21 Nov, 2015
1 commit
-
The data to audit/record is in the 'from' buffer (ie., the input
read buffer).Fixes: 72586c6061ab ("n_tty: Fix auditing support for cannonical mode")
Cc: stable # 4.1+
Cc: Miloslav Trmač
Signed-off-by: Peter Hurley
Acked-by: Laura Abbott
Signed-off-by: Greg Kroah-Hartman
18 Oct, 2015
5 commits
-
Introduce API functions to restart and cancel tty buffer work, rather
than manipulate buffer work directly.Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
The job_control() check in n_tty_read() has nearly identical purpose
and results as tty_check_change(). Both functions' purpose is to
determine if the current task's pgrp is the foreground pgrp for the tty,
and if not, to signal the current pgrp.Introduce __tty_check_change() which takes the signal to send
and performs the shared operations for job control() and
tty_check_change().Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
In-tree users of wait_event_interruptible_tty() have been removed;
remove.Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
With the removal of tty_wait_until_sent_from_close(), tty drivers
no longer wait during open for parallel closes to complete (instead,
the tty core waits before calling the driver open() method). Thus,
the close_wait waitqueue is no longer used for waiting.Remove struct tty_port::close_wait.
Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
tty_wait_until_sent_from_close() drops the tty lock while waiting
for the tty driver to finish sending previously accepted data (ie.,
data remaining in its write buffer and transmit fifo).tty_wait_until_sent_from_close() was added by commit a57a7bf3fc7e
("TTY: define tty_wait_until_sent_from_close") to prevent the entire
tty subsystem from being unable to open new ttys while waiting for
one tty to close while output drained.However, since commit 0911261d4cb6 ("tty: Don't take tty_mutex for tty
count changes"), holding a tty lock while closing does not prevent other
ttys from being opened/closed/hung up, but only prevents lifetime event
changes for the tty under lock.Holding the tty lock while waiting for output to drain does prevent
parallel non-blocking opens (O_NONBLOCK) from advancing or returning
while the tty lock is held. However, all parallel opens _already_
block even if the tty lock is dropped while closing and the parallel
open advances. Blocking in open has been in mainline since at least 2.6.29
(see tty_port_block_til_ready(); note the test for O_NONBLOCK is _after_
the wait while ASYNC_CLOSING).IOW, before this patch a non-blocking open will sleep anyway for the
_entire_ duration of a parallel hardware shutdown, and when it wakes, the
error return will cause a release of its tty, and it will restart with
a fresh attempt to open. Similarly with a blocking open that is already
waiting; when it's woken, the hardware shutdown has already completed
to ASYNC_INITIALIZED is not set, which forces a release and restart as
well.So, holding the tty lock across the _entire_ close (which is what this
patch does), even while waiting for output to drain, is equivalent to
the current outcome wrt parallel opens.Cc: Alan Cox
Cc: David Laight
CC: Arnd Bergmann
CC: Karsten Keil
CC: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman
24 Jul, 2015
1 commit
-
Introduce tty_debug() macro to output uniform debug information for
tty core debug messages (function name and tty name).Note: printk(KERN_DEBUG) is retained here over pr_debug() since
messages can be enabled in non-DEBUG builds.Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman
19 May, 2015
1 commit
-
This resolves some tty driver merge issues.
Signed-off-by: Greg Kroah-Hartman
11 May, 2015
1 commit
-
A read() from a pty master may mistakenly indicate EOF (errno == -EIO)
after the pty slave has closed, even though input data remains to be read.
For example,pty slave | input worker | pty master
| |
| | n_tty_read()
pty_write() | | input avail? no
add data | | sleep
schedule worker --->| | .
|---> flush_to_ldisc() | .
pty_close() | fill read buffer | .
wait for worker | wakeup reader --->| .
| read buffer full? |---> input avail ? yes
|= 4096 so the ldisc read buffer
is empty
3. the subsequent read() occurs before the kicked worker has processed
more inputHowever, the underlying cause of the race is that data is pipelined, while
tty state is not; ie., data already written by the pty slave end is not
yet visible to the pty master end, but state changes by the pty slave end
are visible to the pty master end immediately.Pipeline the TTY_OTHER_CLOSED state through input worker to the reader.
1. Introduce TTY_OTHER_DONE which is set by the input worker when
TTY_OTHER_CLOSED is set and either the input buffers are flushed or
input processing has completed. Readers/polls are woken when
TTY_OTHER_DONE is set.
2. Reader/poll checks TTY_OTHER_DONE instead of TTY_OTHER_CLOSED.
3. A new input worker is started from pty_close() after setting
TTY_OTHER_CLOSED, which ensures the TTY_OTHER_DONE state will be
set if the last input worker is already finished (or just about to
exit).Remove tty_flush_to_ldisc(); no in-tree callers.
Fixes: 52bce7f8d4fc ("pty, n_tty: Simplify input processing on final close")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=96311
BugLink: http://bugs.launchpad.net/bugs/1429756
Cc: # 3.19+
Reported-by: Andy Whitcroft
Reported-by: H.J. Lu
Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman
07 May, 2015
2 commits
-
tty_name no longer uses the buf parameter, so remove it along with all
the 64 byte stack buffers that used to be passed in.Mostly generated by the coccinelle script
@depends on patch@
identifier buf;
constant C;
expression tty;
@@
- char buf[C];
allmodconfig compiles, so I'm fairly confident the stack buffers
weren't used for other purposes as well.Signed-off-by: Rasmus Villemoes
Reviewed-by: Peter Hurley
Acked-by: Jesper Nilsson
Acked-by: Dmitry Torokhov
Signed-off-by: Greg Kroah-Hartman -
All users of tty_name pass the result directly to a printf-like
function. This means we can actually let tty_name return the literal
"NULL tty" or tty->name directly, avoiding the strcpy and a lot of
medium-sized stack buffers. In preparation for that, make the return
type const char*.While at it, we can also constify the tty parameter.
Signed-off-by: Rasmus Villemoes
Reviewed-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman
28 Apr, 2015
1 commit
-
This is needed by Bluetooth hci_uart module to be able to change speed
of Bluetooth controller and local UART.Signed-off-by: Frederic Danis
Reviewed-by: Peter Hurley
Cc: Marcel Holtmann
Signed-off-by: Greg Kroah-Hartman
03 Feb, 2015
4 commits
-
tty_set_termios() is an internal helper intended for file scope use.
UART drivers which are capable of driving the RTS pin must
properly handle the tiocmset() method, regardless of termios settings.
A failure to do so is a UART driver bug and should be fixed there.
Do not use this interface to workaround UART driver bugs.Cc: Johan Hedberg
Cc:
Signed-off-by: Peter Hurley
Acked-by: Marcel Holtmann
Signed-off-by: Greg Kroah-Hartman -
BRKINT and ISIG requires input and output flush when a signal char
is received. However, the order of operations is significant since
parallel i/o may be ongoing.Merge the signal handling for BRKINT with ISIG handling.
Process the signal first. This ensures any ongoing i/o is aborted;
without this, a waiting writer may continue writing after the flush
occurs and after the signal char has been echoed.Write lock the termios_rwsem, which excludes parallel writers from
pushing new i/o until after the output buffers are flushed; claiming
the write lock is necessary anyway to exclude parallel readers while
the read buffer is flushed.Subclass the termios_rwsem for ptys since the slave pty performing
the flush may appear to reorder the termios_rwsem->tty buffer lock
lock order; adding annotation clarifies that
slave tty_buffer lock-> slave termios_rwsem -> master tty_buffer lock
is a valid lock order.Flush the echo buffer. In this context, the echo buffer is 'output'.
Otherwise, the output will appear discontinuous because the output buffer
was cleared which contains older output than the echo buffer.Open-code the read buffer flush since the input worker does not need
kicking (this is the input worker).Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
The pty driver does not clear its write buffer when commanded.
This is to avoid an apparent deadlock between parallel flushes from
both pty ends; specifically when handling either BRK or INTR input.
However, parallel flushes from this source is not possible since
the pty master can never be set to BRKINT or ISIG. Parallel flushes
from other sources are possible but these do not threaten deadlocks.Annotate the tty buffer mutex for lockdep to represent the nested
tty_buffer locking which occurs when the pty slave is processing input
(its buffer mutex held) and receives INTR or BRK and acquires the
linked tty buffer mutex via tty_buffer_flush().Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
Besides nested legacy_mutex locking which is required on pty pair
teardown, other nested pty operations require lock subclassing.Move lock subclass definition to tty interface header, include/linux/tty.h,
and document its use.Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman
07 Nov, 2014
1 commit
-
tty->closing is a bitfield member; prevent corruption from non-atomic
update by assigning a unique memory location.Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman
06 Nov, 2014
10 commits
-
serial_console_init() is not defined by the tty core; remove
declaration.Note that the powerpc arch boot code contains a serial_console_init()
declaration in arch/powerpc/boot/ops.h which is restricted to
the powerpc arch boot.Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
pcxe_open() has no definition in mainline; remove declaration.
Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
tty_ldisc_flush() first clears the line discipline input buffer,
then clears the tty flip buffers. However, this allows for existing
data in the tty flip buffers to be added after the ldisc input
buffer has been cleared, but before the flip buffers have been cleared.Add an optional ldisc parameter to tty_buffer_flush() to allow
tty_ldisc_flush() to pass the ldisc to clear.NB: Initially, the plan was to do this automatically in
tty_buffer_flush(). However, an audit of the behavior of existing
line disciplines showed that performing a ldisc buffer flush on
ioctl(TCFLSH) was not always the outcome. For example, some line
disciplines have flush_buffer() methods but not ioctl() methods,
so a ->flush_buffer() command would be unexpected.Reviewed-by: Alan Cox
Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
The tty_unhangup() function is not defined.
Reviewed-by: Alan Cox
Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
Eliminate the requirement of specifying the tty lock nesting at
lock time; instead, set the lock subclass for slave ptys at pty
install (normal ttys and master ptys use subclass 0).Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
When releasing the master pty, the slave pty also needs to be locked
to prevent concurrent tty count changes for the slave pty and to
ensure that only one parallel master and slave release observe the
final close, and proceed to destruct the pty pair. Conversely, when
releasing the slave pty, locking the master pty is not necessary
(since the master's state can be inferred by the slave tty count).Introduce tty_lock_slave()/tty_unlock_slave() which acquires/releases
the tty lock of the slave pty. Remove tty_lock_pair()/tty_unlock_pair().Dropping the tty_lock is no longer required to re-establish a stable
lock order.Reviewed-by: Alan Cox
Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
Passing the 'other' tty to tty_ldisc_release() only makes sense
for a pty pair; make o_tty function local instead.Reviewed-by: Alan Cox
Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
Now that re-open is not permitted for a legacy BSD pty master,
using TTY_CLOSING to indicate when a tty can be torn-down is
no longer necessary.Reviewed-by: Alan Cox
Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
Now that tty_ldisc_hangup() does not drop the tty lock, it is no
longer possible to observe TTY_HUPPING while holding the tty lock
on another cpu.Remove TTY_HUPPING bit definition.
Reviewed-by: Alan Cox
Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
tty_pair_get_pty() has no in-tree users and tty_pair_get_tty()
has only one file-local user. Remove the external declarations,
the export declarations, and declare tty_pair_get_tty() static.Signed-off-by: Peter Hurley
Reviewed-by: Alan Cox
Signed-off-by: Greg Kroah-Hartman
25 Sep, 2014
1 commit
-
Commit c545b66c6922b002b5fe224a6eaec58c913650b5,
'tty: Serialize tcflow() with other tty flow control changes' and
commit 99416322dd16b810ba74098cc50ef2a844091d35,
'tty: Workaround Alpha non-atomic byte storage in tty_struct' work around
compiler bugs and non-atomic storage on multiple arches by padding
bitfields out to the declared type which is unsigned long. However, the
width varies by arch.Pad bitfields to actual width of unsigned long (which is BITS_PER_LONG).
Reported-by: Fengguang Wu
Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman
24 Sep, 2014
5 commits
-
The Alpha EV4/EV5 cpus can corrupt adjacent byte and short data because
those cpus use RMW to store byte and short data. Thus, concurrent adjacent
byte stores could become corrupted, if serialized by a different lock.
tty_struct uses different locks to protect certain fields within the
structure, and thus is vulnerable to byte stores which are not atomic.Merge the ->ctrl_status byte and packet mode bit, both protected by the
->ctrl_lock, into an unsigned long.The padding bits are necessary to force the compiler to allocate the
type specified; otherwise, gcc will ignore the type specifier and
allocate the minimum number of bytes required to store the bitfield.
In turn, this would allow Alpha EV4/EV5 cpus to corrupt adjacent byte
or short storage (because those cpus use RMW to store byte and short data).gcc versions < 4.7.2 will also corrupt storage adjacent to bitfields
smaller than unsigned long on ia64, ppc64, hppa64, and sparc64, thus
requiring more than unsigned int storage (which would otherwise be
sufficient to fix the Alpha non-atomic storage problem).Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
Relocate the file-scope function, send_prio_char(), as a global
helper tty_send_xchar(). Remove the global declarations for
tty_write_lock()/tty_write_unlock(), as these are file-scope only now.Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
Use newly-introduced tty->flow_lock to serialize updates to
tty->flow_stopped (via tcflow()) and with concurrent tty flow
control changes from other sources.Merge the storage for ->stopped and ->flow_stopped, now that both
flags are serialized by ->flow_lock.The padding bits are necessary to force the compiler to allocate the
type specified; otherwise, gcc will ignore the type specifier and
allocate the minimum number of bytes necessary to store the bitfield.
In turn, this would allow Alpha EV4 and EV5 cpus to corrupt adjacent
byte storage because those cpus use RMW to store byte and short data.gcc versions < 4.7.2 will also corrupt storage adjacent to bitfields
smaller than unsigned long on ia64, ppc64, hppa64 and sparc64, thus
requiring more than unsigned int storage (which would otherwise be
sufficient to workaround the Alpha non-atomic byte/short storage problem).Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
Without serialization, the flow control state can become inverted
wrt. the actual hardware state. For example,CPU 0 | CPU 1
stop_tty() |
lock ctrl_lock |
tty->stopped = 1 |
unlock ctrl_lock |
| start_tty()
| lock ctrl_lock
| tty->stopped = 0
| unlock ctrl_lock
| driver->start()
driver->stop() |In this case, the flow control state now indicates the tty has
been started, but the actual hardware state has actually been stopped.Introduce tty->flow_lock spinlock to serialize tty flow control changes.
Split out unlocked __start_tty()/__stop_tty() flavors for use by
ioctl(TCXONC) in follow-on patch.Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman -
The stopped, hw_stopped, flow_stopped and packet bits are smp-unsafe
and interrupt-unsafe. For example,CPU 0 | CPU 1
|
tty->flow_stopped = 1 | tty->hw_stopped = 0One of these updates will be corrupted, as the bitwise operation
on the bitfield is non-atomic.Ensure each flag has a separate memory location, so concurrent
updates do not corrupt orthogonal states. Because DEC Alpha EV4 and EV5
cpus (from 1995) perform RMW on smaller-than-machine-word storage,
"separate memory location" must be int instead of byte.Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman
12 Jul, 2014
1 commit
-
The two functions alloc_tty_struct and initialize_tty_struct are
always called together. Merge them into alloc_tty_struct, updating its
prototype and the only two callers of these functions.Signed-off-by: Rasmus Villemoes
Signed-off-by: Greg Kroah-Hartman
04 May, 2014
1 commit
-
This reverts commit 6a20dbd6caa2358716136144bf524331d70b1e03.
Although the commit correctly identifies an unsafe race condition
between __tty_buffer_request_room() and flush_to_ldisc(), the commit
fixes the race with an unnecessary spinlock in a lockless algorithm.The follow-on commit, "tty: Fix lockless tty buffer race" fixes
the race locklessly.Signed-off-by: Peter Hurley
Signed-off-by: Greg Kroah-Hartman
25 Apr, 2014
1 commit
-
The race was introduced while development of linux-3.11 by
e8437d7ecbc50198705331449367d401ebb3181f and
e9975fdec0138f1b2a85b9624e41660abd9865d4.
Originally it was found and reproduced on linux-3.12.15 and
linux-3.12.15-rt25, by sending 500 byte blocks with 115kbaud to the
target uart in a loop with 100 milliseconds delay.In short:
1. The consumer flush_to_ldisc is on to remove the head tty_buffer.
2. The producer adds a number of bytes, so that a new tty_buffer must
be allocated and added by __tty_buffer_request_room.
3. The consumer removes the head tty_buffer element, without handling
newly committed data.Detailed example:
* Initial buffer:
* Head, Tail -> 0: used=250; commit=250; read=240; next=NULL
* Consumer: ''flush_to_ldisc''
* consumed 10 Byte
* buffer:
* Head, Tail -> 0: used=250; commit=250; read=250; next=NULL
{{{
count = head->commit - head->read; // count = 0
if (!count) { // enter
// INTERRUPTED BY PRODUCER ->
if (head->next == NULL)
break;
buf->head = head->next;
tty_buffer_free(port, head);
continue;
}
}}}
* Producer: tty_insert_flip_... 10 bytes + tty_flip_buffer_push
* buffer:
* Head, Tail -> 0: used=250; commit=250; read=250; next=NULL
* added 6 bytes: head-element filled to maximum.
* buffer:
* Head, Tail -> 0: used=256; commit=250; read=250; next=NULL
* added 4 bytes: __tty_buffer_request_room is called
* buffer:
* Head -> 0: used=256; commit=256; read=250; next=1
* Tail -> 1: used=4; commit=0; read=250 next=NULL
* push (tty_flip_buffer_push)
* buffer:
* Head -> 0: used=256; commit=256; read=250; next=1
* Tail -> 1: used=4; commit=4; read=250 next=NULL
* Consumer
{{{
count = head->commit - head->read;
if (!count) {
// INTERRUPTED BY PRODUCER next == NULL) // -> no break
break;
buf->head = head->next;
tty_buffer_free(port, head);
// ERROR: tty_buffer head freed -> 6 bytes lost
continue;
}
}}}This patch reintroduces a spin_lock to protect this case. Perhaps later
a lock-less solution could be found.Signed-off-by: Manfred Schlaegl
Cc: stable # 3.11
Signed-off-by: Greg Kroah-Hartman
03 Apr, 2014
1 commit
-
Pull networking updates from David Miller:
"Here is my initial pull request for the networking subsystem during
this merge window:1) Support for ESN in AH (RFC 4302) from Fan Du.
2) Add full kernel doc for ethtool command structures, from Ben
Hutchings.3) Add BCM7xxx PHY driver, from Florian Fainelli.
4) Export computed TCP rate information in netlink socket dumps, from
Eric Dumazet.5) Allow IPSEC SA to be dumped partially using a filter, from Nicolas
Dichtel.6) Convert many drivers to pci_enable_msix_range(), from Alexander
Gordeev.7) Record SKB timestamps more efficiently, from Eric Dumazet.
8) Switch to microsecond resolution for TCP round trip times, also
from Eric Dumazet.9) Clean up and fix 6lowpan fragmentation handling by making use of
the existing inet_frag api for it's implementation.10) Add TX grant mapping to xen-netback driver, from Zoltan Kiss.
11) Auto size SKB lengths when composing netlink messages based upon
past message sizes used, from Eric Dumazet.12) qdisc dumps can take a long time, add a cond_resched(), From Eric
Dumazet.13) Sanitize netpoll core and drivers wrt. SKB handling semantics.
Get rid of never-used-in-tree netpoll RX handling. From Eric W
Biederman.14) Support inter-address-family and namespace changing in VTI tunnel
driver(s). From Steffen Klassert.15) Add Altera TSE driver, from Vince Bridgers.
16) Optimizing csum_replace2() so that it doesn't adjust the checksum
by checksumming the entire header, from Eric Dumazet.17) Expand BPF internal implementation for faster interpreting, more
direct translations into JIT'd code, and much cleaner uses of BPF
filtering in non-socket ocntexts. From Daniel Borkmann and Alexei
Starovoitov"* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1976 commits)
netpoll: Use skb_irq_freeable to make zap_completion_queue safe.
net: Add a test to see if a skb is freeable in irq context
qlcnic: Fix build failure due to undefined reference to `vxlan_get_rx_port'
net: ptp: move PTP classifier in its own file
net: sxgbe: make "core_ops" static
net: sxgbe: fix logical vs bitwise operation
net: sxgbe: sxgbe_mdio_register() frees the bus
Call efx_set_channels() before efx->type->dimension_resources()
xen-netback: disable rogue vif in kthread context
net/mlx4: Set proper build dependancy with vxlan
be2net: fix build dependency on VxLAN
mac802154: make csma/cca parameters per-wpan
mac802154: allow only one WPAN to be up at any given time
net: filter: minor: fix kdoc in __sk_run_filter
netlink: don't compare the nul-termination in nla_strcmp
can: c_can: Avoid led toggling for every packet.
can: c_can: Simplify TX interrupt cleanup
can: c_can: Store dlc private
can: c_can: Reduce register access
can: c_can: Make the code readable
...
01 Mar, 2014
1 commit
-
The user-settable knob, low_latency, has been the source of
several BUG reports which stem from flush_to_ldisc() running
in interrupt context. Since 3.12, which added several sleeping
locks (termios_rwsem and buf->lock) to the input processing path,
the frequency of these BUG reports has increased.Note that changes in 3.12 did not introduce this regression;
sleeping locks were first added to the input processing path
with the removal of the BKL from N_TTY in commit
a88a69c91256418c5907c2f1f8a0ec0a36f9e6cc,
'n_tty: Fix loss of echoed characters and remove bkl from n_tty'
and later in commit 38db89799bdf11625a831c5af33938dcb11908b6,
'tty: throttling race fix'. Since those changes, executing
flush_to_ldisc() in interrupt_context (ie, low_latency set), is unsafe.However, since most devices do not validate if the low_latency
setting is appropriate for the context (process or interrupt) in
which they receive data, some reports are due to misconfiguration.
Further, serial dma devices for which dma fails, resort to
interrupt receiving as a backup without resetting low_latency.Historically, low_latency was used to force wake-up the reading
process rather than wait for the next scheduler tick. The
effect was to trim multiple milliseconds of latency from
when the process would receive new data.Recent tests [1] have shown that the reading process now receives
data with only 10's of microseconds latency without low_latency set.Remove the low_latency rx steering from tty_flip_buffer_push();
however, leave the knob as an optional hint to drivers that can
tune their rx fifos and such like. Cleanup stale code comments
regarding low_latency.[1] https://lkml.org/lkml/2014/2/20/434
"Yay.. thats an annoying historical pain in the butt gone."
-- Alan CoxReported-by: Beat Bolli
Reported-by: Pavel Roskin
Acked-by: David Sterba
Cc: Grant Edwards
Cc: Stanislaw Gruszka
Cc: Hal Murray
Cc: # 3.12.x+
Signed-off-by: Peter Hurley
Signed-off-by: Alan Cox
Signed-off-by: Greg Kroah-Hartman
15 Feb, 2014
1 commit
-
The tty core supports two models for handling tty_port lifetimes;
the tty_port can use the kref supplied by tty_port (which will
automatically destruct the tty_port when the ref count drops to
zero) or it can destruct the tty_port manually.For tty drivers that choose to use the port kref to manage the
tty_port lifetime, it is not possible to safely acquire a port
reference conditionally. If the last reference is released after
evaluating the condition but before acquiring the reference, a
bogus reference will be held while the tty_port destruction
commences.Rather, only acquire a port reference if the ref count is non-zero
and allow the caller to distinguish if a reference has successfully
been acquired.Cc: Jiri Slaby
Signed-off-by: Peter Hurley
Acked-by: Greg Kroah-Hartman
Tested-By: Alexander Holler
Signed-off-by: Marcel Holtmann
21 Jan, 2014
1 commit
-
Pull USB updates from Greg KH:
"Here's the big USB pull request for 3.14-rc1Lots of little things all over the place, and the usual USB gadget
updates, and XHCI fixes (some for an issue reported by a lot of
people). USB PHY updates as well as chipidea updates and fixes.All of these have been in the linux-next tree with no reported issues"
* tag 'usb-3.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (318 commits)
usb: chipidea: udc: using MultO at TD as real mult value for ISO-TX
usb: chipidea: need to mask INT_STATUS when write otgsc
usb: chipidea: put hw_phymode_configure before ci_usb_phy_init
usb: chipidea: Fix Internal error: : 808 [#1] ARM related to STS flag
usb: chipidea: imx: set CI_HDRC_IMX28_WRITE_FIX for imx28
usb: chipidea: add freescale imx28 special write register method
usb: ehci: add freescale imx28 special write register method
usb: core: check for valid id_table when using the RefId feature
usb: cdc-wdm: resp_count can be 0 even if WDM_READ is set
usb: core: bail out if user gives an unknown RefId when using new_id
usb: core: allow a reference device for new_id
usb: core: add sanity checks when using bInterfaceClass with new_id
USB: image: correct spelling mistake in comment
USB: c67x00: correct spelling mistakes in comments
usb: delete non-required instances of include
usb:hub set hub->change_bits when over-current happens
Revert "usb: chipidea: imx: set CI_HDRC_IMX28_WRITE_FIX for imx28"
xhci: Set scatter-gather limit to avoid failed block writes.
xhci: Avoid infinite loop when sg urb requires too many trbs
usb: gadget: remove unused variable in gr_queue_int()
...