linux-stable.git/drivers/tty, branch v4.4.293

tty: tty_buffer: Fix the softlockup issue in flush_to_ldisc

2021-11-26T10:58:42+00:00

[ Upstream commit 3968ddcf05fb4b9409cd1859feb06a5b0550a1c1 ]

When running ltp testcase(ltp/testcases/kernel/pty/pty04.c) with arm64, there is a soft lockup,
which look like this one:

  Workqueue: events_unbound flush_to_ldisc
  Call trace:
   dump_backtrace+0x0/0x1ec
   show_stack+0x24/0x30
   dump_stack+0xd0/0x128
   panic+0x15c/0x374
   watchdog_timer_fn+0x2b8/0x304
   __run_hrtimer+0x88/0x2c0
   __hrtimer_run_queues+0xa4/0x120
   hrtimer_interrupt+0xfc/0x270
   arch_timer_handler_phys+0x40/0x50
   handle_percpu_devid_irq+0x94/0x220
   __handle_domain_irq+0x88/0xf0
   gic_handle_irq+0x84/0xfc
   el1_irq+0xc8/0x180
   slip_unesc+0x80/0x214 [slip]
   tty_ldisc_receive_buf+0x64/0x80
   tty_port_default_receive_buf+0x50/0x90
   flush_to_ldisc+0xbc/0x110
   process_one_work+0x1d4/0x4b0
   worker_thread+0x180/0x430
   kthread+0x11c/0x120

In the testcase pty04, The first process call the write syscall to send
data to the pty master. At the same time, the workqueue will do the
flush_to_ldisc to pop data in a loop until there is no more data left.
When the sender and workqueue running in different core, the sender sends
data fastly in full time which will result in workqueue doing work in loop
for a long time and occuring softlockup in flush_to_ldisc with kernel
configured without preempt. So I add need_resched check and cond_resched
in the flush_to_ldisc loop to avoid it.

Signed-off-by: Guanghui Feng 
Link: https://lore.kernel.org/r/1633961304-24759-1-git-send-email-guanghuifeng@linux.alibaba.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250_dw: Drop wrong use of ACPI_PTR()

2021-11-26T10:58:40+00:00

[ Upstream commit ebabb77a2a115b6c5e68f7364b598310b5f61fb2 ]

ACPI_PTR() is more harmful than helpful. For example, in this case
if CONFIG_ACPI=n, the ID table left unused which is not what we want.

Instead of adding ifdeffery here and there, drop ACPI_PTR().

Fixes: 6a7320c4669f ("serial: 8250_dw: Add ACPI 5.0 support")
Reported-by: Daniel Palmer 
Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20211005134516.23218-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: Fix out-of-bound vmalloc access in imageblit

2021-10-06T08:22:24+00:00

[ Upstream commit 3b0c406124719b625b1aba431659f5cdc24a982c ]

This issue happens when a userspace program does an ioctl
FBIOPUT_VSCREENINFO passing the fb_var_screeninfo struct
containing only the fields xres, yres, and bits_per_pixel
with values.

If this struct is the same as the previous ioctl, the
vc_resize() detects it and doesn't call the resize_screen(),
leaving the fb_var_screeninfo incomplete. And this leads to
the updatescrollmode() calculates a wrong value to
fbcon_display->vrows, which makes the real_y() return a
wrong value of y, and that value, eventually, causes
the imageblit to access an out-of-bound address value.

To solve this issue I made the resize_screen() be called
even if the screen does not need any resizing, so it will
"fix and fill" the fb_var_screeninfo independently.

Cc: stable  # after 5.15-rc2 is out, give it time to bake
Reported-and-tested-by: syzbot+858dc7a2f7ef07c2c219@syzkaller.appspotmail.com
Signed-off-by: Igor Matheus Andrade Torrente 
Link: https://lore.kernel.org/r/20210628134509.15895-1-igormtorrente@gmail.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250_pci: make setup_port() parameters explicitly unsigned

2021-09-22T09:41:25+00:00

[ Upstream commit 3a96e97ab4e835078e6f27b7e1c0947814df3841 ]

The bar and offset parameters to setup_port() are used in pointer math,
and while it would be very difficult to get them to wrap as a negative
number, just be "safe" and make them unsigned so that static checkers do
not trip over them unintentionally.

Cc: Jiri Slaby 
Reported-by: Jordy Zomer 
Link: https://lore.kernel.org/r/20210726130717.2052096-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

hvsi: don't panic on tty_register_driver failure

2021-09-22T09:41:25+00:00

[ Upstream commit 7ccbdcc4d08a6d7041e4849219bbb12ffa45db4c ]

The alloc_tty_driver failure is handled gracefully in hvsi_init. But
tty_register_driver is not. panic is called if that one fails.

So handle the failure of tty_register_driver gracefully too. This will
keep at least the console functional as it was enabled earlier by
console_initcall in hvsi_console_init. Instead of shooting down the
whole system.

This means, we disable interrupts and restore hvsi_wait back to
poll_for_state().

Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20210723074317.32690-3-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250: Define RX trigger levels for OxSemi 950 devices

2021-09-22T09:41:25+00:00

[ Upstream commit d7aff291d069c4418285f3c8ee27b0ff67ce5998 ]

Oxford Semiconductor 950 serial port devices have a 128-byte FIFO and in
the enhanced (650) mode, which we select in `autoconfig_has_efr' with
the ECB bit set in the EFR register, they support the receive interrupt
trigger level selectable with FCR bits 7:6 from the set of 16, 32, 112,
120.  This applies to the original OX16C950 discrete UART[1] as well as
950 cores embedded into more complex devices.

For these devices we set the default to 112, which sets an excessively
high level of 112 or 7/8 of the FIFO capacity, unlike with other port
types where we choose at most 1/2 of their respective FIFO capacities.
Additionally we don't make the trigger level configurable.  Consequently
frequent input overruns happen with high bit rates where hardware flow
control cannot be used (e.g. terminal applications) even with otherwise
highly-performant systems.

Lower the default receive interrupt trigger level to 32 then, and make
it configurable.  Document the trigger levels along with other port
types, including the set of 16, 32, 64, 112 for the transmit interrupt
as well[2].

References:

[1] "OX16C950 rev B High Performance UART with 128 byte FIFOs", Oxford
    Semiconductor, Inc., DS-0031, Sep 05, Table 10: "Receiver Trigger
    Levels", p. 22

[2] same, Table 9: "Transmit Interrupt Trigger Levels", p. 22

Signed-off-by: Maciej W. Rozycki 
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2106260608480.37803@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: serial: jsm: hold port lock when reporting modem line changes

2021-09-22T09:41:24+00:00

[ Upstream commit 240e126c28df084222f0b661321e8e3ecb0d232e ]

uart_handle_dcd_change() requires a port lock to be held and will emit a
warning when lockdep is enabled.

Held corresponding lock to fix the following warnings.

[  132.528648] WARNING: CPU: 5 PID: 11600 at drivers/tty/serial/serial_core.c:3046 uart_handle_dcd_change+0xf4/0x120
[  132.530482] Modules linked in:
[  132.531050] CPU: 5 PID: 11600 Comm: jsm Not tainted 5.14.0-rc1-00003-g7fef2edf7cc7-dirty #31
[  132.535268] RIP: 0010:uart_handle_dcd_change+0xf4/0x120
[  132.557100] Call Trace:
[  132.557562]  ? __free_pages+0x83/0xb0
[  132.558213]  neo_parse_modem+0x156/0x220
[  132.558897]  neo_param+0x399/0x840
[  132.559495]  jsm_tty_open+0x12f/0x2d0
[  132.560131]  uart_startup.part.18+0x153/0x340
[  132.560888]  ? lock_is_held_type+0xe9/0x140
[  132.561660]  uart_port_activate+0x7f/0xe0
[  132.562351]  ? uart_startup.part.18+0x340/0x340
[  132.563003]  tty_port_open+0x8d/0xf0
[  132.563523]  ? uart_set_options+0x1e0/0x1e0
[  132.564125]  uart_open+0x24/0x40
[  132.564604]  tty_open+0x15c/0x630

Signed-off-by: Zheyu Ma 
Link: https://lore.kernel.org/r/1626242003-3809-1-git-send-email-zheyuma97@gmail.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: Fix data race between tiocsti() and flush_to_ldisc()

2021-09-22T09:41:22+00:00

commit bb2853a6a421a052268eee00fd5d3f6b3504b2b1 upstream.

The ops->receive_buf() may be accessed concurrently from these two
functions.  If the driver flushes data to the line discipline
receive_buf() method while tiocsti() is waiting for the
ops->receive_buf() to finish its work, the data race will happen.

For example:
tty_ioctl			|tty_ldisc_receive_buf
 ->tioctsi			| ->tty_port_default_receive_buf
				|  ->tty_ldisc_receive_buf
   ->hci_uart_tty_receive	|   ->hci_uart_tty_receive
    ->h4_recv                   |    ->h4_recv

In this case, the h4 receive buffer will be overwritten by the
latecomer, and we will lost the data.

Hence, change tioctsi() function to use the exclusive lock interface
from tty_buffer to avoid the data race.

Reported-by: syzbot+97388eb9d31b997fe1d0@syzkaller.appspotmail.com
Reviewed-by: Jiri Slaby 
Signed-off-by: Nguyen Dinh Phi 
Link: https://lore.kernel.org/r/20210823000641.2082292-1-phind.uet@gmail.com
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

vt_kdsetmode: extend console locking

2021-09-03T07:43:08+00:00

commit 2287a51ba822384834dafc1c798453375d1107c7 upstream.

As per the long-suffering comment.

Reported-by: Minh Yuan 
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

serial: 8250: Mask out floating 16/32-bit bus bits

2021-08-15T10:59:56+00:00

commit e5227c51090e165db4b48dcaa300605bfced7014 upstream.

Make sure only actual 8 bits of the IIR register are used in determining
the port type in `autoconfig'.

The `serial_in' port accessor returns the `unsigned int' type, meaning
that with UPIO_AU, UPIO_MEM16, UPIO_MEM32, and UPIO_MEM32BE access types
more than 8 bits of data are returned, of which the high order bits will
often come from bus lines that are left floating in the data phase.  For
example with the MIPS Malta board's CBUS UART, where the registers are
aligned on 8-byte boundaries and which uses 32-bit accesses, data as
follows is returned:

YAMON> dump -32 0xbf000900 0x40

BF000900: 1F000942 1F000942 1F000900 1F000900  ...B...B........
BF000910: 1F000901 1F000901 1F000900 1F000900  ................
BF000920: 1F000900 1F000900 1F000960 1F000960  ...........`...`
BF000930: 1F000900 1F000900 1F0009FF 1F0009FF  ................

YAMON>

Evidently high-order 24 bits return values previously driven in the
address phase (the 3 highest order address bits used with the command
above are masked out in the simple virtual address mapping used here and
come out at zeros on the external bus), a common scenario with bus lines
left floating, due to bus capacitance.

Consequently when the value of IIR, mapped at 0x1f000910, is retrieved
in `autoconfig', it comes out at 0x1f0009c1 and when it is right-shifted
by 6 and then assigned to 8-bit `scratch' variable, the value calculated
is 0x27, not one of 0, 1, 2, 3 expected in port type determination.

Fix the issue then, by assigning the value returned from `serial_in' to
`scratch' first, which masks out 24 high-order bits retrieved, and only
then right-shift the resulting 8-bit data quantity, producing the value
of 3 in this case, as expected.  Fix the same issue in `serial_dl_read'.

The problem first appeared with Linux 2.6.9-rc3 which predates our repo
history, but the origin could be identified with the old MIPS/Linux repo
also at: 
as commit e0d2356c0777 ("Merge with Linux 2.6.9-rc3."), where code in
`serial_in' was updated with this case:

+	case UPIO_MEM32:
+		return readl(up->port.membase + offset);
+

which made it produce results outside the unsigned 8-bit range for the
first time, though obviously it is system dependent what actual values
appear in the high order bits retrieved and it may well have been zeros
in the relevant positions with the system the change originally was
intended for.  It is at that point that code in `autoconf' should have
been updated accordingly, but clearly it was overlooked.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org # v2.6.12+
Reviewed-by: Philippe Mathieu-Daudé 
Signed-off-by: Maciej W. Rozycki 
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2106260516220.37803@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman