linux-toradex.git/drivers/tty, branch v4.9.73

tty: fix data race in tty_ldisc_ref_wait()

2017-12-20T09:07:26+00:00

[ Upstream commit a4a3e061149f09c075f108b6f1cf04d9739a6bc2 ]

tty_ldisc_ref_wait() checks tty->ldisc under tty->ldisc_sem.
But if ldisc==NULL it releases them sem and reloads
tty->ldisc without holding the sem. This is wrong and
can lead to returning non-NULL ldisc without protection.

Don't reload tty->ldisc second time.

Signed-off-by: Dmitry Vyukov 
Cc: syzkaller@googlegroups.com
Cc: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Cc: Peter Hurley 
Cc: One Thousand Gnomes 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

tty: don't panic on OOM in tty_set_ldisc()

2017-12-20T09:07:25+00:00

[ Upstream commit 5362544bebe85071188dd9e479b5a5040841c895 ]

If tty_ldisc_open() fails in tty_set_ldisc(), it tries to go back
to the old discipline or N_TTY. But that can fail as well, in such
case it panics. This is not a graceful way to handle OOM.

Leave ldisc==NULL if all attempts fail instead.
Also use existing tty_ldisc_reinit() helper function instead of
tty_ldisc_restore(). Also don't WARN/BUG in tty_ldisc_reinit()
if N_TTY fails, which would have the same net effect of bringing
kernel down on OOM. Instead print a single line message about
what has happened.

Signed-off-by: Dmitry Vyukov 
Cc: syzkaller@googlegroups.com
Cc: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Cc: Peter Hurley 
Cc: One Thousand Gnomes 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

sysrq : fix Show Regs call trace on ARM

2017-12-09T21:01:49+00:00

[ Upstream commit b00bebbc301c8e1f74f230dc82282e56b7e7a6db ]

When kernel configuration SMP,PREEMPT and DEBUG_PREEMPT are enabled,
echo 1 >/proc/sys/kernel/sysrq
echo p >/proc/sysrq-trigger
kernel will print call trace as below:

sysrq: SysRq : Show Regs
BUG: using __this_cpu_read() in preemptible [00000000] code: sh/435
caller is __this_cpu_preempt_check+0x18/0x20
Call trace:
[] dump_backtrace+0x0/0x1d0
[] show_stack+0x24/0x30
[] dump_stack+0x90/0xb0
[] check_preemption_disabled+0x100/0x108
[] __this_cpu_preempt_check+0x18/0x20
[] sysrq_handle_showregs+0x1c/0x40
[] __handle_sysrq+0x12c/0x1a0
[] write_sysrq_trigger+0x60/0x70
[] proc_reg_write+0x90/0xd0
[] __vfs_write+0x48/0x90
[] vfs_write+0xa4/0x190
[] SyS_write+0x54/0xb0
[] el0_svc_naked+0x24/0x28

This can be seen on a common board like an r-pi3.
This happens because when echo p >/proc/sysrq-trigger,
get_irq_regs() is called outside of IRQ context,
if preemption is enabled in this situation,kernel will
print the call trace. Since many prior discussions on
the mailing lists have made it clear that get_irq_regs
either just returns NULL or stale data when used outside
of IRQ context,we simply avoid calling it outside of
IRQ context.

Signed-off-by: Jibin Xu 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

serial: 8250: Preserve DLD[7:4] for PORT_XR17V35X

2017-12-09T21:01:48+00:00

[ Upstream commit 0ab84da2e076948c49d36197ee7d254125c53eab ]

The upper four bits of the XR17V35x fractional divisor register (DLD)
control general chip function (RS-485 direction pin polarity, multidrop
mode, XON/XOFF parity check, and fast IR mode). Don't allow these bits
to be clobbered when setting the baudrate.

Signed-off-by: Aaron Sierra 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

serial: 8250_fintek: Fix rs485 disablement on invalid ioctl()

2017-12-09T21:01:48+00:00

[ Upstream commit 3236a965486ba0c6043cf2c7b51943d8b382ae29 ]

This driver's ->rs485_config callback checks if SER_RS485_RTS_ON_SEND
and SER_RS485_RTS_AFTER_SEND have the same value.  If they do, it means
the user has passed in invalid data with the TIOCSRS485 ioctl()
since RTS must have a different polarity when sending and when not
sending.  In this case, rs485 mode is not enabled (the RS485_URA bit
is not set in the RS485 Enable Register) and this is supposed to be
signaled back to the user by clearing the SER_RS485_ENABLED bit in
struct serial_rs485 ... except a missing tilde character is preventing
that from happening.

Fixes: 28e3fb6c4dce ("serial: Add support for Fintek F81216A LPC to 4 UART")
Cc: Ricardo Ribalda Delgado 
Cc: "Ji-Ze Hong (Peter Hong)" 
Signed-off-by: Lukas Wunner 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

serial: 8250_pci: Add Amazon PCI serial device ID

2017-12-09T21:01:47+00:00

commit 3bfd1300abfe3adb18e84a89d97a0e82a22124bb upstream.

This device will be used in future Amazon EC2 instances as the primary
serial port (i.e., data sent to this port will be available via the
GetConsoleOuput [1] EC2 API).

[1] http://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_GetConsoleOutput.html

Signed-off-by: Matt Wilson 
Signed-off-by: Greg Kroah-Hartman

serial: 8250_fintek: Fix finding base_port with activated SuperIO

2017-11-24T07:33:42+00:00

commit fd97e66c5529046e989a0879c3bb58fddb592c71 upstream.

The SuperIO will be configured at boot time by BIOS, but some BIOS
will not deactivate the SuperIO when the end of configuration. It'll
lead to mismatch for pdata->base_port in probe_setup_port(). So we'll
deactivate all SuperIO before activate special base_port in
fintek_8250_enter_key().

Tested on iBASE MI802.

Tested-by: Ji-Ze Hong (Peter Hong) 
Signed-off-by: Ji-Ze Hong (Peter Hong) 
Reviewd-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

serial: omap: Fix EFR write on RTS deassertion

2017-11-24T07:33:42+00:00

commit 2a71de2f7366fb1aec632116d0549ec56d6a3940 upstream.

Commit 348f9bb31c56 ("serial: omap: Fix RTS handling") sought to enable
auto RTS upon manual RTS assertion and disable it on deassertion.
However it seems the latter was done incorrectly, it clears all bits in
the Extended Features Register *except* auto RTS.

Fixes: 348f9bb31c56 ("serial: omap: Fix RTS handling")
Cc: Peter Hurley 
Signed-off-by: Lukas Wunner 
Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: Fix register offsets for the IRDA serial port

2017-11-15T14:53:14+00:00

[ Upstream commit a752ba18af8285e3eeda572f40dddaebff0c3621 ]

Even though most of its registers are 8-bit wide, the IRDA has two
16-bit registers that make it a 16-bit peripheral and not a 8-bit
peripheral with addresses shifted by one. Fix the registers offset in
the driver and the platform data regshift value.

Signed-off-by: Laurent Pinchart 
Reviewed-by: Geert Uytterhoeven 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

sparc64: Migrate hvcons irq to panicked cpu

2017-10-21T15:21:35+00:00

[ Upstream commit 7dd4fcf5b70694dc961eb6b954673e4fc9730dbd ]

On panic, all other CPUs are stopped except the one which had
hit panic. To keep console alive, we need to migrate hvcons irq
to panicked CPU.

Signed-off-by: Vijay Kumar 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman