linux-stable.git/drivers/tty, branch v4.4.181

tty: max310x: Fix external crystal register setup

2019-06-11T10:24:10+00:00

commit 5d24f455c182d5116dd5db8e1dc501115ecc9c2c upstream.

The datasheet states:

  Bit 4: ClockEnSet the ClockEn bit high to enable an external clocking
(crystal or clock generator at XIN). Set the ClockEn bit to 0 to disable
clocking
  Bit 1: CrystalEnSet the CrystalEn bit high to enable the crystal
oscillator. When using an external clock source at XIN, CrystalEn must
be set low.

The bit 4, MAX310X_CLKSRC_EXTCLK_BIT, should be set and was not.

This was required to make the MAX3107 with an external crystal on our
board able to send or receive data.

Signed-off-by: Joe Burmeister 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

tty: serial: msm_serial: Fix XON/XOFF

2019-06-11T10:24:10+00:00

commit 61c0e37950b88bad590056286c1d766b1f167f4e upstream.

When the tty layer requests the uart to throttle, the current code
executing in msm_serial will trigger "Bad mode in Error Handler" and
generate an invalid stack frame in pstore before rebooting (that is if
pstore is indeed configured: otherwise the user shall just notice a
reboot with no further information dumped to the console).

This patch replaces the PIO byte accessor with the word accessor
already used in PIO mode.

Fixes: 68252424a7c7 ("tty: serial: msm: Support big-endian CPUs")
Cc: stable@vger.kernel.org
Signed-off-by: Jorge Ramirez-Ortiz 
Reviewed-by: Bjorn Andersson 
Reviewed-by: Stephen Boyd 
Signed-off-by: Greg Kroah-Hartman

tty: ipwireless: fix missing checks for ioremap

2019-06-11T10:24:04+00:00

[ Upstream commit 1bbb1c318cd8a3a39e8c3e2e83d5e90542d6c3e3 ]

ipw->attr_memory and ipw->common_memory are assigned with the
return value of ioremap. ioremap may fail, but no checks
are enforced. The fix inserts the checks to avoid potential
NULL pointer dereferences.

Signed-off-by: Kangjie Lu 
Reviewed-by: David Sterba 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty/vt: fix write/write race in ioctl(KDSKBSENT) handler

2019-06-11T10:23:37+00:00

commit 46ca3f735f345c9d87383dd3a09fa5d43870770e upstream.

The bug manifests as an attempt to access deallocated memory:

    BUG: unable to handle kernel paging request at ffff9c8735448000
    #PF error: [PROT] [WRITE]
    PGD 288a05067 P4D 288a05067 PUD 288a07067 PMD 7f60c2063 PTE 80000007f5448161
    Oops: 0003 [#1] PREEMPT SMP
    CPU: 6 PID: 388 Comm: loadkeys Tainted: G         C        5.0.0-rc6-00153-g5ded5871030e #91
    Hardware name: Gigabyte Technology Co., Ltd. To be filled by O.E.M./H77M-D3H, BIOS F12 11/14/2013
    RIP: 0010:__memmove+0x81/0x1a0
    Code: 4c 89 4f 10 4c 89 47 18 48 8d 7f 20 73 d4 48 83 c2 20 e9 a2 00 00 00 66 90 48 89 d1 4c 8b 5c 16 f8 4c 8d 54 17 f8 48 c1 e9 03  48 a5 4d 89 1a e9 0c 01 00 00 0f 1f 40 00 48 89 d1 4c 8b 1e 49
    RSP: 0018:ffffa1b9002d7d08 EFLAGS: 00010203
    RAX: ffff9c873541af43 RBX: ffff9c873541af43 RCX: 00000c6f105cd6bf
    RDX: 0000637882e986b6 RSI: ffff9c8735447ffb RDI: ffff9c8735447ffb
    RBP: ffff9c8739cd3800 R08: ffff9c873b802f00 R09: 00000000fffff73b
    R10: ffffffffb82b35f1 R11: 00505b1b004d5b1b R12: 0000000000000000
    R13: ffff9c873541af3d R14: 000000000000000b R15: 000000000000000c
    FS:  00007f450c390580(0000) GS:ffff9c873f180000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: ffff9c8735448000 CR3: 00000007e213c002 CR4: 00000000000606e0
    Call Trace:
     vt_do_kdgkb_ioctl+0x34d/0x440
     vt_ioctl+0xba3/0x1190
     ? __bpf_prog_run32+0x39/0x60
     ? mem_cgroup_commit_charge+0x7b/0x4e0
     tty_ioctl+0x23f/0x920
     ? preempt_count_sub+0x98/0xe0
     ? __seccomp_filter+0x67/0x600
     do_vfs_ioctl+0xa2/0x6a0
     ? syscall_trace_enter+0x192/0x2d0
     ksys_ioctl+0x3a/0x70
     __x64_sys_ioctl+0x16/0x20
     do_syscall_64+0x54/0xe0
     entry_SYSCALL_64_after_hwframe+0x49/0xbe

The bug manifests on systemd systems with multiple vtcon devices:
  # cat /sys/devices/virtual/vtconsole/vtcon0/name
  (S) dummy device
  # cat /sys/devices/virtual/vtconsole/vtcon1/name
  (M) frame buffer device

There systemd runs 'loadkeys' tool in tapallel for each vtcon
instance. This causes two parallel ioctl(KDSKBSENT) calls to
race into adding the same entry into 'func_table' array at:

    drivers/tty/vt/keyboard.c:vt_do_kdgkb_ioctl()

The function has no locking around writes to 'func_table'.

The simplest reproducer is to have initrams with the following
init on a 8-CPU machine x86_64:

    #!/bin/sh

    loadkeys -q windowkeys ru4 &
    loadkeys -q windowkeys ru4 &
    loadkeys -q windowkeys ru4 &
    loadkeys -q windowkeys ru4 &

    loadkeys -q windowkeys ru4 &
    loadkeys -q windowkeys ru4 &
    loadkeys -q windowkeys ru4 &
    loadkeys -q windowkeys ru4 &
    wait

The change adds lock on write path only. Reads are still racy.

CC: Greg Kroah-Hartman 
CC: Jiri Slaby 
Link: https://lkml.org/lkml/2019/2/17/256
Signed-off-by: Sergei Trofimovich 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

sc16is7xx: missing unregister/delete driver on error in sc16is7xx_init()

2019-05-16T17:44:57+00:00

[ Upstream commit ac0cdb3d990108df795b676cd0d0e65ac34b2273 ]

Add the missing uart_unregister_driver() and i2c_del_driver() before return
from sc16is7xx_init() in the error handling case.

Signed-off-by: Mao Wenan 
Reviewed-by: Vladimir Zapolskiy 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin (Microsoft)

serial: uartps: console_setup() can't be placed to init section

2019-04-27T07:33:58+00:00

[ Upstream commit 4bb1ce2350a598502b23088b169e16b43d4bc639 ]

When console device is rebinded, console_setup() is called again.
But marking it as __init means that function will be clear after boot is
complete. If console device is binded again console_setup() is not found
and error "Unable to handle kernel paging request at virtual address"
is reported.

Signed-off-by: Michal Simek 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: ldisc: add sysctl to prevent autoloading of ldiscs

2019-04-27T07:33:54+00:00

commit 7c0cca7c847e6e019d67b7d793efbbe3b947d004 upstream.

By default, the kernel will automatically load the module of any line
dicipline that is asked for.  As this sometimes isn't the safest thing
to do, provide a sysctl to disable this feature.

By default, we set this to 'y' as that is the historical way that Linux
has worked, and we do not want to break working systems.  But in the
future, perhaps this can default to 'n' to prevent this functionality.

Signed-off-by: Greg Kroah-Hartman 
Reviewed-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

tty: increase the default flip buffer limit to 2*640K

2019-04-27T07:33:52+00:00

[ Upstream commit 7ab57b76ebf632bf2231ccabe26bea33868118c6 ]

We increase the default limit for buffer memory allocation by a factor of
10 to 640K to prevent data loss when using fast serial interfaces.

For example when using RS485 without flow-control at speeds of 1Mbit/s
an upwards we've run into problems such as applications being too slow
to read out this buffer (on embedded devices based on imx53 or imx6).

If you want to write transmitted data to a slow SD card and thus have
realtime requirements, this limit can become a problem.

That shouldn't be the case and 640K buffers fix such problems for us.

This value is a maximum limit for allocation only. It has no effect
on systems that currently run fine. When transmission is slow enough
applications and hardware can keep up and increasing this limit
doesn't change anything.

It only _allows_ to allocate more than 2*64K in cases we currently fail to
allocate memory despite having some.

Signed-off-by: Manfred Schlaegl 
Signed-off-by: Martin Kepplinger 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty/serial: atmel: RS485 HD w/DMA: enable RX after TX is stopped

2019-04-27T07:33:47+00:00

commit 69646d7a3689fbe1a65ae90397d22ac3f1b8d40f upstream.

In half-duplex operation, RX should be started after TX completes.

If DMA is used, there is a case when the DMA transfer completes but the
TX FIFO is not emptied, so the RX cannot be restarted just yet.

Use a boolean variable to store this state and rearm TX interrupt mask
to be signaled again that the transfer finished. In interrupt transmit
handler this variable is used to start RX. A warning message is generated
if RX is activated before TX fifo is cleared.

Fixes: b389f173aaa1 ("tty/serial: atmel: RS485 half duplex w/DMA: enable
RX after TX is done")
Signed-off-by: Razvan Stefanescu 
Acked-by: Richard Genoud 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

tty/serial: atmel: Add is_half_duplex helper

2019-04-27T07:33:47+00:00

commit f3040983132bf3477acd45d2452a906e67c2fec9 upstream.

Use a helper function to check that a port needs to use half duplex
communication, replacing several occurrences of multi-line bit checking.

Fixes: b389f173aaa1 ("tty/serial: atmel: RS485 half duplex w/DMA: enable RX after TX is done")
Cc: stable 
Signed-off-by: Razvan Stefanescu 
Acked-by: Richard Genoud 
Signed-off-by: Greg Kroah-Hartman