linux-toradex.git/drivers/tty, branch v3.14.3 Linux kernel for Apalis and Colibri modules hvc: ensure hvc_init is only ever called once in hvc_console.c 2014-05-06T14:59:33+00:00 Paul Gortmaker paul.gortmaker@windriver.com 2014-01-14T21:03:37+00:00 df55b19e5b501e69790ccb5cc5deb45b7245cc78 commit f76a1cbed18c86e2d192455f0daebb48458965f3 upstream. Commit 3e6c6f630a5282df8f3393a59f10eb9c56536d23 ("Delay creation of khcvd thread") moved the call of hvc_init from being a device_initcall into hvc_alloc, and used a non-null hvc_driver as indication of whether hvc_init had already been called. The problem with this is that hvc_driver is only assigned a value at the bottom of hvc_init, and so there is a window where multiple hvc_alloc calls can be in progress at the same time and hence try and call hvc_init multiple times. Previously the use of device_init guaranteed that hvc_init was only called once. This manifests itself as sporadic instances of two hvc_init calls racing each other, and with the loser of the race getting -EBUSY from tty_register_driver() and hence that virtual console fails: Couldn't register hvc console driver virtio-ports vport0p1: error -16 allocating hvc for port Here we add an atomic_t to guarantee we'll never run hvc_init twice. Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Fixes: 3e6c6f630a52 ("Delay creation of khcvd thread") Reported-by: Jim Somerville <Jim.Somerville@windriver.com> Tested-by: Jim Somerville <Jim.Somerville@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit f76a1cbed18c86e2d192455f0daebb48458965f3 upstream.

Commit 3e6c6f630a5282df8f3393a59f10eb9c56536d23 ("Delay creation of
khcvd thread") moved the call of hvc_init from being a device_initcall
into hvc_alloc, and used a non-null hvc_driver as indication of whether
hvc_init had already been called.

The problem with this is that hvc_driver is only assigned a value
at the bottom of hvc_init, and so there is a window where multiple
hvc_alloc calls can be in progress at the same time and hence try
and call hvc_init multiple times.  Previously the use of device_init
guaranteed that hvc_init was only called once.

This manifests itself as sporadic instances of two hvc_init calls
racing each other, and with the loser of the race getting -EBUSY
from tty_register_driver() and hence that virtual console fails:

    Couldn't register hvc console driver
    virtio-ports vport0p1: error -16 allocating hvc for port

Here we add an atomic_t to guarantee we'll never run hvc_init twice.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: 3e6c6f630a52 ("Delay creation of khcvd thread")
Reported-by: Jim Somerville <Jim.Somerville@windriver.com>
Tested-by: Jim Somerville <Jim.Somerville@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty: Fix low_latency BUG 2014-04-27T00:19:04+00:00 Peter Hurley peter@hurleysoftware.com 2014-02-22T12:31:21+00:00 4f1f4df2c1aee858da70f91970f6c9cb651a63de commit a9c3f68f3cd8d55f809fbdb0c138ed061ea1bd25 upstream. 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 Cox Reported-by: Beat Bolli <bbolli@ewanet.ch> Reported-by: Pavel Roskin <proski@gnu.org> Acked-by: David Sterba <dsterba@suse.cz> Cc: Grant Edwards <grant.b.edwards@gmail.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Hal Murray <murray+fedora@ip-64-139-1-69.sjc.megapath.net> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit a9c3f68f3cd8d55f809fbdb0c138ed061ea1bd25 upstream.

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 Cox

Reported-by: Beat Bolli <bbolli@ewanet.ch>
Reported-by: Pavel Roskin <proski@gnu.org>
Acked-by: David Sterba <dsterba@suse.cz>
Cc: Grant Edwards <grant.b.edwards@gmail.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Hal Murray <murray+fedora@ip-64-139-1-69.sjc.megapath.net>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty: Set correct tty name in 'active' sysfs attribute 2014-04-27T00:19:04+00:00 Hannes Reinecke hare@suse.de 2014-02-27T11:30:51+00:00 192ae8160c9465dd3f0c6650b29cc4ad019bc4e2 commit 723abd87f6e536f1353c8f64f621520bc29523a3 upstream. The 'active' sysfs attribute should refer to the currently active tty devices the console is running on, not the currently active console. The console structure doesn't refer to any device in sysfs, only the tty the console is running on has. So we need to print out the tty names in 'active', not the console names. There is one special-case, which is tty0. If the console is directed to it, we want 'tty0' to show up in the file, so user-space knows that the messages get forwarded to the active VT. The ->device() callback would resolve tty0, though. Hence, treat it special and don't call into the VT layer to resolve it (plymouth is known to depend on it). Cc: Lennart Poettering <lennart@poettering.net> Cc: Kay Sievers <kay@vrfy.org> Cc: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Werner Fink <werner@suse.de> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 723abd87f6e536f1353c8f64f621520bc29523a3 upstream.

The 'active' sysfs attribute should refer to the currently active tty
devices the console is running on, not the currently active console. The
console structure doesn't refer to any device in sysfs, only the tty the
console is running on has. So we need to print out the tty names in
'active', not the console names.

There is one special-case, which is tty0. If the console is directed to
it, we want 'tty0' to show up in the file, so user-space knows that the
messages get forwarded to the active VT. The ->device() callback would
resolve tty0, though. Hence, treat it special and don't call into the VT
layer to resolve it (plymouth is known to depend on it).

Cc: Lennart Poettering <lennart@poettering.net>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Werner Fink <werner@suse.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sparc: serial: Clean up the locking for -rt 2014-03-06T21:32:25+00:00 David Miller davem@davemloft.net 2014-03-04T20:28:35+00:00 e58e241c1788856f69d58821e91e5c988905252d Signed-off-by: David S. Miller <davem@davemloft.net> Tested-by: Allen Pais <allen.pais@oracle.com> 
Signed-off-by: David S. Miller <davem@davemloft.net>
Tested-by: Allen Pais <allen.pais@oracle.com>
Revert "tty: Set correct tty name in 'active' sysfs attribute" 2014-02-22T22:31:04+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2014-02-22T22:31:04+00:00 5c0a2450d695bbe32b1fb81c07751bcbea64f084 This reverts commit d8a5dc3033af2fd6d16030d2ee4fbd073460fe54. This breaks plymouth installs, either because plymouth is using the file "incorrectly" or because the patch is incorrect. Either way, this needs to be reverted until it is all figured out. Reported-by: Josh Boyer <jwboyer@fedoraproject.org> Reported-by: Ray Strode <halfline@gmail.com> Cc: Lennart Poettering <lennart@poettering.net> Cc: Kay Sievers <kay@vrfy.org> Cc: Jiri Slaby <jslaby@suse.cz> Cc: David Herrmann <dh.herrmann@gmail.com> Cc: Werner Fink <werner@suse.de> Cc: Hannes Reinecke <hare@suse.de> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
This reverts commit d8a5dc3033af2fd6d16030d2ee4fbd073460fe54.

This breaks plymouth installs, either because plymouth is using the file
"incorrectly" or because the patch is incorrect.  Either way, this needs
to be reverted until it is all figured out.

Reported-by: Josh Boyer <jwboyer@fedoraproject.org>
Reported-by: Ray Strode <halfline@gmail.com>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Werner Fink <werner@suse.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
vt: Fix secure clear screen 2014-02-13T19:12:00+00:00 Petr Písař petr.pisar@atlas.cz 2014-02-06T20:01:23+00:00 0930b0950a8996aa88b0d2ba4bb2bab27cc36bc7 \E[3J console code (secure clear screen) needs to update_screen(vc) in order to write-through blanks into off-screen video memory. This has been removed accidentally in 3.6 by: commit 81732c3b2fede049a692e58a7ceabb6d18ffb18c Author: Jean-François Moine <moinejf@free.fr> Date: Thu Sep 6 19:24:13 2012 +0200 tty vt: Fix line garbage in virtual console on command line edition Signed-off-by: Petr Písař <petr.pisar@atlas.cz> Cc: stable <stable@vger.kernel.org> # 3.6 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
\E[3J console code (secure clear screen) needs to update_screen(vc)
in order to write-through blanks into off-screen video memory.

This has been removed accidentally in 3.6 by:

commit 81732c3b2fede049a692e58a7ceabb6d18ffb18c
Author: Jean-François Moine <moinejf@free.fr>
Date:   Thu Sep 6 19:24:13 2012 +0200

    tty vt: Fix line garbage in virtual console on command line edition

Signed-off-by: Petr Písař <petr.pisar@atlas.cz>
Cc: stable <stable@vger.kernel.org> # 3.6
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: 8250: Support XR17V35x fraction divisor 2014-02-13T18:02:19+00:00 Joe Schultz jschultz@xes-inc.com 2014-02-12T00:30:01+00:00 45a7bd635930baa960b6817674c64bdfb8f39570 The Exar XR17V35x family of UARTs have an additional fractional divisor register (DLD) which was not being used. Calculate and set this register for these devices to reduce their baud rate error. Signed-off-by: Joe Schultz <jschultz@xes-inc.com> Signed-off-by: Aaron Sierra <asierra@xes-inc.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
The Exar XR17V35x family of UARTs have an additional fractional divisor
register (DLD) which was not being used. Calculate and set this
register for these devices to reduce their baud rate error.

Signed-off-by: Joe Schultz <jschultz@xes-inc.com>
Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
n_tty: Fix stale echo output 2014-02-13T18:02:19+00:00 Peter Hurley peter@hurleysoftware.com 2014-02-11T21:34:55+00:00 e2613be5093d04e6589924d36a1e363eef3c87c7 When echoes cannot be flushed to output (usually because the tty has no more write room) and L_ECHO is subsequently turned off, then when L_ECHO is turned back on, stale echoes are output. Output completed echoes regardless of the L_ECHO setting: 1. before normal writes to that tty 2. if the tty was stopped by soft flow control and is being restarted Reported-by: Mikulas Patocka <mpatocka@redhat.com> Cc: <stable@vger.kernel.org> # 3.13.x Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
When echoes cannot be flushed to output (usually because the tty
has no more write room) and L_ECHO is subsequently turned off, then
when L_ECHO is turned back on, stale echoes are output.

Output completed echoes regardless of the L_ECHO setting:
  1. before normal writes to that tty
  2. if the tty was stopped by soft flow control and is being
     restarted

Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: <stable@vger.kernel.org> # 3.13.x
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: sirf: fix kernel panic caused by unpaired spinlock 2014-02-13T18:02:19+00:00 Qipan Li Qipan.Li@csr.com 2014-01-27T06:23:39+00:00 fb78b811422cd2d8c8605949cc4cc13618347ad5 commit 8b9ade9f74f8a279 coming from Viresh Kumar "tty: serial: sirfsoc: drop uart_port->lock before calling tty_flip_buffer_push()" broke sirfsoc uart driver by knic: [ 5.129122] BUG: spinlock already unlocked on CPU#0, ip6tables/1331 [ 5.132554] lock: sirfsoc_uart_ports+0x4/0x8a0, .magic: dead4ead, .owner: <none>/-1, .owner_cpu: -1 [ 5.141651] CPU: 0 PID: 1331 Comm: ip6tables Tainted: G W O 3.10.16 #3 [ 5.148866] [<c0013528>] (unwind_backtrace+0x0/0xe0) from [<c0010e70>] (show_stack+0x10/0x14) [ 5.157362] [<c0010e70>] (show_stack+0x10/0x14) from [<c01a5e68>] (do_raw_spin_unlock+0x40/0xc8) [ 5.166125] [<c01a5e68>] (do_raw_spin_unlock+0x40/0xc8) from [<c03ff8b4>] (_raw_spin_unlock+0x8/0x40) [ 5.175322] [<c03ff8b4>] (_raw_spin_unlock+0x8/0x40) from [<c0203fcc>] (sirfsoc_uart_pio_rx_chars+0xa4/0xc0) [ 5.185120] [<c0203fcc>] (sirfsoc_uart_pio_rx_chars+0xa4/0xc0) from [<c0204fb8>] (sirfsoc_rx_tmo_process_tl+0xdc/0x1e0) [ 5.195875] [<c0204fb8>] (sirfsoc_rx_tmo_process_tl+0xdc/0x1e0) from [<c0024b50>] (tasklet_action+0x8c/0xec) [ 5.205673] [<c0024b50>] (tasklet_action+0x8c/0xec) from [<c00242a8>] (__do_softirq+0xec/0x1d4) [ 5.214347] [<c00242a8>] (__do_softirq+0xec/0x1d4) from [<c0024428>] (do_softirq+0x48/0x54) [ 5.222674] [<c0024428>] (do_softirq+0x48/0x54) from [<c0024690>] (irq_exit+0x74/0xc0) [ 5.230573] [<c0024690>] (irq_exit+0x74/0xc0) from [<c000e1e8>] (handle_IRQ+0x6c/0x90) [ 5.238465] [<c000e1e8>] (handle_IRQ+0x6c/0x90) from [<c000d500>] (__irq_svc+0x40/0x70) [ 5.246446] [<c000d500>] (__irq_svc+0x40/0x70) from [<c0092e7c>] (mark_page_accessed+0xc/0x68) [ 5.255034] [<c0092e7c>] (mark_page_accessed+0xc/0x68) from [<c00a2a4c>] (unmap_single_vma+0x3bc/0x550) [ 5.264402] [<c00a2a4c>] (unmap_single_vma+0x3bc/0x550) from [<c00a3b4c>] (unmap_vmas+0x44/0x54) [ 5.273164] [<c00a3b4c>] (unmap_vmas+0x44/0x54) from [<c00a81a8>] (exit_mmap+0xc4/0x1e0) [ 5.281233] [<c00a81a8>] (exit_mmap+0xc4/0x1e0) from [<c001bb78>] (mmput+0x3c/0xdc) [ 5.288868] [<c001bb78>] (mmput+0x3c/0xdc) from [<c0021b0c>] (do_exit+0x30c/0x828) [ 5.296413] [<c0021b0c>] (do_exit+0x30c/0x828) from [<c0022dac>] (do_group_exit+0x4c/0xb0) [ 5.304653] [<c0022dac>] (do_group_exit+0x4c/0xb0) from [<c0022e20>] (__wake_up_parent+0x0/0x18) Root cause: the commit dropped uart_port->lock before calling tty_flip_buffer_push(), but in sirfsoc-uart, sirfsoc_uart_pio_rx_chars() can be called by sirfsoc_rx_tmo_process_tl(). here uart_port->lock has not been taken yet. so that caused unpaired lock/unlock. Solution: This patch is doing a quick fix for that, it adds spin_lock/unlock(&port->lock) protect to sirfsoc_uart_pio_rx_chars() in sirfsoc_rx_tmo_process_tl() to keep spin_lock/unlock in pair. Signed-off-by: Qipan Li <Qipan.Li@csr.com> Signed-off-by: Barry Song <Baohua.Song@csr.com> Cc: stable <stable@vger.kernel.org> # 3.12 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 8b9ade9f74f8a279 coming from Viresh Kumar "tty: serial: sirfsoc: drop
uart_port->lock before calling tty_flip_buffer_push()" broke sirfsoc uart
driver by knic:

	[    5.129122] BUG: spinlock already unlocked on CPU#0, ip6tables/1331
	[    5.132554]  lock: sirfsoc_uart_ports+0x4/0x8a0, .magic: dead4ead,
	.owner: <none>/-1, .owner_cpu: -1
	[    5.141651] CPU: 0 PID: 1331 Comm: ip6tables Tainted: G
	W  O 3.10.16 #3
	[    5.148866] [<c0013528>] (unwind_backtrace+0x0/0xe0) from
	[<c0010e70>] (show_stack+0x10/0x14)
	[    5.157362] [<c0010e70>] (show_stack+0x10/0x14) from
	[<c01a5e68>] (do_raw_spin_unlock+0x40/0xc8)
	[    5.166125] [<c01a5e68>] (do_raw_spin_unlock+0x40/0xc8) from
	[<c03ff8b4>] (_raw_spin_unlock+0x8/0x40)
	[    5.175322] [<c03ff8b4>] (_raw_spin_unlock+0x8/0x40) from
	[<c0203fcc>] (sirfsoc_uart_pio_rx_chars+0xa4/0xc0)
	[    5.185120] [<c0203fcc>]
	(sirfsoc_uart_pio_rx_chars+0xa4/0xc0) from [<c0204fb8>]
	(sirfsoc_rx_tmo_process_tl+0xdc/0x1e0)
	[    5.195875] [<c0204fb8>]
	(sirfsoc_rx_tmo_process_tl+0xdc/0x1e0) from [<c0024b50>]
	(tasklet_action+0x8c/0xec)
	[    5.205673] [<c0024b50>] (tasklet_action+0x8c/0xec) from
	[<c00242a8>] (__do_softirq+0xec/0x1d4)
	[    5.214347] [<c00242a8>] (__do_softirq+0xec/0x1d4) from
	[<c0024428>] (do_softirq+0x48/0x54)
	[    5.222674] [<c0024428>] (do_softirq+0x48/0x54) from
	[<c0024690>] (irq_exit+0x74/0xc0)
	[    5.230573] [<c0024690>] (irq_exit+0x74/0xc0) from
	[<c000e1e8>] (handle_IRQ+0x6c/0x90)
	[    5.238465] [<c000e1e8>] (handle_IRQ+0x6c/0x90) from
	[<c000d500>] (__irq_svc+0x40/0x70)
	[    5.246446] [<c000d500>] (__irq_svc+0x40/0x70) from
	[<c0092e7c>] (mark_page_accessed+0xc/0x68)
	[    5.255034] [<c0092e7c>] (mark_page_accessed+0xc/0x68) from
	[<c00a2a4c>] (unmap_single_vma+0x3bc/0x550)
	[    5.264402] [<c00a2a4c>] (unmap_single_vma+0x3bc/0x550) from
	[<c00a3b4c>] (unmap_vmas+0x44/0x54)
	[    5.273164] [<c00a3b4c>] (unmap_vmas+0x44/0x54) from
	[<c00a81a8>] (exit_mmap+0xc4/0x1e0)
	[    5.281233] [<c00a81a8>] (exit_mmap+0xc4/0x1e0) from
	[<c001bb78>] (mmput+0x3c/0xdc)
	[    5.288868] [<c001bb78>] (mmput+0x3c/0xdc) from [<c0021b0c>]
	(do_exit+0x30c/0x828)
	[    5.296413] [<c0021b0c>] (do_exit+0x30c/0x828) from
	[<c0022dac>] (do_group_exit+0x4c/0xb0)
	[    5.304653] [<c0022dac>] (do_group_exit+0x4c/0xb0) from
	[<c0022e20>] (__wake_up_parent+0x0/0x18)

Root cause:
the commit dropped uart_port->lock before calling tty_flip_buffer_push(), but in sirfsoc-uart,
sirfsoc_uart_pio_rx_chars() can be called by sirfsoc_rx_tmo_process_tl(). here uart_port->lock
has not been taken yet. so that caused unpaired lock/unlock.

Solution:
This patch is doing a quick fix for that, it adds spin_lock/unlock(&port->lock) protect to
sirfsoc_uart_pio_rx_chars() in sirfsoc_rx_tmo_process_tl() to keep spin_lock/unlock in pair.

Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Cc: stable <stable@vger.kernel.org> # 3.12
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: 8250_pci: unbreak last serial ports on NetMos 9865 cards 2014-02-13T17:57:33+00:00 Dmitry Eremin-Solenikov dbaryshkov@gmail.com 2014-02-11T10:18:13+00:00 333c085e4b0cd9df04b087d29f87969a4e26dfa9 Aparently 9865 uses standard BAR encoding scheme (unlike 99xx cards). Current pci_netmos_9900_setup() uses wrong BAR indices for the 9865 PCI device, function 2. Using standard BAR indices makes all 6 ports work for me. Thus disable the NetMos 9900 quirk for NetMos 9865 pci device. For the reference, here is the relevant part of lspci for my device: 02:07.0 Serial controller: MosChip Semiconductor Technology Ltd. PCI 9865 Multi-I/O Controller (prog-if 02 [16550]) Subsystem: Device a000:1000 Flags: bus master, medium devsel, latency 32, IRQ 17 I/O ports at ac00 [size=8] Memory at fcfff000 (32-bit, non-prefetchable) [size=4K] Memory at fcffe000 (32-bit, non-prefetchable) [size=4K] Capabilities: [48] Power Management version 2 Kernel driver in use: serial 02:07.1 Serial controller: MosChip Semiconductor Technology Ltd. PCI 9865 Multi-I/O Controller (prog-if 02 [16550]) Subsystem: Device a000:1000 Flags: bus master, medium devsel, latency 32, IRQ 18 I/O ports at a800 [size=8] Memory at fcffd000 (32-bit, non-prefetchable) [size=4K] Memory at fcffc000 (32-bit, non-prefetchable) [size=4K] Capabilities: [48] Power Management version 2 Kernel driver in use: serial 02:07.2 Communication controller: MosChip Semiconductor Technology Ltd. PCI 9865 Multi-I/O Controller Subsystem: Device a000:3004 Flags: bus master, medium devsel, latency 32, IRQ 19 I/O ports at a400 [size=8] I/O ports at a000 [size=8] I/O ports at 9c00 [size=8] I/O ports at 9800 [size=8] Memory at fcffb000 (32-bit, non-prefetchable) [size=4K] Capabilities: [48] Power Management version 2 Kernel driver in use: serial Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Aparently 9865 uses standard BAR encoding scheme (unlike 99xx cards).
Current pci_netmos_9900_setup() uses wrong BAR indices for the 9865 PCI
device, function 2. Using standard BAR indices makes all 6 ports work
for me. Thus disable the NetMos 9900 quirk for NetMos 9865 pci device.

For the reference, here is the relevant part of lspci for my device:

02:07.0 Serial controller: MosChip Semiconductor Technology Ltd. PCI
9865 Multi-I/O Controller (prog-if 02 [16550])
	Subsystem: Device a000:1000
	Flags: bus master, medium devsel, latency 32, IRQ 17
	I/O ports at ac00 [size=8]
	Memory at fcfff000 (32-bit, non-prefetchable) [size=4K]
	Memory at fcffe000 (32-bit, non-prefetchable) [size=4K]
	Capabilities: [48] Power Management version 2
	Kernel driver in use: serial

02:07.1 Serial controller: MosChip Semiconductor Technology Ltd. PCI
9865 Multi-I/O Controller (prog-if 02 [16550])
	Subsystem: Device a000:1000
	Flags: bus master, medium devsel, latency 32, IRQ 18
	I/O ports at a800 [size=8]
	Memory at fcffd000 (32-bit, non-prefetchable) [size=4K]
	Memory at fcffc000 (32-bit, non-prefetchable) [size=4K]
	Capabilities: [48] Power Management version 2
	Kernel driver in use: serial

02:07.2 Communication controller: MosChip Semiconductor Technology Ltd.
PCI 9865 Multi-I/O Controller
	Subsystem: Device a000:3004
	Flags: bus master, medium devsel, latency 32, IRQ 19
	I/O ports at a400 [size=8]
	I/O ports at a000 [size=8]
	I/O ports at 9c00 [size=8]
	I/O ports at 9800 [size=8]
	Memory at fcffb000 (32-bit, non-prefetchable) [size=4K]
	Capabilities: [48] Power Management version 2
	Kernel driver in use: serial

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>