commit 6798df4c5f upstream.
When csw->con_startup() fails in do_register_con_driver, we return no
error (i.e. 0). This was changed back in 2006 by commit 3e795de763.
Before that we used to return -ENODEV.
So fix the return value to be -ENODEV in that case again.
Fixes: 3e795de763 ("VT binding: Add binding/unbinding support for the VT console")
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: "Dan Carpenter" <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 0f40fbbcc3 upstream.
OpenSSH expects the (non-blocking) read() of pty master to return
EAGAIN only if it has received all of the slave-side output after
it has received SIGCHLD. This used to work on pre-3.12 kernels.
This fix effectively forces non-blocking read() and poll() to
block for parallel i/o to complete for all ttys. It also unwinds
these changes:
1) f8747d4a46
tty: Fix pty master read() after slave closes
2) 52bce7f8d4
pty, n_tty: Simplify input processing on final close
3) 1a48632ffe
pty: Fix input race when closing
Inspired by analysis and patch from Marc Aurele La France <tsi@tuyoix.net>
Reported-by: Volth <openssh@volth.com>
Reported-by: Marc Aurele La France <tsi@tuyoix.net>
BugLink: https://bugzilla.mindrot.org/show_bug.cgi?id=52
BugLink: https://bugzilla.mindrot.org/show_bug.cgi?id=2492
Signed-off-by: Brian Bloniarz <brian.bloniarz@gmail.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.16:
- No need to unwind commits 2 and 3
- Keep using tty_flush_to_ldisc() rather than adding tty_buffer_flush_work()]]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 2ce3c10c0c upstream.
This reverts commit c4dc304677.
This fix is superseded by commit 52bce7f8d4,
'pty, n_tty: Simplify input processing on final close'.
The final close now waits for input processing to complete before
destroying the pty, so poll() does not need to special case this
condition.
Cc: Francesco Ruggeri <fruggeri@arista.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit ff1cab374a upstream.
The BSP team noticed that there is spin/mutex lock issue on sh-sci when
CPUFREQ is used. The issue is that the notifier function may call
mutex_lock() while the spinlock is held, which can lead to a BUG().
This may happen if CPUFREQ is changed while another CPU calls
clk_get_rate().
Taking the spinlock was added to the notifier function in commit
e552de2413 ("sh-sci: add platform device private data"), to
protect the list of serial ports against modification during traversal.
At that time the Common Clock Framework didn't exist yet, and
clk_get_rate() just returned clk->rate without taking a mutex.
Note that since commit d535a2305f ("serial: sh-sci: Require a
device per port mapping."), there's no longer a list of serial ports to
traverse, and taking the spinlock became superfluous.
To fix the issue, just remove the cpufreq notifier:
1. The notifier doesn't work correctly: all it does is update the
stored clock rate; it does not update the divider in the hardware.
The divider will only be updated when calling sci_set_termios().
I believe this was broken back in 2004, when the old
drivers/char/sh-sci.c driver (where the notifier did update the
divider) was replaced by drivers/serial/sh-sci.c (where the
notifier just updated port->uartclk).
Cfr. full-history-linux commits 6f8deaef2e9675d9 ("[PATCH] sh: port
sh-sci driver to the new API") and 3f73fe878dc9210a ("[PATCH]
Remove old sh-sci driver").
2. On modern SoCs, the sh-sci parent clock rate is no longer related
to the CPU clock rate anyway, so using a cpufreq notifier is
futile.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 0b41ce9910 upstream.
Some UART HW has a single register combining UART_DLL/UART_DLM
(this was probably forgotten in the change that introduced the
callbacks, commit b32b19b8ff)
Fixes: b32b19b8ff ("[SERIAL] 8250: set divisor register correctly ...")
Signed-off-by: Sebastian Frias <sf84@laposte.net>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 1f55c718c2 upstream.
Considering current pty code and multiple devpts instances, it's possible
to umount a devpts file system while a program still has /dev/tty opened
pointing to a previosuly closed pty pair in that instance. In the case all
ptmx and pts/N files are closed, umount can be done. If the program closes
/dev/tty after umount is done, devpts_kill_index will use now an invalid
super_block, which was already destroyed in the umount operation after
running ->kill_sb. This is another "use after free" type of issue, but now
related to the allocated super_block instance.
To avoid the problem (warning at ida_remove and potential crashes) for
this specific case, I added two functions in devpts which grabs additional
references to the super_block, which pty code now uses so it makes sure
the super block structure is still valid until pty shutdown is done.
I also moved the additional inode references to the same functions, which
also covered similar case with inode being freed before /dev/tty final
close/shutdown.
Signed-off-by: Herton R. Krzesinski <herton@redhat.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 2831c89f42 upstream.
This change fixes a bug for a corner case where we have the the last
release from a pty master/slave coming from a previously opened /dev/tty
file. When this happens, the tty->driver_data can be stale, due to all
ptmx or pts/N files having already been closed before (and thus the inode
related to these files, which tty->driver_data points to, being already
freed/destroyed).
The fix here is to keep a reference on the opened master ptmx inode.
We maintain the inode referenced until the final pty_unix98_shutdown,
and only pass this inode to devpts_kill_index.
Signed-off-by: Herton R. Krzesinski <herton@redhat.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 308bbc9ab8 upstream.
The omap-serial driver emulates RS485 delays using software timers,
but neglects to clamp the input values from the unprivileged
ioctl(TIOCSRS485). Because the software implementation busy-waits,
malicious userspace could stall the cpu for ~49 days.
Clamp the input values to < 100ms.
Fixes: 4a0ac0f55b ("OMAP: add RS485 support")
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 6d27a63caa upstream.
Although n_tty_check_unthrottle() has a valid ldisc reference (since
the tty core gets the ldisc ref in tty_read() before calling the line
discipline read() method), it does not have a valid ldisc reference to
the "other" pty of a pty pair. Since getting an ldisc reference for
tty->link essentially open-codes tty_wakeup(), just replace with the
equivalent tty_wakeup().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 5c17c861a3 upstream.
ioctl(TIOCGETD) retrieves the line discipline id directly from the
ldisc because the line discipline id (c_line) in termios is untrustworthy;
userspace may have set termios via ioctl(TCSETS*) without actually
changing the line discipline via ioctl(TIOCSETD).
However, directly accessing the current ldisc via tty->ldisc is
unsafe; the ldisc ptr dereferenced may be stale if the line discipline
is changing via ioctl(TIOCSETD) or hangup.
Wait for the line discipline reference (just like read() or write())
to retrieve the "current" line discipline id.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Moritz Muehlenhoff <jmm@inutil.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 984cf355ae upstream.
Commit 984d74a720 ("sysrq: rcu-ify __handle_sysrq") replaced
spin_lock_irqsave() calls with rcu_read_lock() calls in sysrq. Since
rcu_read_lock() does not disable preemption, faulthandler_disabled() in
__do_page_fault() in x86/fault.c returns false. When the code later calls
might_sleep() in the pagefault handler, we get the following warning:
BUG: sleeping function called from invalid context at ../arch/x86/mm/fault.c:1187
in_atomic(): 0, irqs_disabled(): 0, pid: 4706, name: bash
Preemption disabled at:[<ffffffff81484339>] printk+0x48/0x4a
To fix this, we release the RCU read lock before we crash.
Tested this patch on linux 3.18 by booting off one of our boards.
Fixes: 984d74a720 ("sysrq: rcu-ify __handle_sysrq")
Signed-off-by: Ani Sinha <ani@arista.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit ac8f3bf883 upstream.
commit 40d5e0905a ("n_tty: Fix EOF push handling") fixed EOF push
for reads. However, that approach still allows a condition mismatch
between poll() and read(), where poll() returns POLLIN but read()
blocks. This state can happen when a previous read() returned because
the user buffer was full and the next character was an EOF not at the
beginning of the line. While the next read() will properly identify
the condition and advance the read buffer tail without improperly
indicating an EOF file condition (ie., read() will not mistakenly
return 0), poll() will mistakenly indicate POLLIN.
Although a possible solution would be to peek at the input buffer
in n_tty_poll(), the better solution in this patch is to eat the
EOF during the previous read() (ie., fix the problem by eliminating
the condition).
The current canon line buffer copy limits the scan for next end-of-line
to the smaller of either,
a. the remaining user buffer size
b. completed lines in the input buffer
When the remaining user buffer size is exactly one less than the
end-of-line marked by EOF push, the EOF is not scanned nor skipped
but left for subsequent reads. In the example below, the scan
index 'eol' has stopped at the EOF because it is past the scan
limit of 5 (not because it has found the next set bit in read_flags)
user buffer [*nr = 5] _ _ _ _ _
read_flags 0 0 0 0 0 1
input buffer h e l l o [EOF]
^ ^
/ /
tail eol
result: found = 0, tail += 5, *nr += 5
Instead, allow the scan to peek ahead 1 byte (while still limiting the
scan to completed lines in the input buffer). For the example above,
result: found = 1, tail += 6, *nr += 5
Because the scan limit is now bumped +1 byte, when the scan is
completed, the tail advance and the user buffer copy limit is
re-clamped to *nr when EOF is _not_ found.
Fixes: 40d5e0905a ("n_tty: Fix EOF push handling")
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit e81107d4c6 upstream.
My colleague ran into a program stall on a x86_64 server, where
n_tty_read() was waiting for data even if there was data in the buffer
in the pty. kernel stack for the stuck process looks like below.
#0 [ffff88303d107b58] __schedule at ffffffff815c4b20
#1 [ffff88303d107bd0] schedule at ffffffff815c513e
#2 [ffff88303d107bf0] schedule_timeout at ffffffff815c7818
#3 [ffff88303d107ca0] wait_woken at ffffffff81096bd2
#4 [ffff88303d107ce0] n_tty_read at ffffffff8136fa23
#5 [ffff88303d107dd0] tty_read at ffffffff81368013
#6 [ffff88303d107e20] __vfs_read at ffffffff811a3704
#7 [ffff88303d107ec0] vfs_read at ffffffff811a3a57
#8 [ffff88303d107f00] sys_read at ffffffff811a4306
#9 [ffff88303d107f50] entry_SYSCALL_64_fastpath at ffffffff815c86d7
There seems to be two problems causing this issue.
First, in drivers/tty/n_tty.c, __receive_buf() stores the data and
updates ldata->commit_head using smp_store_release() and then checks
the wait queue using waitqueue_active(). However, since there is no
memory barrier, __receive_buf() could return without calling
wake_up_interactive_poll(), and at the same time, n_tty_read() could
start to wait in wait_woken() as in the following chart.
__receive_buf() n_tty_read()
------------------------------------------------------------------------
if (waitqueue_active(&tty->read_wait))
/* Memory operations issued after the
RELEASE may be completed before the
RELEASE operation has completed */
add_wait_queue(&tty->read_wait, &wait);
...
if (!input_available_p(tty, 0)) {
smp_store_release(&ldata->commit_head,
ldata->read_head);
...
timeout = wait_woken(&wait,
TASK_INTERRUPTIBLE, timeout);
------------------------------------------------------------------------
The second problem is that n_tty_read() also lacks a memory barrier
call and could also cause __receive_buf() to return without calling
wake_up_interactive_poll(), and n_tty_read() to wait in wait_woken()
as in the chart below.
__receive_buf() n_tty_read()
------------------------------------------------------------------------
spin_lock_irqsave(&q->lock, flags);
/* from add_wait_queue() */
...
if (!input_available_p(tty, 0)) {
/* Memory operations issued after the
RELEASE may be completed before the
RELEASE operation has completed */
smp_store_release(&ldata->commit_head,
ldata->read_head);
if (waitqueue_active(&tty->read_wait))
__add_wait_queue(q, wait);
spin_unlock_irqrestore(&q->lock,flags);
/* from add_wait_queue() */
...
timeout = wait_woken(&wait,
TASK_INTERRUPTIBLE, timeout);
------------------------------------------------------------------------
There are also other places in drivers/tty/n_tty.c which have similar
calls to waitqueue_active(), so instead of adding many memory barrier
calls, this patch simply removes the call to waitqueue_active(),
leaving just wake_up*() behind.
This fixes both problems because, even though the memory access before
or after the spinlocks in both wake_up*() and add_wait_queue() can
sneak into the critical section, it cannot go past it and the critical
section assures that they will be serialized (please see "INTER-CPU
ACQUIRING BARRIER EFFECTS" in Documentation/memory-barriers.txt for a
better explanation). Moreover, the resulting code is much simpler.
Latency measurement using a ping-pong test over a pty doesn't show any
visible performance drop.
Signed-off-by: Kosuke Tatsukawa <tatsu@ab.jp.nec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ luis: backported to 3.16:
- always use wake_up_interruptible() instead of wake_up_interruptible_poll()
- adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 899f0c1c7d upstream.
The internal clock of the master chip, which is usually 125MHz, is only half
(62.5MHz) for the slave chips. So we have to adjust the uartclk for all the
slave ports. Therefor we add a new function to determine if a slave chip is
present and update pci_xr17v35x_setup accordingly.
Signed-off-by: Soeren Grunewald <soeren.grunewald@desy.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit be32c0cf04 upstream.
The Exar XR17V358 can also be combined with a XR17V354 chip to act as a
single 12 port chip. This works the same way as the combining two XR17V358
chips. But the reported device id then is 0x4358.
Signed-off-by: Soeren Grunewald <soeren.grunewald@desy.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 96a5d18bc1 upstream.
The Exar XR17V358 chip usually provides only 8 ports. But two chips can be
combined to act as a single 16 port chip. Therefor one chip is configured
as master the second as slave by connecting the mode pin to VCC (master)
or GND (slave).
Then the master chip is reporting a different device-id depending on
whether a slave is detected or not. The UARTs 8-15 are addressed from
0x2000-0x3fff. So the offset of 0x400 from UART to UART can be used to
address all 16 ports as before.
See: https://www.exar.com/common/content/document.ashx?id=1587 page 11
Signed-off-by: Soeren Grunewald <soeren.grunewald@desy.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit ffa34de03b upstream.
SMSC IrCC SIR/FIR port should not be bound to by
(legacy) serial driver so its own driver (smsc-ircc2)
can bind to it.
Signed-off-by: Maciej Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit abab381fee upstream.
The platform_sysrq_reset_seq code was intended as a way for an embedded
platform to provide its own sysrq sequence at compile time. After over
two years, nobody has started using it in an upstream kernel, and
the platforms that were interested in it have moved on to devicetree,
which can be used to configure the sequence without requiring kernel
changes. The method is also incompatible with the way that most
architectures build support for multiple platforms into a single
kernel.
Now the code is producing warnings when built with gcc-5.1:
drivers/tty/sysrq.c: In function 'sysrq_init':
drivers/tty/sysrq.c:959:33: warning: array subscript is above array bounds [-Warray-bounds]
key = platform_sysrq_reset_seq[i];
We could fix this, but it seems unlikely that it will ever be used,
so let's just remove the code instead. We still have the option to
pass the sequence either in DT, using the kernel command line,
or using the /sys/module/sysrq/parameters/reset_seq file.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 154b7a489a ("Input: sysrq - allow specifying alternate reset sequence")
----
v2: moved sysrq_reset_downtime_ms variable to avoid introducing a compile
warning when CONFIG_INPUT is disabled
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 72586c6061 upstream.
Commit 32f13521ca
("n_tty: Line copy to user buffer in canonical mode")
changed cannonical mode copying to use copy_to_user
but missed adding the call to the audit framework.
Add in the appropriate functions to get audit support.
Fixes: 32f13521ca ("n_tty: Line copy to user buffer in canonical mode")
Reported-by: Miloslav Trmač <mitr@redhat.com>
Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 392bceedb1 upstream.
The driver configures the IDLE condition to interrupt the SDMA engine.
Since the SDMA UART ROM script doesn't clear the IDLE bit itself, this
caused repeated 1-byte DMA transfers, regardless of available data in the
RX FIFO. Also, when returning due to the IDLE condition, the UART ROM
script already increased its counter, causing residue to be off by one.
This patch clears the IDLE condition to avoid repeated 1-byte DMA transfers
and decreases count by when the DMA transfer was aborted due to the IDLE
condition, fixing serial transfers using DMA on i.MX6Q.
Reported-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 77bb3dfdc0 upstream.
A non-percpu VIRQ (e.g., VIRQ_CONSOLE) may be freed on a different
VCPU than it is bound to. This can result in a race between
handle_percpu_irq() and removing the action in __free_irq() because
handle_percpu_irq() does not take desc->lock. The interrupt handler
sees a NULL action and oopses.
Only use the percpu chip/handler for per-CPU VIRQs (like VIRQ_TIMER).
# cat /proc/interrupts | grep virq
40: 87246 0 xen-percpu-virq timer0
44: 0 0 xen-percpu-virq debug0
47: 0 20995 xen-percpu-virq timer1
51: 0 0 xen-percpu-virq debug1
69: 0 0 xen-dyn-virq xen-pcpu
74: 0 0 xen-dyn-virq mce
75: 29 0 xen-dyn-virq hvc_console
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 8f9cfeed3e upstream.
when gsmtty_remove put dlci, it will cause memory leak if dlci->port's refcount is zero.
So we do the cleanup work in .cleanup callback instead.
dlci will be last put in two call chains.
1) gsmld_close -> gsm_cleanup_mux -> gsm_dlci_release -> dlci_put
2) gsmld_remove -> dlci_put
so there is a race. the memory leak depends on the race.
In call chain 2. we hit the memory leak. below comment tells.
release_tty -> tty_driver_remove_tty -> gsmtty_remove -> dlci_put -> tty_port_destructor (WARN_ON(port->itty) and return directly)
|
tty->port->itty = NULL;
|
tty_kref_put ---> release_one_tty -> gsmtty_cleanup (added by our patch)
So our patch fix the memory leak by doing the cleanup work after tty core did.
Signed-off-by: Pan Xinhui <xinhuix.pan@intel.com>
Fixes: dfabf7ffa3
Acked-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit b9d934f27c upstream.
After a resume the hypervisor/tools may change console event
channel number. We should re-query it.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit a8d4e01637 upstream.
Maxburst was not set when doing the dma slave configuration. This value
is checked by the recently introduced xdmac. It causes an error when
doing the slave configuration and so prevents from using dma.
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 6befa9d883 upstream.
Do not probe all serial drivers by of_serial.c which are using
device_type = "serial"; property. Only drivers which have valid
compatible strings listed in the driver should be probed.
When PORT_UNKNOWN is setup probe will fail anyway.
Arnd quotation about driver historical background:
"when I wrote that driver initially, the idea was that it would
get used as a stub to hook up all other serial drivers but after
that, the common code learned to create platform devices from DT"
This patch fix the problem with on the system with xilinx_uartps and
16550a where of_serial failed to register for xilinx_uartps and because
of irq_dispose_mapping() removed irq_desc. Then when xilinx_uartps was asking
for irq with request_irq() EINVAL is returned.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 5c90c07b98 upstream.
For systems with CONFIG_SERIAL_OF_PLATFORM=y and device_type =
"serial"; property in DT of_serial.c driver maps and unmaps IRQ (because
driver probe fails). Then a driver is called but irq mapping is not
created that's why driver is failing again in again on request_irq().
Based on this use platform_get_irq() instead of platform_get_resource()
which is doing irq_desc allocation and driver itself can request IRQ.
Fix both xilinx serial drivers in the tree.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit fb5ef9e7da upstream.
In canon mode, the read buffer head will advance over the buffer tail
if the input > 4095 bytes without receiving a line termination char.
Discard additional input until a line termination is received.
Before evaluating for overflow, the 'room' value is normalized for
I_PARMRK and 1 byte is reserved for line termination (even in !icanon
mode, in case the mode is switched). The following table shows the
transform:
actual buffer | 'room' value before overflow calc
space avail | !I_PARMRK | I_PARMRK
--------------------------------------------------
0 | -1 | -1
1 | 0 | 0
2 | 1 | 0
3 | 2 | 0
4+ | 3 | 1
When !icanon or when icanon and the read buffer contains newlines,
normalized 'room' values of -1 and 0 are clamped to 0, and
'overflow' is 0, so read_head is not adjusted and the input i/o loop
exits (setting no_room if called from flush_to_ldisc()). No input
is discarded since the reader does have input available to read
which ensures forward progress.
When icanon and the read buffer does not contain newlines and the
normalized 'room' value is 0, then overflow and room are reset to 1,
so that the i/o loop will process the next input char normally
(except for parity errors which are ignored). Thus, erasures, signalling
chars, 7-bit mode, etc. will continue to be handled properly.
If the input char processed was not a line termination char, then
the canon_head index will not have advanced, so the normalized 'room'
value will now be -1 and 'overflow' will be set, which indicates the
read_head can safely be reset, effectively erasing the last char
processed.
If the input char processed was a line termination, then the
canon_head index will have advanced, so 'overflow' is cleared to 0,
the read_head is not reset, and 'room' is cleared to 0, which exits
the i/o loop (because the reader now have input available to read
which ensures forward progress).
Note that it is possible for a line termination to be received, and
for the reader to copy the line to the user buffer before the
input i/o loop is ready to process the next input char. This is
why the i/o loop recomputes the room/overflow state with every
input char while handling overflow.
Finally, if the input data was processed without receiving
a line termination (so that overflow is still set), the pty
driver must receive a write wakeup. A pty writer may be waiting
to write more data in n_tty_write() but without unthrottling
here that wakeup will not arrive, and forward progress will halt.
(Normally, the pty writer is woken when the reader reads data out
of the buffer and more space become available).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 8e4934c6d6 upstream.
When the receiver was enabled during startup, a character could
have been in the FIFO when the UART get initially used. The
driver configures the (receive) watermark level, and flushes the
FIFO. However, the receive flag (RDRF) could still be set at that
stage (as mentioned in the register description of UARTx_RWFIFO).
This leads to an interrupt which won't be handled properly in
interrupt mode: The receive interrupt function lpuart_rxint checks
the FIFO count, which is 0 at that point (due to the flush
during initialization). The problem does not manifest when using
DMA to receive characters.
Fix this situation by explicitly read the status register, which
leads to clearing of the RDRF flag. Due to the flush just after
the status flag read, a explicit data read is not to required.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 7fd6f640f2 upstream.
Trying to write console output from within the serial console driver
while the port->lock is held causes recursive deadlock:
CPU 0
spin_lock_irqsave(&port->lock)
printk()
console_unlock()
call_console_drivers()
serial8250_console_write()
spin_lock_irqsave(&port->lock)
** DEADLOCK **
The 8250_dw i/o accessors try to write a console error message if the
LCR workaround was unsuccessful. When the port->lock is already held
(eg., when called from serial8250_set_termios()), this deadlocks.
Make the error message a FIXME until a general solution is devised.
Cc: Tim Kryger <tim.kryger@gmail.com>
Reported-by: Zhang Zhen <zhenzhang.zhang@huawei.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ luis: backported to 3.16:
- dropped changes to dw8250_serial_outq() ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 79fbf4a550 upstream.
Fix overflow bug in tty_wait_until_sent on 64-bit machines, where an
infinite timeout (0) would be passed to the underlying tty-driver's
wait_until_sent-operation as a negative timeout (-1), causing it to
return immediately.
This manifests itself for example as tcdrain() returning immediately,
drivers not honouring the drain flags when setting terminal attributes,
or even dropped data on close as a requested infinite closing-wait
timeout would be ignored.
The first symptom was reported by Asier LLANO who noted that tcdrain()
returned prematurely when using the ftdi_sio usb-serial driver.
Fix this by passing 0 rather than MAX_SCHEDULE_TIMEOUT (LONG_MAX) to the
underlying tty driver.
Note that the serial-core wait_until_sent-implementation is not affected
by this bug due to a lucky chance (comparison to an unsigned maximum
timeout), and neither is the cyclades one that had an explicit check for
negative timeouts, but all other tty drivers appear to be affected.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: ZIV-Asier Llano Palacios <asier.llano@cgglobal.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit f0bf0bd079 upstream.
This problem was taken care of three times already in
* b0de59b573 (TTY: do not update
atime/mtime on read/write),
* 37b7f3c765 (TTY: fix atime/mtime
regression), and
* b0b885657b (tty: fix up atime/mtime
mess, take three)
But it still misses one point. As John Paul correctly points out, we
do not care about setting date. If somebody ever changes wall
time backwards (by mistake for example), tty timestamps are never
updated until the original wall time passes.
So check the absolute difference of times and if it large than "8
seconds or so", always update the time. That means we will update
immediatelly when changing time. Ergo, CAP_SYS_TIME can foul the
check, but it was always that way.
Thanks John for serving me this so nicely debugged.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: John Paul Perry <john_paul.perry@alcatel-lucent.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit f2e0ea8611 upstream.
I'm still receiving reports to my email address, so let's point this
at the linux-serial mailing list instead.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 5f1437f61a upstream.
When the UART is in DMA receive mode (RDMAS set) and one character
just arrived while another interrupt is handled (e.g. TX), the RDRF
(receiver data register full flag) is set due to the water level of
1. But since the DMA will take care of this character, there is no
need to handle it by calling lpuart_prepare_rx. Handling it leads to
adding the RX timeout timer twice:
[ 74.336698] Kernel BUG at 80053070 [verbose debug info unavailable]
[ 74.342999] Internal error: Oops - BUG: 0 [#1] ARM0:00.00 khungtaskd
[ 74.347817] Modules linked in: 0 S 0.0 0.0 0:00.00 writeback
[ 74.350926] CPU: 0 PID: 0 Comm: swapper Not tainted 3.19.0-rc3-00001-g39d78e2 #1788
[ 74.358617] Hardware name: Freescale Vybrid VF610 (Device Tree)t
[ 74.364563] task: 807a7678 ti: 8079c000 task.ti: 8079c000 kblockd
[ 74.370002] PC is at add_timer+0x24/0x28.0 0.0 0:00.09 kworker/u2:1
[ 74.373960] LR is at lpuart_int+0x15c/0x3d8
[ 74.378171] pc : [<80053070>] lr : [<802e0d88>] psr: a0010193
[ 74.378171] sp : 8079de10 ip : 8079de20 fp : 8079de1c
[ 74.389694] r10: 807d44c0 r9 : 8688c300 r8 : 00000013
[ 74.394943] r7 : 20010193 r6 : 00000000 r5 : 000000a0 r4 : 86997210
[ 74.401498] r3 : ffffa7da r2 : 80817868 r1 : 86997210 r0 : 86997344
[ 74.408052] Flags: NzCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel
[ 74.415489] Control: 10c5387d Table: 8611c059 DAC: 00000015
[ 74.421265] Process swapper (pid: 0, stack limit = 0x8079c230)
...
Solve this by only execute the receiver path (lpuart_prepare_rx) if
the DMA receive mode (RDMAS) is not set. Also, make sure the flag is
cleared on initialization, in case it has been left set.
This can be best reproduced using UART as a serial console, then
running top while dd'ing data into the terminal.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 4a8588a1cf upstream.
If the serial port gets closed while a RX transfer is in progress,
the timer might fire after the serial port shutdown finished. This
leads in a NULL pointer dereference:
[ 7.508324] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[ 7.516590] pgd = 86348000
[ 7.519445] [00000000] *pgd=86179831, *pte=00000000, *ppte=00000000
[ 7.526145] Internal error: Oops: 17 [#1] ARM
[ 7.530611] Modules linked in:
[ 7.533876] CPU: 0 PID: 123 Comm: systemd Not tainted 3.19.0-rc3-00004-g5b11ea7 #1778
[ 7.541827] Hardware name: Freescale Vybrid VF610 (Device Tree)
[ 7.547862] task: 861c3400 ti: 86ac8000 task.ti: 86ac8000
[ 7.553392] PC is at lpuart_timer_func+0x24/0xf8
[ 7.558127] LR is at lpuart_timer_func+0x20/0xf8
[ 7.562857] pc : [<802df99c>] lr : [<802df998>] psr: 600b0113
[ 7.562857] sp : 86ac9b90 ip : 86ac9b90 fp : 86ac9bbc
[ 7.574467] r10: 80817180 r9 : 80817b98 r8 : 80817998
[ 7.579803] r7 : 807acee0 r6 : 86989000 r5 : 00000100 r4 : 86997210
[ 7.586444] r3 : 86ac8000 r2 : 86ac9bc0 r1 : 86997210 r0 : 00000000
[ 7.593085] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
[ 7.600341] Control: 10c5387d Table: 86348059 DAC: 00000015
[ 7.606203] Process systemd (pid: 123, stack limit = 0x86ac8230)
Setup the timer on UART startup which allows to delete the timer
unconditionally on shutdown. This also saves the initialization
on each transfer.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 37480a0568 upstream.
Commit 26df6d1340 ("tty: Add EXTPROC support for LINEMODE")
allows a process which has opened a pty master to send _any_ signal
to the process group of the pty slave. Although potentially
exploitable by a malicious program running a setuid program on
a pty slave, it's unknown if this exploit currently exists.
Limit to signals actually used.
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Howard Chu <hyc@symas.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 19e3ae6b4f upstream.
The vcs device's poll/fasync support relies on the vt notifier to signal
changes to the screen content. Notifier invocations were missing for
changes that comes through the selection interface though. Fix that.
Tested with BRLTTY 5.2.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Cc: Dave Mielke <dave@mielke.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 6fbb9bdf0f upstream.
-EDEFER error wasn't handle properly by atmel_serial_probe().
As an example, when atmel_serial_probe() is called for the first time, we pass
the test_and_set_bit() test to check whether the port has already been
initalized. Then we call atmel_init_port(), which may return -EDEFER, possibly
returned before by clk_get(). Consequently atmel_serial_probe() used to return
this error code WITHOUT clearing the port bit in the "atmel_ports_in_use" mask.
When atmel_serial_probe() was called for the second time, it used to fail on
the test_and_set_bit() function then returning -EBUSY.
When atmel_serial_probe() fails, this patch make it clear the port bit in the
"atmel_ports_in_use" mask, if needed, before returning the error code.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit d4f641876a upstream.
atmel_serial_probe() calls atmel_init_port(). In turn, atmel_init_port() calls
clk_disable_unprepare() to disable the peripheral clock before returning.
Later atmel_serial_probe() accesses some I/O registers such as the Mode and
Control registers for RS485 support then the Name and Version registers, through a call to
atmel_get_ip_name(), but at that moment the peripheral clock was still
disabled.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit c4dc304677 upstream.
Commit f95499c303 ("n_tty: Don't wait for buffer work in read() loop")
introduces a race window where a pty master can be signalled that the pty
slave was closed before all the data that the slave wrote is delivered.
Commit f8747d4a46 ("tty: Fix pty master read() after slave closes") fixed the
problem in case of n_tty_read, but the problem still exists for n_tty_poll.
This can be seen by running 'for ((i=0; i<100;i++));do ./test.py ;done'
where test.py is:
import os, select, pty
(pid, pty_fd) = pty.fork()
if pid == 0:
os.write(1, 'This string should be received by parent')
else:
poller = select.epoll()
poller.register( pty_fd, select.EPOLLIN )
ready = poller.poll( 1 * 1000 )
for fd, events in ready:
if not events & select.EPOLLIN:
print 'missed POLLIN event'
else:
print os.read(fd, 100)
poller.close()
The string from the slave is missed several times.
This patch takes the same approach as the fix for read and special cases
this condition for poll.
Tested on 3.16.
Signed-off-by: Francesco Ruggeri <fruggeri@arista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 8bfbe2de76 upstream.
Commit 19e2ad6a09 ("n_tty: Remove overflow
tests from receive_buf() path") moved the increment of read_head into
the arguments list of read_buf_addr(). Function calls represent a
sequence point in C. Therefore read_head is incremented before the
character c is placed in the buffer. Since the circular read buffer is
a lock-less design since commit 6d76bd2618
("n_tty: Make N_TTY ldisc receive path lockless"), this creates a race
condition that leads to communication errors.
This patch modifies the code to increment read_head _after_ the data
is placed in the buffer and thus fixes the race for non-SMP machines.
To fix the problem for SMP machines, memory barriers must be added in
a separate patch.
Signed-off-by: Christian Riesch <christian.riesch@omicron.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 1ff383a4c3 upstream.
This patch adds waiting until transmit buffer and shifter will be empty
before clock disabling.
Without this fix it's possible to have clock disabled while data was
not transmited yet, which causes unproper state of TX line and problems
in following data transfers.
Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 6b1f40cf48 upstream.
The mcb_device_id table is supposed to be zero-terminated.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 8b37439946 upstream.
Frank reports that after continuing in kgdb the RX stale event
doesn't occur until after the RX fifo is filled up with exactly
the amount of characters programmed for the RX watermark (in this
case it's 48). To read a single character from the uartdm
hardware we force a stale event so that any characters in the RX
packing buffer are flushed into the RX fifo immediately instead
of waiting for a stale timeout or for the fifo to fill. Forcing
that stale event asserts the stale interrupt but we never clear
that interrupt via UART_CR_CMD_RESET_STALE_INT in the polling
functions. So when kgdb continues the stale interrupt is left
pending in the hardware and we don't timeout with a stale event,
like we usually would if a user typed one character on the
console, until the reset stale interrupt and stale event commands
are sent. Frank could get things working again by running
handle_rx_dm(). By putting enough characters into the fifo he
could trigger a watermark interrupt, and thus cause
handle_rx_dm() to run finally resetting the stale interrupt
and enabling the stale event so that single characters would
cause timeouts again.
The fix is to just do what the interrupt routine was doing all
along and clear the stale interrupt and enable the event again.
Doing this also smooths over any differences in the fifo behavior
between v1.3 and v1.4 hardware allowing us to skip forcing the
uart into single character mode.
Reviewed-by: Frank Rowand <frank.rowand@sonymobile.com>
Tested-by: Frank Rowand <frank.rowand@sonymobile.com>
Fixes: f7e54d7ad7 "msm_serial: Add support for poll_{get,put}_char()"
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 9e326f7871 upstream.
We can call this function for a dummy console that doesn't support
setting the font mapping, which will result in a null ptr BUG. So check
for this case and return error for consoles w/o font mapping support.
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=59321
Signed-off-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 494c1eac7e upstream.
Only print one warning when a task is on the read_wait or write_wait
wait queue at final tty release.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 37b1645788 upstream.
Kernel oops can cause the tty to be unreleaseable (for example, if
n_tty_read() crashes while on the read_wait queue). This will cause
tty_release() to endlessly loop without sleeping.
Use a killable sleep timeout which grows by 2n+1 jiffies over the interval
[0, 120 secs.) and then jumps to forever (but still killable).
NB: killable just allows for the task to be rewoken manually, not
to be terminated.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 547039ec50 upstream.
uart_get_baud_rate() will return baud == 0 if the max rate is set
to the "magic" 38400 rate and the SPD_* flags are also specified.
On the first iteration, if the current baud rate is higher than the
max, the baud rate is clamped at the max (which in the degenerate
case is 38400). On the second iteration, the now-"magic" 38400 baud
rate selects the possibly higher alternate baud rate indicated by
the SPD_* flag. Since only two loop iterations are performed, the
loop is exited, a kernel WARNING is generated and a baud rate of
0 is returned.
Reproducible with:
setserial /dev/ttyS0 spd_hi base_baud 38400
Only perform the "magic" 38400 -> SPD_* baud transform on the first
loop iteration, which prevents the degenerate case from recognizing
the clamped baud rate as the "magic" 38400 value.
Reported-by: Robert Święcki <robert@swiecki.net>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
