linux-toradex.git/drivers/tty, branch v4.9.113

vt: prevent leaking uninitialized data to userspace via /dev/vcs*

2018-07-11T14:26:42+00:00

commit 21eff69aaaa0e766ca0ce445b477698dc6a9f55a upstream.

KMSAN reported an infoleak when reading from /dev/vcs*:

  BUG: KMSAN: kernel-infoleak in vcs_read+0x18ba/0x1cc0
  Call Trace:
  ...
   kmsan_copy_to_user+0x7a/0x160 mm/kmsan/kmsan.c:1253
   copy_to_user ./include/linux/uaccess.h:184
   vcs_read+0x18ba/0x1cc0 drivers/tty/vt/vc_screen.c:352
   __vfs_read+0x1b2/0x9d0 fs/read_write.c:416
   vfs_read+0x36c/0x6b0 fs/read_write.c:452
  ...
  Uninit was created at:
   kmsan_save_stack_with_flags mm/kmsan/kmsan.c:279
   kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:189
   kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:315
   __kmalloc+0x13a/0x350 mm/slub.c:3818
   kmalloc ./include/linux/slab.h:517
   vc_allocate+0x438/0x800 drivers/tty/vt/vt.c:787
   con_install+0x8c/0x640 drivers/tty/vt/vt.c:2880
   tty_driver_install_tty drivers/tty/tty_io.c:1224
   tty_init_dev+0x1b5/0x1020 drivers/tty/tty_io.c:1324
   tty_open_by_driver drivers/tty/tty_io.c:1959
   tty_open+0x17b4/0x2ed0 drivers/tty/tty_io.c:2007
   chrdev_open+0xc25/0xd90 fs/char_dev.c:417
   do_dentry_open+0xccc/0x1440 fs/open.c:794
   vfs_open+0x1b6/0x2f0 fs/open.c:908
  ...
  Bytes 0-79 of 240 are uninitialized

Consistently allocating |vc_screenbuf| with kzalloc() fixes the problem

Reported-by: syzbot+17a8efdf800000@syzkaller.appspotmail.com
Signed-off-by: Alexander Potapenko 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

n_tty: Access echo_* variables carefully.

2018-07-11T14:26:41+00:00

commit ebec3f8f5271139df618ebdf8427e24ba102ba94 upstream.

syzbot is reporting stalls at __process_echoes() [1]. This is because
since ldata->echo_commit < ldata->echo_tail becomes true for some reason,
the discard loop is serving as almost infinite loop. This patch tries to
avoid falling into ldata->echo_commit < ldata->echo_tail situation by
making access to echo_* variables more carefully.

Since reset_buffer_flags() is called without output_lock held, it should
not touch echo_* variables. And omit a call to reset_buffer_flags() from
n_tty_open() by using vzalloc().

Since add_echo_byte() is called without output_lock held, it needs memory
barrier between storing into echo_buf[] and incrementing echo_head counter.
echo_buf() needs corresponding memory barrier before reading echo_buf[].
Lack of handling the possibility of not-yet-stored multi-byte operation
might be the reason of falling into ldata->echo_commit < ldata->echo_tail
situation, for if I do WARN_ON(ldata->echo_commit == tail + 1) prior to
echo_buf(ldata, tail + 1), the WARN_ON() fires.

Also, explicitly masking with buffer for the former "while" loop, and
use ldata->echo_commit > tail for the latter "while" loop.

[1] https://syzkaller.appspot.com/bug?id=17f23b094cd80df750e5b0f8982c521ee6bcbf40

Signed-off-by: Tetsuo Handa 
Reported-by: syzbot 
Cc: Peter Hurley 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

n_tty: Fix stall at n_tty_receive_char_special().

2018-07-11T14:26:41+00:00

commit 3d63b7e4ae0dc5e02d28ddd2fa1f945defc68d81 upstream.

syzbot is reporting stalls at n_tty_receive_char_special() [1]. This is
because comparison is not working as expected since ldata->read_head can
change at any moment. Mitigate this by explicitly masking with buffer size
when checking condition for "while" loops.

[1] https://syzkaller.appspot.com/bug?id=3d7481a346958d9469bebbeb0537d5f056bdd6e8

Signed-off-by: Tetsuo Handa 
Reported-by: syzbot 
Fixes: bc5a5e3f45d04784 ("n_tty: Don't wrap input buffer indices at buffer size")
Cc: stable 
Cc: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: Use spin_{try}lock_irqsave instead of open coding version

2018-07-03T09:23:06+00:00

commit 8afb1d2c12163f77777f84616a8e9444d0050ebe upstream.

Commit 40f70c03e33a ("serial: sh-sci: add locking to console write
function to avoid SMP lockup") copied the strategy to avoid locking
problems in conjuncture with the console from the UART8250
driver. Instead using directly spin_{try}lock_irqsave(),
local_irq_save() followed by spin_{try}lock() was used. While this is
correct on mainline, for -rt it is a problem. spin_{try}lock() will
check if it is running in a valid context. Since the local_irq_save()
has already been executed, the context has changed and
spin_{try}lock() will complain. The reason why spin_{try}lock()
complains is that on -rt the spin locks are turned into mutexes and
therefore can sleep. Sleeping with interrupts disabled is not valid.

BUG: sleeping function called from invalid context at /home/wagi/work/rt/v4.4-cip-rt/kernel/locking/rtmutex.c:995
in_atomic(): 0, irqs_disabled(): 128, pid: 778, name: irq/76-eth0
CPU: 0 PID: 778 Comm: irq/76-eth0 Not tainted 4.4.126-test-cip22-rt14-00403-gcd03665c8318 #12
Hardware name: Generic RZ/G1 (Flattened Device Tree)
Backtrace:
[] (dump_backtrace) from [] (show_stack+0x18/0x1c)
 r7:c06b01f0 r6:60010193 r5:00000000 r4:c06b01f0
[] (show_stack) from [] (dump_stack+0x78/0x94)
[] (dump_stack) from [] (___might_sleep+0x134/0x194)
 r7:60010113 r6:c06d3559 r5:00000000 r4:ffffe000
[] (___might_sleep) from [] (rt_spin_lock+0x20/0x74)
 r5:c06f4d60 r4:c06f4d60
[] (rt_spin_lock) from [] (serial_console_write+0x100/0x118)
 r5:c06f4d60 r4:c06f4d60
[] (serial_console_write) from [] (call_console_drivers.constprop.15+0x10c/0x124)
 r10:c06d2894 r9:c04e18b0 r8:00000028 r7:00000000 r6:c06d3559 r5:c06d2798
 r4:c06b9914 r3:c02576e4
[] (call_console_drivers.constprop.15) from [] (console_unlock+0x32c/0x430)
 r10:c06d30d8 r9:00000028 r8:c06dd518 r7:00000005 r6:00000000 r5:c06d2798
 r4:c06d2798 r3:00000028
[] (console_unlock) from [] (vprintk_emit+0x394/0x4f0)
 r10:c06d2798 r9:c06d30ee r8:00000006 r7:00000005 r6:c06a78fc r5:00000027
 r4:00000003
[] (vprintk_emit) from [] (vprintk+0x28/0x30)
 r10:c060bd46 r9:00001000 r8:c06b9a90 r7:c06b9a90 r6:c06b994c r5:c06b9a3c
 r4:c0062fa8
[] (vprintk) from [] (vprintk_default+0x10/0x14)
[] (vprintk_default) from [] (printk+0x78/0x84)
[] (printk) from [] (credit_entropy_bits+0x17c/0x2cc)
 r3:00000001 r2:decade60 r1:c061a5ee r0:c061a523
 r4:00000006
[] (credit_entropy_bits) from [] (add_interrupt_randomness+0x160/0x178)
 r10:466e7196 r9:1f536000 r8:fffeef74 r7:00000000 r6:c06b9a60 r5:c06b9a3c
 r4:dfbcf680
[] (add_interrupt_randomness) from [] (irq_thread+0x1e8/0x248)
 r10:c006537c r9:c06cdf21 r8:c0064fcc r7:df791c24 r6:df791c00 r5:ffffe000
 r4:df525180
[] (irq_thread) from [] (kthread+0x108/0x11c)
 r10:00000000 r9:00000000 r8:c0065184 r7:df791c00 r6:00000000 r5:df791d00
 r4:decac000
[] (kthread) from [] (ret_from_fork+0x14/0x3c)
 r8:00000000 r7:00000000 r6:00000000 r5:c003fa9c r4:df791d00

Cc: Sebastian Andrzej Siewior 
Signed-off-by: Daniel Wagner 
Reviewed-by: Geert Uytterhoeven 
Signed-off-by: Greg Kroah-Hartman

tty: pl011: Avoid spuriously stuck-off interrupts

2018-06-16T07:52:34+00:00

commit 4a7e625ce50412a7711efa0f2ef0b96ce3826759 upstream.

Commit 9b96fbacda34 ("serial: PL011: clear pending interrupts")
clears the RX and receive timeout interrupts on pl011 startup, to
avoid a screaming-interrupt scenario that can occur when the
firmware or bootloader leaves these interrupts asserted.

This has been noted as an issue when running Linux on qemu [1].

Unfortunately, the above fix seems to lead to potential
misbehaviour if the RX FIFO interrupt is asserted _non_ spuriously
on driver startup, if the RX FIFO is also already full to the
trigger level.

Clearing the RX FIFO interrupt does not change the FIFO fill level.
In this scenario, because the interrupt is now clear and because
the FIFO is already full to the trigger level, no new assertion of
the RX FIFO interrupt can occur unless the FIFO is drained back
below the trigger level.  This never occurs because the pl011
driver is waiting for an RX FIFO interrupt to tell it that there is
something to read, and does not read the FIFO at all until that
interrupt occurs.

Thus, simply clearing "spurious" interrupts on startup may be
misguided, since there is no way to be sure that the interrupts are
truly spurious, and things can go wrong if they are not.

This patch instead clears the interrupt condition by draining the
RX FIFO during UART startup, after clearing any potentially
spurious interrupt.  This should ensure that an interrupt will
definitely be asserted if the RX FIFO subsequently becomes
sufficiently full.

The drain is done at the point of enabling interrupts only.  This
means that it will occur any time the UART is newly opened through
the tty layer.  It will not apply to polled-mode use of the UART by
kgdboc: since that scenario cannot use interrupts by design, this
should not matter.  kgdboc will interact badly with "normal" use of
the UART in any case: this patch makes no attempt to paper over
such issues.

This patch does not attempt to address the case where the RX FIFO
fills faster than it can be drained: that is a pathological
hardware design problem that is beyond the scope of the driver to
work around.  As a failsafe, the number of poll iterations for
draining the FIFO is limited to twice the FIFO size.  This will
ensure that the kernel at least boots even if it is impossible to
drain the FIFO for some reason.

[1] [Qemu-devel] [Qemu-arm] [PATCH] pl011: do not put into fifo
before enabled the interruption
https://lists.gnu.org/archive/html/qemu-devel/2018-01/msg06446.html

Reported-by: Wei Xu 
Cc: Russell King 
Cc: Linus Walleij 
Cc: Peter Maydell 
Fixes: 9b96fbacda34 ("serial: PL011: clear pending interrupts")
Signed-off-by: Dave Martin 
Cc: stable 
Tested-by: Wei Xu 
Signed-off-by: Greg Kroah-Hartman

serial: 8250: omap: Fix idling of clocks for unused uarts

2018-06-16T07:52:34+00:00

commit 13dc04d0e5fdc25c8f713ad23fdce51cf2bf96ba upstream.

I noticed that unused UARTs won't necessarily idle properly always
unless at least one byte tx transfer is done first.

After some debugging I narrowed down the problem to the scr register
dma configuration bits that need to be set before softreset for the
clocks to idle. Unless we do this, the module clkctrl idlest bits
may be set to 1 instead of 3 meaning the clock will never idle and
is blocking deeper idle states for the whole domain.

This might be related to the configuration done by the bootloader
or kexec booting where certain configurations cause the 8250 or
the clkctrl clock to jam in a way where setting of the scr bits
and reset is needed to clear it. I've tried diffing the 8250
registers for the various modes, but did not see anything specific.
So far I've only seen this on omap4 but I'm suspecting this might
also happen on the other clkctrl using SoCs considering they
already have a quirk enabled for UART_ERRATA_CLOCK_DISABLE.

Let's fix the issue by configuring scr before reset for basic dma
even if we don't use it. The scr register will be reset when we do
softreset few lines after, and we restore scr on resume. We should
do this for all the SoCs with UART_ERRATA_CLOCK_DISABLE quirk flag
set since the ones with UART_ERRATA_CLOCK_DISABLE are all based
using clkctrl similar to omap4.

Looks like both OMAP_UART_SCR_DMAMODE_1 | OMAP_UART_SCR_DMAMODE_CTL
bits are needed for the clkctrl to idle after a softreset.

And we need to add omap4 to also use the UART_ERRATA_CLOCK_DISABLE
for the related workaround to be enabled. This same compatible
value will also be used for omap5.

Fixes: cdb929e4452a ("serial: 8250_omap: workaround errata around idling UART after using DMA")
Cc: Keerthy 
Cc: Matthijs van Duin 
Cc: Sekhar Nori 
Cc: Tero Kristo 
Signed-off-by: Tony Lindgren 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

serial: samsung: fix maxburst parameter for DMA transactions

2018-06-16T07:52:34+00:00

commit aa2f80e752c75e593b3820f42c416ed9458fa73e upstream.

The best granularity of residue that DMA engine can report is in the BURST
units, so the serial driver must use MAXBURST = 1 and DMA_SLAVE_BUSWIDTH_1_BYTE
if it relies on exact number of bytes transferred by DMA engine.

Fixes: 62c37eedb74c ("serial: samsung: add dma reqest/release functions")
Signed-off-by: Marek Szyprowski 
Acked-by: Krzysztof Kozlowski 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

tty/serial: atmel: use port->name as name in request_irq()

2018-06-16T07:52:34+00:00

commit 9594b5be7ec110ed11acec58fa94f3f293668c85 upstream.

I was puzzled while looking at /proc/interrupts and random things showed
up between reboots. This occurred more often but I realised it later. The
"correct" output should be:
|38:      11861  atmel-aic5   2 Level     ttyS0

but I saw sometimes
|38:       6426  atmel-aic5   2 Level     tty1

and accounted it wrongly as correct. This is use after free and the
former example randomly got the "old" pointer which pointed to the same
content. With SLAB_FREELIST_RANDOM and HARDENED I even got
|38:       7067  atmel-aic5   2 Level     E=Started User Manager for UID 0

or other nonsense.
As it turns out the tty, pointer that is accessed in atmel_startup(), is
freed() before atmel_shutdown(). It seems to happen quite often that the
tty for ttyS0 is allocated and freed while ->shutdown is not invoked. I
don't do anything special - just a systemd boot :)

Use dev_name(&pdev->dev) as the IRQ name for request_irq(). This exists
as long as the driver is loaded so no use-after-free here.

Cc: stable@vger.kernel.org
Fixes: 761ed4a94582 ("tty: serial_core: convert uart_close to use tty_port_close")
Acked-by: Richard Genoud 
Acked-by: Rob Herring 
Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: Stop using printk format %pCr

2018-06-16T07:52:33+00:00

commit d63c16f8e1ab761775275adcf54f4bef7c330295 upstream.

Printk format "%pCr" will be removed soon, as clk_get_rate() must not be
called in atomic context.

Replace it by open-coding the operation.  This is safe here, as the code
runs in task context.

Link: http://lkml.kernel.org/r/1527845302-12159-4-git-send-email-geert+renesas@glider.be
To: Jia-Ju Bai 
To: Jonathan Corbet 
To: Michael Turquette 
To: Stephen Boyd 
To: Zhang Rui 
To: Eduardo Valentin 
To: Eric Anholt 
To: Stefan Wahren 
To: Greg Kroah-Hartman 
Cc: Sergey Senozhatsky 
Cc: Petr Mladek 
Cc: Linus Torvalds 
Cc: Steven Rostedt 
Cc: linux-doc@vger.kernel.org
Cc: linux-clk@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: linux-serial@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-renesas-soc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Geert Uytterhoeven 
Cc: stable@vger.kernel.org # 4.5+
Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Petr Mladek 
Signed-off-by: Greg Kroah-Hartman

serial: pl011: add console matching function

2018-06-06T14:44:39+00:00

commit 10879ae5f12e9cab3c4e8e9504c1aaa8a033bde7 upstream.

This patch adds function pl011_console_match() that implements
method match of struct console.  It allows to match consoles against
data specified in a string, for example taken from command line or
compiled by ACPI SPCR table handler.

This patch was merged to tty-next but then reverted because of
conflict with

commit 46e36683f433 ("serial: earlycon: Extend earlycon command line option to support 64-bit addresses")

Now it is fixed.

Signed-off-by: Aleksey Makarov 
Reviewed-by: Peter Hurley 
Acked-by: Russell King 
Tested-by: Christopher Covington 
Signed-off-by: Ard Biesheuvel 
Signed-off-by: Greg Kroah-Hartman