Currently i am working on a A1H RSK based board using linux 4.9. Board is connected to the GSM UC20 module using USB method for communicating. The GSM module provide 5 ttyUSB ports (ttyUSB0, ttyUSB1, ttyUSB2, ttyUSB3, ttyUSB4 ). and ttyUSB2 is used for acessing AT commands and ttyUSB3 is for ppp connectivity. But getting kernel crash while turning off the GSM. What will be the reason for this, is it related to kernel problem?
Logs are attached in below.
option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
option 1-1:1.0: device disconnected
option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
option 1-1:1.1: device disconnected
Unable to handle kernel paging request at virtual address 5d35d856
pgd = c0004000
[5d35d856] *pgd=00000000
Internal error: Oops: 5 [#1] THUMB2
Modules linked in: ryb_phase_detector(O) led(O) lcd(O) keypad(O) gsm_uc20(O)
CPU: 0 PID: 5254 Comm: kworker/0:2 Tainted: G O 4.9.76-g727d873-dirty #56
Hardware name: Generic R7S72100 (Flattened Device Tree)
Workqueue: usb_hub_wq hub_event
task: c6a52bc0 task.stack: c78be000
PC is at pipe_setting+0x154/0x294
LR is at arm_heavy_mb+0xb/0x20
pc : [<bf9f5a50>] lr : [<bf80a647>] psr: 000e00b3
sp : c78bfd18 ip : 00000000 fp : ffffffed
r10: 00000000 r9 : c88ff000 r8 : c6a96b40
r7 : 00000000 r6 : c7ada580 r5 : 0000000b r4 : c797e930
r3 : 5d65cc4c r2 : 00000003 r1 : 0000000b r0 : 5d35d82a
Flags: nzcv IRQs off FIQs on Mode SVC_32 ISA Thumb Segment none
Control: 58c53c7d Table: 0eba4059 DAC: 00000051
Process kworker/0:2 (pid: 5254, stack limit = 0xc78be208)
Stack: (0xc78bfd18 to 0xc78c0000)
fd00: 00000000 c797e930
fd20: c6a96b40 0000000e c797e9a0 c7ada580 c6a96b48 bf9f60a3 c6a96b48 c797e930
fd40: c6a96b40 0000000e c797e9a0 ffffff94 c6a96b48 00000000 ffffffed bf9f62b7
fd60: c7aebf80 c797e930 c6aa3680 00000000 c7aebf80 200e0093 ffffff94 bf9f69cb
fd80: ffffff94 c7aebf80 ffffff94 c7aebf80 c7bb4138 c7aebf94 c7bb4150 c797e800
fda0: c798c4b0 bf9e3153 c7bb4138 c7a5fc00 c7a5fc00 00000000 00000038 bf9e4971
fdc0: c7bb4138 00000002 c6aa2688 bf9e49b7 c6929a20 c7a5fc70 c7a5fc00 c797e800
fde0: c6929a00 bf9e5f53 c6929a20 00000004 00000002 c6929a20 c798c4b0 c0033de0
fe00: c797e800 c6929a00 c7a37800 ffffffed c7a37a00 bf98b4df c6929a44 c6929a54
fe20: c6929a20 bf98b53f c6929a44 c6929a20 c7b85c2c bf98ac97 c6929a20 00000000
fe40: c7a5fc70 bf989603 c7bb4138 bf9e860b c6929a00 bf9e46dd 00000007 c7a5fc00
fe60: 00000000 00000002 c797e800 bf9e4a85 00000000 c7a5fc00 00000000 00000000
fe80: c7a5fc70 c7a5fca4 c7a37800 bf9df9d3 c7a37afc 00000001 00000402 c797fc00
fea0: c7a37800 00000001 ffffffed bf9e0951 ffffffff 00000000 00000001 c797fc00
fec0: c797e800 00000001 c7a37a7d 00000000 c7a37c20 c7a37c00 c797fca4 c7a37974
fee0: c7a37974 c7a37808 00000000 c7b88140 00010402 c79e9700 c696de00 c7a72700
ff00: c7a37afc c001f204 00000000 c7ee8300 00000000 c7a72718 00000008 bf81b511
ff20: c7a72700 c7a37afc c7a72700 c001f204 c001f204 c78be000 c001f218 c0022e00
ff40: c7a72718 bf81bc27 00000000 c6aa2100 00000000 c7a72700 bf81ba6d 00000000
ff60: 00000000 00000000 00000000 bf81e627 c6a52d68 00000000 00000000 c7a72700
ff80: 00000000 c78bff84 c78bff84 00000000 c78bff90 c78bff90 ffffffff c6aa2100
ffa0: bf81e5a7 00000000 00000000 bf805101 00000000 00000000 00000000 00000000
ffc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
ffe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000
[<bf9f5a50>] (pipe_setting) from [<bf9f60a3>] (start_transfer+0x513/0x65c)
[<bf9f60a3>] (start_transfer) from [<bf9f62b7>] (finish_request+0xcb/0xda)
[<bf9f62b7>] (finish_request) from [<bf9f69cb>] (r8a66597_urb_dequeue+0x4b/0x56)
[<bf9f69cb>] (r8a66597_urb_dequeue) from [<bf9e3153>] (usb_hcd_flush_endpoint+0x45/0x76)
[<bf9e3153>] (usb_hcd_flush_endpoint) from [<bf9e4971>] (usb_disable_endpoint+0x41/0x5a)
[<bf9e4971>] (usb_disable_endpoint) from [<bf9e49b7>] (usb_disable_interface+0x2d/0x2e)
[<bf9e49b7>] (usb_disable_interface) from [<bf9e5f53>] (usb_unbind_interface+0x4b/0x158)
[<bf9e5f53>] (usb_unbind_interface) from [<bf98b4df>] (__device_release_driver+0x49/0x94)
[<bf98b4df>] (__device_release_driver) from [<bf98b53f>] (device_release_driver+0x15/0x1e)
[<bf98b53f>] (device_release_driver) from [<bf98ac97>] (bus_remove_device+0x73/0x90)
[<bf98ac97>] (bus_remove_device) from [<bf989603>] (device_del+0xbd/0x132)
[<bf989603>] (device_del) from [<bf9e4a85>] (usb_disable_device+0xcd/0x11e)
[<bf9e4a85>] (usb_disable_device) from [<bf9df9d3>] (usb_disconnect+0x49/0x10e)
[<bf9df9d3>] (usb_disconnect) from [<bf9e0951>] (hub_event+0x421/0xa50)
[<bf9e0951>] (hub_event) from [<bf81b511>] (process_one_work+0x103/0x1e2)
[<bf81b511>] (process_one_work) from [<bf81bc27>] (worker_thread+0x1bb/0x288)
[<bf81bc27>] (worker_thread) from [<bf81e627>] (kthread+0x81/0x92)
[<bf81e627>] (kthread) from [<bf805101>] (ret_from_fork+0x11/0x30)
Code: 35c3 f3c1 11c0 310a (f850) 2021
---[ end trace 523e122004ea6f90 ]---