linux/drivers/tty
Liwei Song a9b01b5823 serial: 8250_mid fix calltrace when hotplug 8250 serial controller
Fix the following Calltrace:
[   77.768221] WARNING: CPU: 5 PID: 645 at drivers/dma/dmaengine.c:1069 dma_async_device_unregister+0xe2/0xf0
[   77.775058] dma_async_device_unregister called while 1 clients hold a reference
[   77.825048] CPU: 5 PID: 645 Comm: sh Not tainted 4.8.8-WR9.0.0.0_standard+ #3
[   77.832550] Hardware name: Intel Corp. Aspen Cove/Server, BIOS HAVLCRB1.X64.0012.D58.1604140405 04/14/2016
[   77.840396]  0000000000000000 ffffc90008adbc80 ffffffff81403456 ffffc90008adbcd0
[   77.848245]  0000000000000000 ffffc90008adbcc0 ffffffff8105e2e1 0000042d08adbf20
[   77.855934]  ffff88046a861c18 ffff88046a85c420 ffffffff820d4200 ffff88046ae92318
[   77.863601] Call Trace:
[   77.871113]  [<ffffffff81403456>] dump_stack+0x4f/0x69
[   77.878655]  [<ffffffff8105e2e1>] __warn+0xd1/0xf0
[   77.886102]  [<ffffffff8105e34f>] warn_slowpath_fmt+0x4f/0x60
[   77.893508]  [<ffffffff814187a9>] ? find_next_bit+0x19/0x20
[   77.900730]  [<ffffffff814bf83e>] ? dma_channel_rebalance+0x23e/0x270
[   77.907814]  [<ffffffff814bfee2>] dma_async_device_unregister+0xe2/0xf0
[   77.914992]  [<ffffffff814c53aa>] hsu_dma_remove+0x1a/0x60
[   77.921977]  [<ffffffff814ee14c>] dnv_exit+0x1c/0x20
[   77.928752]  [<ffffffff814edff6>] mid8250_remove+0x26/0x40
[   77.935607]  [<ffffffff8144f1b9>] pci_device_remove+0x39/0xc0
[   77.942292]  [<ffffffff8160cfea>] __device_release_driver+0x9a/0x140
[   77.948836]  [<ffffffff8160d0b3>] device_release_driver+0x23/0x30
[   77.955364]  [<ffffffff81447dcc>] pci_stop_bus_device+0x8c/0xa0
[   77.961769]  [<ffffffff81447f0a>] pci_stop_and_remove_bus_device_locked+0x1a/0x30
[   77.968113]  [<ffffffff81450d4e>] remove_store+0x5e/0x70
[   77.974267]  [<ffffffff81607ed8>] dev_attr_store+0x18/0x30
[   77.980243]  [<ffffffff8123006a>] sysfs_kf_write+0x3a/0x50
[   77.986180]  [<ffffffff8122f5ab>] kernfs_fop_write+0x10b/0x190
[   77.992118]  [<ffffffff811bf1c8>] __vfs_write+0x18/0x40
[   77.998032]  [<ffffffff811bfdee>] vfs_write+0xae/0x190
[   78.003747]  [<ffffffff811c1016>] SyS_write+0x46/0xb0
[   78.009234]  [<ffffffff81a4c31b>] entry_SYSCALL_64_fastpath+0x13/0x8f
[   78.014809] ---[ end trace 0c36dd73b7408eb2 ]---

This happens when the 8250 serial controller is hotplugged as follows:
echo 1 > /sys/bus/pci/devices/0000:00:1a.0/remove

This trace happens due to the serial port still holding a reference when
the dma device is unregistered.
The dma unregister routine will check if there is still a reference exist,
if so it will give the WARNING(here serial port still was not unregister).

To fix this, We need to unregister the serial port first, then do DMA
device unregister to make sure there is no reference when to DMA routine.

Signed-off-by: Liwei Song <liwei.song@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-11-30 13:06:08 +01:00
..
hvc tty/hvc: Use opal irqchip interface if available 2016-07-27 12:38:20 +10:00
ipwireless tty: ipwireless, cleanup TIOCGSERIAL 2016-06-25 08:56:30 -07:00
serial serial: 8250_mid fix calltrace when hotplug 8250 serial controller 2016-11-30 13:06:08 +01:00
vt console: Move userspace I/O out of console_lock to fix lockdep warning 2016-11-29 21:42:40 +01:00
amiserial.c tty: amiserial: fix invalid user-pointer check 2016-11-10 14:41:25 +01:00
bfin_jtag_comm.c
cyclades.c tty: stop defining STD_COM_FLAGS in drivers 2016-06-25 08:56:30 -07:00
ehv_bytechan.c drivers/tty: make ehv_bytechan.c explicitly non-modular 2016-02-06 23:26:43 -08:00
goldfish.c tty: goldfish: support platform_device with id -1 2016-03-07 16:11:14 -08:00
isicom.c tty: Replace ASYNC_INITIALIZED bit and update atomically 2016-04-30 09:26:55 -07:00
Kconfig devpts: Make each mount of devpts an independent filesystem. 2016-06-05 10:36:01 -07:00
Makefile
metag_da.c timers, drivers/tty/metag_da: Initialize the poll timer as pinned 2016-07-07 10:25:14 +02:00
mips_ejtag_fdc.c timers, drivers/tty/mips_ejtag: Initialize the poll timer as pinned 2016-07-07 10:34:59 +02:00
moxa.c tty: Replace ASYNC_INITIALIZED bit and update atomically 2016-04-30 09:26:55 -07:00
moxa.h
mxser.c tty: cyclades+mxser, do not initialize to zero 2016-06-25 08:56:30 -07:00
mxser.h
n_gsm.c TTY and Serial driver update for 4.7-rc1 2016-05-20 20:57:27 -07:00
n_hdlc.c Fix OpenSSH pty regression on close 2016-05-01 13:22:54 -07:00
n_r3964.c
n_tracerouter.c
n_tracesink.c
n_tracesink.h
n_tty.c Fix OpenSSH pty regression on close 2016-05-01 13:22:54 -07:00
nozomi.c tty: nozomi: avoid sprintf buffer overflow 2016-11-29 20:20:07 +01:00
pty.c pty: make ptmx file ops read-only after init 2016-09-15 12:47:03 +02:00
rocket_int.h tty: rocket: Remove private close_wait 2016-01-28 14:13:44 -08:00
rocket.c tty: rocket: fix invalid user-pointer checks 2016-11-10 14:41:25 +01:00
rocket.h
synclink_gt.c TTY and Serial driver update for 4.7-rc1 2016-05-20 20:57:27 -07:00
synclink.c TTY and Serial driver update for 4.7-rc1 2016-05-20 20:57:27 -07:00
synclinkmp.c TTY and Serial driver update for 4.7-rc1 2016-05-20 20:57:27 -07:00
sysrq.c Revert "drivers/tty: Explicitly pass current to show_stack" 2016-09-28 08:12:27 +02:00
tty_audit.c tty: audit: remove unused variable 2016-03-07 16:11:14 -08:00
tty_buffer.c Fix OpenSSH pty regression on close 2016-05-01 13:22:54 -07:00
tty_io.c Merge 4.6-rc7 into tty-next 2016-05-09 09:39:13 +02:00
tty_ioctl.c tty: Replace TTY_THROTTLED bit tests with tty_throttled() 2016-04-30 09:26:55 -07:00
tty_ldisc.c tty: Eliminate global symbol tty_ldisc_N_TTY 2016-01-27 15:13:28 -08:00
tty_ldsem.c tty: Deinline __ldsem_down_write_nested, save 128 bytes 2015-12-13 19:59:48 -08:00
tty_mutex.c Merge 4.5-rc4 into tty-next 2016-02-14 14:36:04 -08:00
tty_port.c tty: Replace ASYNC_INITIALIZED bit and update atomically 2016-04-30 09:26:55 -07:00