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commit dce05aa6eec977f1472abed95ccd71276b9a3864 upstream.
Avoid global variables (namely sel_cons) by introducing vc_is_sel. It
checks whether the parameter is the current selection console. This will
help putting sel_cons to a struct later.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e8c75a30a23c6ba63f4ef6895cbf41fd42f21aa2 upstream.
sel_lock cannot nest in the console lock. Thanks to syzkaller, the
kernel states firmly:
> WARNING: possible circular locking dependency detected
> 5.6.0-rc3-syzkaller #0 Not tainted
> ------------------------------------------------------
> syz-executor.4/20336 is trying to acquire lock:
> ffff8880a2e952a0 (&tty->termios_rwsem){++++}, at: tty_unthrottle+0x22/0x100 drivers/tty/tty_ioctl.c:136
>
> but task is already holding lock:
> ffffffff89462e70 (sel_lock){+.+.}, at: paste_selection+0x118/0x470 drivers/tty/vt/selection.c:374
>
> which lock already depends on the new lock.
>
> the existing dependency chain (in reverse order) is:
>
> -> #2 (sel_lock){+.+.}:
> mutex_lock_nested+0x1b/0x30 kernel/locking/mutex.c:1118
> set_selection_kernel+0x3b8/0x18a0 drivers/tty/vt/selection.c:217
> set_selection_user+0x63/0x80 drivers/tty/vt/selection.c:181
> tioclinux+0x103/0x530 drivers/tty/vt/vt.c:3050
> vt_ioctl+0x3f1/0x3a30 drivers/tty/vt/vt_ioctl.c:364
This is ioctl(TIOCL_SETSEL).
Locks held on the path: console_lock -> sel_lock
> -> #1 (console_lock){+.+.}:
> console_lock+0x46/0x70 kernel/printk/printk.c:2289
> con_flush_chars+0x50/0x650 drivers/tty/vt/vt.c:3223
> n_tty_write+0xeae/0x1200 drivers/tty/n_tty.c:2350
> do_tty_write drivers/tty/tty_io.c:962 [inline]
> tty_write+0x5a1/0x950 drivers/tty/tty_io.c:1046
This is write().
Locks held on the path: termios_rwsem -> console_lock
> -> #0 (&tty->termios_rwsem){++++}:
> down_write+0x57/0x140 kernel/locking/rwsem.c:1534
> tty_unthrottle+0x22/0x100 drivers/tty/tty_ioctl.c:136
> mkiss_receive_buf+0x12aa/0x1340 drivers/net/hamradio/mkiss.c:902
> tty_ldisc_receive_buf+0x12f/0x170 drivers/tty/tty_buffer.c:465
> paste_selection+0x346/0x470 drivers/tty/vt/selection.c:389
> tioclinux+0x121/0x530 drivers/tty/vt/vt.c:3055
> vt_ioctl+0x3f1/0x3a30 drivers/tty/vt/vt_ioctl.c:364
This is ioctl(TIOCL_PASTESEL).
Locks held on the path: sel_lock -> termios_rwsem
> other info that might help us debug this:
>
> Chain exists of:
> &tty->termios_rwsem --> console_lock --> sel_lock
Clearly. From the above, we have:
console_lock -> sel_lock
sel_lock -> termios_rwsem
termios_rwsem -> console_lock
Fix this by reversing the console_lock -> sel_lock dependency in
ioctl(TIOCL_SETSEL). First, lock sel_lock, then console_lock.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: syzbot+26183d9746e62da329b8@syzkaller.appspotmail.com
Fixes: 07e6124a1a46 ("vt: selection, close sel_buffer race")
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200228115406.5735-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 4b70dd57a15d2f4685ac6e38056bad93e81e982f upstream.
We need to nest the console lock in sel_lock, so we have to push it down
a bit. Fortunately, the callers of set_selection_* just lock the console
lock around the function call. So moving it down is easy.
In the next patch, we switch the order.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Fixes: 07e6124a1a46 ("vt: selection, close sel_buffer race")
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200228115406.5735-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 07e6124a1a46b4b5a9b3cacc0c306b50da87abf5 upstream.
syzkaller reported this UAF:
BUG: KASAN: use-after-free in n_tty_receive_buf_common+0x2481/0x2940 drivers/tty/n_tty.c:1741
Read of size 1 at addr ffff8880089e40e9 by task syz-executor.1/13184
CPU: 0 PID: 13184 Comm: syz-executor.1 Not tainted 5.4.7 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
...
kasan_report+0xe/0x20 mm/kasan/common.c:634
n_tty_receive_buf_common+0x2481/0x2940 drivers/tty/n_tty.c:1741
tty_ldisc_receive_buf+0xac/0x190 drivers/tty/tty_buffer.c:461
paste_selection+0x297/0x400 drivers/tty/vt/selection.c:372
tioclinux+0x20d/0x4e0 drivers/tty/vt/vt.c:3044
vt_ioctl+0x1bcf/0x28d0 drivers/tty/vt/vt_ioctl.c:364
tty_ioctl+0x525/0x15a0 drivers/tty/tty_io.c:2657
vfs_ioctl fs/ioctl.c:47 [inline]
It is due to a race between parallel paste_selection (TIOCL_PASTESEL)
and set_selection_user (TIOCL_SETSEL) invocations. One uses sel_buffer,
while the other frees it and reallocates a new one for another
selection. Add a mutex to close this race.
The mutex takes care properly of sel_buffer and sel_buffer_lth only. The
other selection global variables (like sel_start, sel_end, and sel_cons)
are protected only in set_selection_user. The other functions need quite
some more work to close the races of the variables there. This is going
to happen later.
This likely fixes (I am unsure as there is no reproducer provided) bug
206361 too. It was marked as CVE-2020-8648.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: syzbot+59997e8d5cbdc486e6f6@syzkaller.appspotmail.com
References: https://bugzilla.kernel.org/show_bug.cgi?id=206361
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200210081131.23572-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 687bff0cd08f790d540cfb7b2349f0d876cdddec upstream.
When pasting a selection to a vt, the task is set as INTERRUPTIBLE while
waiting for a tty to unthrottle. But signals are not handled at all.
Normally, this is not a problem as tty_ldisc_receive_buf receives all
the goods and a user has no reason to interrupt the task.
There are two scenarios where this matters:
1) when the tty is throttled and a signal is sent to the process, it
spins on a CPU until the tty is unthrottled. schedule() does not
really echedule, but returns immediately, of course.
2) when the sel_buffer becomes invalid, KASAN prevents any reads from it
and the loop simply does not proceed and spins forever (causing the
tty to throttle, but the code never sleeps, the same as above). This
sometimes happens as there is a race in the sel_buffer handling code.
So add signal handling to this ioctl (TIOCL_PASTESEL) and return -EINTR
in case a signal is pending.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200210081131.23572-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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For some reason a handful of ISO-8859-1 symbols are excluded from "word
chars" while the vast majority of Unicode is hard-coded as included, even
when inappropriate (we really would want to _not_ select line-drawing/etc).
Those symbols are: ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿×÷
Thus, let's not special-case any non-ASCII anymore. Attempts to set these
via ioctl will be silently ignored.
As an extra bonus, we debloat the kernel by 128 bytes.
Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Since forever, gpm was this code's only user, and it overrides the table on
start so the default was never seen -- until Bill Allombert's "consolation"
came in. The in-kernel set is "A-Za-z0-9_" which fails to catch typical
file names, etc. Let's change this to gpm's conservative default, ie
"-A-Za-z0-9_./"; most terminals include more, for example xfce4-terminal has
"-A-Za-z0-9,./?%&#:_=+@~".
There's some discussion at https://bugs.debian.org/846587
Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This was entirely automated, using the script by Al:
PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)
to do the replacement at the end of the merge window.
Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Abstract TTY_THROTTLED bit tests with tty_throttled().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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tty file_operations (read/write/ioctl) wait for the ldisc reference
indefinitely (until ldisc lifetime events, such as hangup or TIOCSETD,
finish). Since hangup now destroys the ldisc and does not instance
another copy, file_operations must now be prepared to receive a NULL
ldisc reference from tty_ldisc_ref_wait():
CPU 0 CPU 1
----- -----
(*f_op->read)() => tty_read()
__tty_hangup()
...
f_op = &hung_up_tty_fops;
...
tty_ldisc_hangup()
tty_ldisc_lock()
tty_ldisc_kill()
tty->ldisc = NULL
tty_ldisc_unlock()
ld = tty_ldisc_ref_wait()
/* ld == NULL */
Instead, the action taken now is to return the same value as if the
tty had been hungup a moment earlier:
CPU 0 CPU 1
----- -----
__tty_hangup()
...
f_op = &hung_up_tty_fops;
(*f_op->read)() => hung_up_tty_read()
return 0;
...
tty_ldisc_hangup()
tty_ldisc_lock()
tty_ldisc_kill()
tty->ldisc = NULL
tty_ldisc_unlock()
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Pasting text with gpm on a VC produced warning [1]. Reset task state
to TASK_RUNNING in the paste_selection() loop, if the loop did not
sleep.
[1]
WARNING: CPU: 6 PID: 1960 at /home/peter/src/kernels/mainline/kernel/sched/core.c:7286 __might_sleep+0x7f/0x90()
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8151805e>] paste_selection+0x9e/0x1a0
Modules linked in: btrfs xor raid6_pq ufs qnx4 hfsplus hfs minix ntfs msdos jfs xfs libcrc32c .....
CPU: 6 PID: 1960 Comm: gpm Not tainted 4.1.0-rc7+tty-xeon+debug #rc7+tty
Hardware name: Dell Inc. Precision WorkStation T5400 /0RW203, BIOS A11 04/30/2012
ffffffff81c9c0a0 ffff8802b0fd3ac8 ffffffff8185778a 0000000000000001
ffff8802b0fd3b18 ffff8802b0fd3b08 ffffffff8108039a ffffffff82ae8510
ffffffff81c9ce00 0000000000000015 0000000000000000 0000000000000000
Call Trace:
[<ffffffff8185778a>] dump_stack+0x4f/0x7b
[<ffffffff8108039a>] warn_slowpath_common+0x8a/0xc0
[<ffffffff81080416>] warn_slowpath_fmt+0x46/0x50
[<ffffffff810ddced>] ? __lock_acquire+0xe2d/0x13a0
[<ffffffff8151805e>] ? paste_selection+0x9e/0x1a0
[<ffffffff8151805e>] ? paste_selection+0x9e/0x1a0
[<ffffffff810ad4ff>] __might_sleep+0x7f/0x90
[<ffffffff8185f76a>] down_read+0x2a/0xa0
[<ffffffff810bb1d8>] ? sched_clock_cpu+0xb8/0xe0
[<ffffffff8150d1dc>] n_tty_receive_buf_common+0x4c/0xba0
[<ffffffff810dc875>] ? mark_held_locks+0x75/0xa0
[<ffffffff81861c95>] ? _raw_spin_unlock_irqrestore+0x65/0x80
[<ffffffff810b49a1>] ? get_parent_ip+0x11/0x50
[<ffffffff8150dd44>] n_tty_receive_buf2+0x14/0x20
[<ffffffff81518117>] paste_selection+0x157/0x1a0
[<ffffffff810b77b0>] ? wake_up_state+0x20/0x20
[<ffffffff815203f8>] tioclinux+0xb8/0x2c0
[<ffffffff81515bfe>] vt_ioctl+0xaee/0x11a0
[<ffffffff810baf75>] ? sched_clock_local+0x25/0x90
[<ffffffff810bbe11>] ? vtime_account_user+0x91/0xa0
[<ffffffff8150810c>] tty_ioctl+0x20c/0xe20
[<ffffffff810bbe11>] ? vtime_account_user+0x91/0xa0
[<ffffffff810b49a1>] ? get_parent_ip+0x11/0x50
[<ffffffff810b4a69>] ? preempt_count_sub+0x49/0x50
[<ffffffff811ab71c>] ? context_tracking_exit+0x5c/0x290
[<ffffffff811ab71c>] ? context_tracking_exit+0x5c/0x290
[<ffffffff81248b98>] do_vfs_ioctl+0x318/0x570
[<ffffffff810dca8d>] ? trace_hardirqs_on+0xd/0x10
[<ffffffff810dc9b5>] ? trace_hardirqs_on_caller+0x115/0x1e0
[<ffffffff81254acc>] ? __fget_light+0x6c/0xa0
[<ffffffff81248e71>] SyS_ioctl+0x81/0xa0
[<ffffffff81862832>] system_call_fastpath+0x16/0x7a
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Convert the tty_buffer_flush() exclusion mechanism to a
public interface - tty_buffer_lock/unlock_exclusive() - and use
the interface to safely write the paste selection to the line
discipline.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Although line discipline receiving is single-producer/single-consumer,
using tty->receive_room to manage flow control creates unnecessary
critical regions requiring additional lock use.
Instead, introduce the optional .receive_buf2() ldisc method which
returns the # of bytes actually received. Serialization is guaranteed
by the caller.
In turn, the line discipline should schedule the buffer work item
whenever space becomes available; ie., when there is room to receive
data and receive_room() previously returned 0 (the buffer work
item stops processing if receive_buf2() returns 0). Note the
'no room' state need not be atomic despite concurrent use by two
threads because only the buffer work thread can set the state and
only the read() thread can clear the state.
Add n_tty_receive_buf2() as the receive_buf2() method for N_TTY.
Provide a public helper function, tty_ldisc_receive_buf(), to use
when directly accessing the receive_buf() methods.
Line disciplines not using input flow control can continue to set
tty->receive_room to a fixed value and only provide the receive_buf()
method.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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There used to be a single tty_ldisc_ref_wait. But then, when a
big-tty-mutex (BTM) was introduced, it has to be tty_ldisc_ref +
tty_unlock + tty_ldisc_ref_wait + tty_lock. Later, BTM was removed
from that path and tty_ldisc_ref + tty_ldisc_ref_wait remained there.
But it makes no sense now. So leave there only tty_ldisc_ref_wait.
And when we have a reference to an ldisc, actually use it in the loop.
Otherwise it may be racy.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We leave the existing paste mess alone and just fix up the vt side of
things.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Some of this ventures into selection which is still a complete lost cause. We
are not making it any worse. It's completely busted anyway.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Keyboard struct lifetime is easy, but the locking is not and is completely
ignored by the existing code. Tackle this one head on
- Make the kbd_table private so we can run down all direct users
- Hoick the relevant ioctl handlers into the keyboard layer
- Lock them with the keyboard lock so they don't change mid keypress
- Add helpers for things like console stop/start so we isolate the poking
around properly
- Tweak the braille console so it still builds
There are a couple of FIXME locking cases left for ioctls that are so hideous
they should be addressed in a later patch. After this patch the kbd_table is
private and all the keyboard jiggery pokery is in one place.
This update fixes speakup and also a memory leak in the original.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We used it really only serial and ami_serial. The rest of the
callsites were BUG/WARN_ONs to check if BTM is held. Now that we
pruned tty_locked from both of the real users, we can get rid of
tty_lock along with __big_tty_mutex_owner.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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This reverts commit b1c43f82c5aa265442f82dba31ce985ebb7aa71c.
It was broken in so many ways, and results in random odd pty issues.
It re-introduced the buggy schedule_work() in flush_to_ldisc() that can
cause endless work-loops (see commit a5660b41af6a: "tty: fix endless
work loop when the buffer fills up").
It also used an "unsigned int" return value fo the ->receive_buf()
function, but then made multiple functions return a negative error code,
and didn't actually check for the error in the caller.
And it didn't actually work at all. BenH bisected down odd tty behavior
to it:
"It looks like the patch is causing some major malfunctions of the X
server for me, possibly related to PTYs. For example, cat'ing a
large file in a gnome terminal hangs the kernel for -minutes- in a
loop of what looks like flush_to_ldisc/workqueue code, (some ftrace
data in the quoted bits further down).
...
Some more data: It -looks- like what happens is that the
flush_to_ldisc work queue entry constantly re-queues itself (because
the PTY is full ?) and the workqueue thread will basically loop
forver calling it without ever scheduling, thus starving the consumer
process that could have emptied the PTY."
which is pretty much exactly the problem we fixed in a5660b41af6a.
Milton Miller pointed out the 'unsigned int' issue.
Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reported-by: Milton Miller <miltonm@bga.com>
Cc: Stefan Bigler <stefan.bigler@keymile.com>
Cc: Toby Gray <toby.gray@realvnc.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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it makes it simpler to keep track of the amount of
bytes received and simplifies how flush_to_ldisc counts
the remaining bytes. It also fixes a bug of lost bytes
on n_tty when flushing too many bytes via the USB
serial gadget driver.
Tested-by: Stefan Bigler <stefan.bigler@keymile.com>
Tested-by: Toby Gray <toby.gray@realvnc.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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remove invalid location line in each file header after location
moved from driver/char to driver/tty
Signed-off-by: Jovi Zhang <bookjovi@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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These were missed the last time I cleaned this up
globally, because of code moving around or new code
getting merged.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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The -rt patches change the console_semaphore to console_mutex. As a
result, a quite large chunk of the patches changes all
acquire/release_console_sem() to acquire/release_console_mutex()
This commit makes things use more neutral function names which dont make
implications about the underlying lock.
The only real change is the return value of console_trylock which is
inverted from try_acquire_console_sem()
This patch also paves the way to switching console_sem from a semaphore to
a mutex.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: make console_trylock return 1 on success, per Geert]
Signed-off-by: Torben Hohn <torbenh@gmx.de>
Cc: Thomas Gleixner <tglx@tglx.de>
Cc: Greg KH <gregkh@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The vt and other related code is moved into the drivers/tty/vt directory.
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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