:1f46406a
  [ 1462.379845] Rebooting in 3 seconds..


Would you happen to have an idea what is going wrong here?

Thanks
Ralph