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commit 6987dc8a70976561d22450b5858fc9767788cc1c upstream.
Only read access is checked before this call.
Actually, at the moment this is not an issue, as every in-tree arch does
the same manual checks for VERIFY_READ vs VERIFY_WRITE, relying on the MMU
to tell them apart, but this wasn't the case in the past and may happen
again on some odd arch in the future.
If anyone cares about 3.7 and earlier, this is a security hole (untested)
on real 80386 CPUs.
Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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When resizing a vt its selection may exceed the new size, resulting in
an invalid memory access [1]. Clear the selection before resizing.
[1] http://lkml.kernel.org/r/CACT4Y+acDTwy4umEvf5ROBGiRJNrxHN4Cn5szCXE5Jw-d1B=Xw@mail.gmail.com
Reported-and-tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Scot Doyle <lkml14@scotdoyle.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Size of kmalloc() in vc_do_resize() is controlled by user.
Too large kmalloc() size triggers WARNING message on console.
Put a reasonable upper bound on terminal size to prevent WARNINGs.
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
CC: David Rientjes <rientjes@google.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: linux-kernel@vger.kernel.org
Cc: syzkaller@googlegroups.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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In csi_J(3), the third parameter of scr_memsetw (vc_screenbuf_size) is
divided by 2 inappropriatelly. But scr_memsetw expects size, not
count, because it divides the size by 2 on its own before doing actual
memset-by-words.
So remove the bogus division.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Petr Písař <ppisar@redhat.com>
Fixes: f8df13e0a9 (tty: Clean console safely)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge my system logging cleanups, triggered by the broken '\n' patches.
The line continuation handling has been broken basically forever, and
the code to handle the system log records was both confusing and
dubious. And it would do entirely the wrong thing unless you always had
a terminating newline, partly because it couldn't actually see whether a
message was marked KERN_CONT or not (but partly because the LOG_CONT
handling in the recording code was rather confusing too).
This re-introduces a real semantically meaningful KERN_CONT, and fixes
the few places I noticed where it was missing. There are probably more
missing cases, since KERN_CONT hasn't actually had any semantic meaning
for at least four years (other than the checkpatch meaning of "no log
level necessary, this is a continuation line").
This also allows the combination of KERN_CONT and a log level. In that
case the log level will be ignored if the merging with a previous line
is successful, but if a new record is needed, that new record will now
get the right log level.
That also means that you can at least in theory combine KERN_CONT with
the "pr_info()" style helpers, although any use of pr_fmt() prefixing
would make that just result in a mess, of course (the prefix would end
up in the middle of a continuing line).
* printk-cleanups:
printk: make reading the kernel log flush pending lines
printk: re-organize log_output() to be more legible
printk: split out core logging code into helper function
printk: reinstate KERN_CONT for printing continuation lines
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Long long ago the kernel log buffer was a buffered stream of bytes, very
much like stdio in user space. It supported log levels by scanning the
stream and noticing the log level markers at the beginning of each line,
but if you wanted to print a partial line in multiple chunks, you just
did multiple printk() calls, and it just automatically worked.
Except when it didn't, and you had very confusing output when different
lines got all mixed up with each other. Then you got fragment lines
mixing with each other, or with non-fragment lines, because it was
traditionally impossible to tell whether a printk() call was a
continuation or not.
To at least help clarify the issue of continuation lines, we added a
KERN_CONT marker back in 2007 to mark continuation lines:
474925277671 ("printk: add KERN_CONT annotation").
That continuation marker was initially an empty string, and didn't
actuall make any semantic difference. But it at least made it possible
to annotate the source code, and have check-patch notice that a printk()
didn't need or want a log level marker, because it was a continuation of
a previous line.
To avoid the ambiguity between a continuation line that had that
KERN_CONT marker, and a printk with no level information at all, we then
in 2009 made KERN_CONT be a real log level marker which meant that we
could now reliably tell the difference between the two cases.
5fd29d6ccbc9 ("printk: clean up handling of log-levels and newlines")
and we could take advantage of that to make sure we didn't mix up
continuation lines with lines that just didn't have any loglevel at all.
Then, in 2012, the kernel log buffer was changed to be a "record" based
log, where each line was a record that has a loglevel and a timestamp.
You can see the beginning of that conversion in commits
e11fea92e13f ("kmsg: export printk records to the /dev/kmsg interface")
7ff9554bb578 ("printk: convert byte-buffer to variable-length record buffer")
with a number of follow-up commits to fix some painful fallout from that
conversion. Over all, it took a couple of months to sort out most of
it. But the upside was that you could have concurrent readers (and
writers) of the kernel log and not have lines with mixed output in them.
And one particular pain-point for the record-based kernel logging was
exactly the fragmentary lines that are generated in smaller chunks. In
order to still log them as one recrod, the continuation lines need to be
attached to the previous record properly.
However the explicit continuation record marker that is actually useful
for this exact case was actually removed in aroundm the same time by commit
61e99ab8e35a ("printk: remove the now unnecessary "C" annotation for KERN_CONT")
due to the incorrect belief that KERN_CONT wasn't meaningful. The
ambiguity between "is this a continuation line" or "is this a plain
printk with no log level information" was reintroduced, and in fact
became an even bigger pain point because there was now the whole
record-level merging of kernel messages going on.
This patch reinstates the KERN_CONT as a real non-empty string marker,
so that the ambiguity is fixed once again.
But it's not a plain revert of that original removal: in the four years
since we made KERN_CONT an empty string again, not only has the format
of the log level markers changed, we've also had some usage changes in
this area.
For example, some ACPI code seems to use KERN_CONT _together_ with a log
level, and now uses both the KERN_CONT marker and (for example) a
KERN_INFO marker to show that it's an informational continuation of a
line.
Which is actually not a bad idea - if the continuation line cannot be
attached to its predecessor, without the log level information we don't
know what log level to assign to it (and we traditionally just assigned
it the default loglevel). So having both a log level and the KERN_CONT
marker is not necessarily a bad idea, but it does mean that we need to
actually iterate over potentially multiple markers, rather than just a
single one.
Also, since KERN_CONT was still conceptually needed, and encouraged, but
didn't actually _do_ anything, we've also had the reverse problem:
rather than having too many annotations it has too few, and there is bit
rot with code that no longer marks the continuation lines with the
KERN_CONT marker.
So this patch not only re-instates the non-empty KERN_CONT marker, it
also fixes up the cases of bit-rot I noticed in my own logs.
There are probably other cases where KERN_CONT will be needed to be
added, either because it is new code that never dealt with the need for
KERN_CONT, or old code that has bitrotted without anybody noticing.
That said, we should strive to avoid the need for KERN_CONT. It does
result in real problems for logging, and should generally not be seen as
a good feature. If we some day can get rid of the feature entirely,
because nobody does any fragmented printk calls, that would be lovely.
But until that point, let's at mark the code that relies on the hacky
multi-fragment kernel printk's. Not only does it avoid the ambiguity,
it also annotates code as "maybe this would be good to fix some day".
(That said, particularly during single-threaded bootup, the downsides of
KERN_CONT are very limited. Things get much hairier when you have
multiple threads going on and user level reading and writing logs too).
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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For now, these fall back to regular (dark) colors.
It'd be tempting to replace blink with bright backgrounds, as permitted by
CGA/VGA -- we already muck with the other programmable bit (foreground
brightness vs 512 character font). This would bring vgacon in line with
fbcon, which doesn't support blink anywhere but on some drivers renders
that bit as bright background. If that is done, this commit should be
amended to be one of ways of setting that bit.
Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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These codes are supported by all major terminals, thus they occasionally see
some use despite being redundant with \e[38;5;(x+8)m or (less exactly)
\e[1;3(x)m.
Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Some guy went on a patching spree, adding 24-bit colour support all around:
https://gist.github.com/XVilka/8346728
Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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All other uses of vc_npar are inclusive (save for < NPAR) which raises
eyebrows, so let's at least do so consistently.
Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This makes it show up on UBSAN:
perl -e 'for (0..15) {my @x=("0")x$_;push @x,qw(38 2 64 128 192 4);printf
"\e[%smAfter %d zeroes.\e[0m\n", join(";",@x[0..($_+5<15?$_+5:15)]), $_}'
Seems harmless: if you can programmatically read attributes of a vt
character (/dev/vcsa*), multiple probes can obtain parts of vt_mode then
lowest byte (5th on 64-bit big-endian) of a pointer.
Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We want the tty/serial fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We are getting somewhat random soft lockups with this signature:
[ 86.992215] [<fffffc00080935e0>] el1_irq+0xa0/0x10c
[ 86.997082] [<fffffc000841822c>] cursor_timer_handler+0x30/0x54
[ 87.002991] [<fffffc000810ec44>] call_timer_fn+0x54/0x1a8
[ 87.008378] [<fffffc000810ef88>] run_timer_softirq+0x1c4/0x2bc
[ 87.014200] [<fffffc000809077c>] __do_softirq+0x114/0x344
[ 87.019590] [<fffffc00080af45c>] irq_exit+0x74/0x98
[ 87.024458] [<fffffc00080fac20>] __handle_domain_irq+0x98/0xfc
[ 87.030278] [<fffffc000809056c>] gic_handle_irq+0x94/0x190
This is caused by the vt visual_init() function calling into
fbcon_init() with a vc_cur_blink_ms value of zero. This is a
transient condition, as it is later set to a non-zero value. But, if
the timer happens to expire while the blink rate is zero, it goes into
an endless loop, and we get soft lockup.
The fix is to initialize vc_cur_blink_ms before calling the con_init()
function.
Signed-off-by: David Daney <david.daney@cavium.com>
Cc: stable@vger.kernel.org
Acked-by: Pavel Machek <pavel@ucw.cz>
Tested-by: Ming Lei <ming.lei@canonical.com>
Acked-by: Scot Doyle <lkml14@scotdoyle.com>
Tested-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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vc_deccolm is only set and never read, remove the member from vc_data.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Namely convert:
* IS_FG -> con_is_fg
* DO_UPDATE -> con_should_update
* CON_IS_VISIBLE -> con_is_visible
DO_UPDATE was a weird name for a yes/no answer, so the new name is
con_should_update.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Thomas Winischhofer <thomas@winischhofer.net>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: linux-usb@vger.kernel.org
Cc: linux-fbdev@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Flush the switch cases to be aligned with the switch. Mostly
everything can now fit to the 80-chars terminal.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Do not opencode max3, use the macro.
Separate commands. Until now, I have not noticed the comma. Make it
one line, one command. And make the code obvious.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The compiler noticed passing structure over stack. Even though rgb is
a small structure, let us define one and pass that over all the
functions wherever needed.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The code with T.416 high colors handling is flushed to the right and
hard to read. Move the code to a separate function and remove code
duplication for foreground & background colors.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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It's a macro accessing and changing some local variables. And the code
uses it without appending semicolon which confuses everybody too.
Switch from this bad guy to a sane standard function.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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It is never defined. And I spent quite some time looking into the
history and cannot find how this was ever used. Given it was not used
in the history, I doubt it currently works as expected after the years
of changes all over the code.
So kill it.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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* allow NULL consw->con_set_palette (some consoles define an empty
hook)
* => remove empty hooks now
* return value of consw->con_set_palette is never checked => make the
function void
* document consw->con_set_palette a bit
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Thomas Winischhofer <thomas@winischhofer.net>
Cc: linux-usb@vger.kernel.org
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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* allow NULL consw->con_scrolldelta (some consoles define an empty
hook)
* => remove empty hooks now
* return value of consw->con_scrolldelta is never checked => make the
function void
* document consw->con_scrolldelta a bit
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Thomas Winischhofer <thomas@winischhofer.net>
Cc: linux-usb@vger.kernel.org
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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It is always called with 0, so remove the parameter and pass the
default down to scrolldelta without checking.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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When the console is already registered, stop crawling the
registered_con_driver array and return an error immediatelly.
This makes the code more obvious. And we do not need to initialize
retval anymore.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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>
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Every user of default_red, default_grn, and default_blu treats them as
unsigned char. So make it really unsigned char.
And indent the initializers and module_param properly.
This saves ~ 100 bytes of data.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This means all ->con_set_palette have to have the second parameter
const too now.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Some code in vc_allocate is indented by 4 spaces. It is inside a
condition. Invert the condition and move the code to the first
indentation level (using \tab). And insert some empty lines to have
logical code blocks separated.
Then, instead of freeing in an 'if' false branch, use goto-error
label as fail path.
Maybe better to look at this patch with diff -w -b.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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MAX_NR_CONSOLES and MAX_NR_USER_CONSOLES are both 63 since they were
introduced in 1.1.54. And since vc_allocate does:
if (currcons >= MAX_NR_CONSOLES)
return -ENXIO;
if (!vc_cons[currcons].d) {
if (currcons >= MAX_NR_USER_CONSOLES && !capable(CAP_SYS_RESOURCE))
return -EPERM;
}
the second check is pointless. Remove both the check and the macro
MAX_NR_USER_CONSOLES.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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add_softcursor() stores the contents of the text buffer position in this
variable before drawing the softcursor, whereas hide_softcursor() writes
the value back. A value of -1 means that no cursor has been drawn and
therefore no character is to be restored. softcursor_original, however,
is only implicitly initialized with 0. Therefore, when hide_softcursor
is called for the first time (console_init -> con_init -> redraw_screen
-> hide_cursor), it wrongly writes 0x0000 in the top left corner of
the text buffer. Normally, this is just as black as the rest of the
screen (vc_video_erase_char) and can't be seen, but it appears as a
black cursor rectangle on non-black backgrounds e.g. with boot option
"vt.global_cursor_default=0 vt.color=0xf0". softcursor_original needs
to be initialized with -1.
Signed-off-by: Melchior FRANZ <mfranz@aon.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging
Pull staging fixes from Greg KH:
"Here are some small staging driver fixes for 4.5-rc2.
One of them predated 4.4-final, but I missed that merge window due to
the holliday. The others fix reported issues that have come up
recently. The tty change is needed for the speakup driver fix and has
the ack of the tty driver maintainer as well, i.e. myself :)
All have been in linux-next with no reported issues"
* tag 'staging-4.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
Staging: speakup: fix read scrolled-back VT
Staging: speakup: Fix getting port information
Revert "Staging: panel: usleep_range is preferred over udelay"
iio: adis_buffer: Fix out-of-bounds memory access
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Previously, speakup would always read the non-scrolled part of the VT,
even when the VT is scrolled back with shift-page. This patch makes
vt.c export screen_pos so that speakup can use it to properly access
the content of the scrolled-back VT.
This was tested with both vgacon and fbcon.
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This function compiles to 79 bytes of machine code.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
CC: Jiri Slaby <jslaby@suse.com>
CC: linux-serial@vger.kernel.org
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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If vc->vc_uni_pagedir_loc is not NULL, its refcount needs to be
decreased before vc_uni_pagedir_loc is re-assigned.
unreferenced object 0xffff88002cdd13b0 (size 512):
comm "setfont", pid 503, jiffies 4294896503 (age 722.828s)
hex dump (first 32 bytes):
40 92 61 2b 00 88 ff ff 00 00 00 00 00 00 00 00 @.a+............
00 00 00 00 00 00 00 00 a0 ad 61 2b 00 88 ff ff ..........a+....
backtrace:
[<ffffffff817b755e>] kmemleak_alloc+0x4e/0xb0
[<ffffffff811d4898>] kmem_cache_alloc_trace+0x1c8/0x240
[<ffffffff814ae7d3>] con_do_clear_unimap.isra.2+0x83/0xe0
[<ffffffff814ae9b2>] con_clear_unimap+0x22/0x40
[<ffffffff814a8db8>] vt_ioctl+0xeb8/0x1170
[<ffffffff8149b458>] tty_ioctl+0x208/0xca0
[<ffffffff81207858>] do_vfs_ioctl+0x2f8/0x510
[<ffffffff81207af1>] SyS_ioctl+0x81/0xa0
[<ffffffff817ca2b2>] system_call_fastpath+0x16/0x75
[<ffffffffffffffff>] 0xffffffffffffffff
unreferenced object 0xffff88002b619240 (size 256):
comm "setfont", pid 503, jiffies 4294896503 (age 722.828s)
hex dump (first 32 bytes):
90 bc 84 d5 00 88 ff ff 58 85 84 d5 00 88 ff ff ........X.......
88 ac 84 d5 00 88 ff ff e0 b1 84 d5 00 88 ff ff ................
backtrace:
[<ffffffff817b755e>] kmemleak_alloc+0x4e/0xb0
[<ffffffff811d4898>] kmem_cache_alloc_trace+0x1c8/0x240
[<ffffffff814ae286>] con_insert_unipair+0x86/0x170
[<ffffffff814af107>] con_set_unimap+0x1b7/0x280
[<ffffffff814a8d65>] vt_ioctl+0xe65/0x1170
[<ffffffff8149b458>] tty_ioctl+0x208/0xca0
[<ffffffff81207858>] do_vfs_ioctl+0x2f8/0x510
[<ffffffff81207af1>] SyS_ioctl+0x81/0xa0
[<ffffffff817ca2b2>] system_call_fastpath+0x16/0x75
[<ffffffffffffffff>] 0xffffffffffffffff
Signed-off-by: Dongxing Zhang <dongxing.zhang@intel.com>
Signed-off-by: Xiaoming Wang <xiaoming.wang@intel.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Tested-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This was introduced in
commit 6db4063c5b72b46e9793b0f141a7a3984ac6facf
Author: Antonino A. Daplas <adaplas@gmail.com>
Date: Mon Jun 26 00:27:12 2006 -0700
[PATCH] VT binding: Add sysfs control to the VT layer
with the justification
"In addition, if any of the consoles are in KD_GRAPHICS mode, binding and
unbinding will not succeed. KD_GRAPHICS mode usually indicates that the
underlying console hardware is used for other purposes other than displaying
text (ie X). This feature should prevent binding/unbinding from interfering
with a graphics application using the VT."
I think we should lift this artificial restriction though:
- KD_GRAPHICS doesn't get cleaned up automatically, which means it's
easy to have terminals stuck in KD_GRAPHICS when hacking around on
X.
- X doesn't really care, especially with drm where kms already blocks
fbdev (and hence fbcon) when there's an active compositor.
- This is a root-only interface with a separate .config option and
it's possible to hang your machine already anyway if you
unload/reload drivers and don't know what you're doing.
With this patch i915.ko module reloading works again reliably,
something in the recent fedora upgrades broke things.
Cc: Antonino A. Daplas <adaplas@gmail.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Acked-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Currently there is a lock order problem between the console lock and the
kernfs s_active lock of the console driver's bind sysfs entry. When
writing to the sysfs entry the lock order is first s_active then console
lock, when unregistering the console driver via
do_unregister_con_driver() the order is the opposite. See the below
bugzilla reference for one instance of a lockdep backtrace.
Fix this by unregistering the console driver from a deferred work, where
we can safely drop the console lock while unregistering the device and
corresponding sysfs entries (which in turn acquire s_active). Note that
we have to keep the console driver slot in the registered_con_driver
array reserved for the driver that's being unregistered until it's fully
removed. Otherwise a concurrent call to do_register_con_driver could
try to reuse the same slot and fail when registering the corresponding
device with a minor index that's still in use.
Note that the referenced bug report contains two dmesg logs with two
distinct lockdep reports: [1] is about a locking scenario involving
s_active, console_lock and the fb_notifier list lock, while [2] is
about a locking scenario involving only s_active and console_lock.
In [1] locking fb_notifier triggers the lockdep warning only because
of its dependence on console_lock, otherwise case [1] is the same
s_active<->console_lock dependency problem fixed by this patch.
Before this change we have the following locking scenarios involving
the 3 locks:
a) via do_unregister_framebuffer()->...->do_unregister_con_driver():
1. console lock 2. fb_notifier lock 3. s_active lock
b) for example via give_up_console()->do_unregister_con_driver():
1. console lock 2. s_active lock
c) via vt_bind()/vt_unbind():
1. s_active lock 2. console lock
Since c) is the console bind sysfs entry's write code path we can't
change the locking order there. We can only fix this issue by removing
s_active's dependence on the other two locks in a) and b). We can do
this only in the vt code which owns the corresponding sysfs entry, so
that after the change we have:
a) 1. console lock 2. fb_notifier lock
b) 1. console lock
c) 1. s_active lock 2. console lock
d) in the new con_driver_unregister_callback():
1. s_active lock
[1] https://bugs.freedesktop.org/attachment.cgi?id=87716
[2] https://bugs.freedesktop.org/attachment.cgi?id=107602
v2:
- get console_lock earlier in con_driver_unregister_callback(), so we
protect the following console driver field assignments there
- add code coment explaining the reason for deferring the sysfs entry
removal
- add a third paragraph to the commit message explaining why there are
two distinct lockdep reports and that this issue is independent of
fb/fbcon. (Peter Hurley)
v3:
- clarify further the third paragraph
v4:
- rebased on v4 of patch 1/3
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add an escape sequence to specify the current console's cursor blink
interval. The interval is specified as a number of milliseconds until
the next cursor display state toggle, from 50 to 65535. /proc/loadavg
did not show a difference with a one msec interval, but the lower
bound is set to 50 msecs since slower hardware wasn't tested.
Store the interval in the vc_data structure for later access by fbcon,
initializing the value to fbcon's current hardcoded value of 200 msecs.
Signed-off-by: Scot Doyle <lkml14@scotdoyle.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Instead of manual calls of device_create_file() and
device_remove_file(), pass the static attribute groups using
device_create_with_groups().
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Converting milliseconds to jiffies by "val * HZ / 1000" is technically
OK but msecs_to_jiffies(val) is the cleaner solution and handles all
corner cases correctly. This is a minor API consolidation only and
should make things more readable.
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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this patch fixes following sparse warning:
vt.c:1240:12: warning: symbol 'rgb_from_256' was not declared. Should it be static?
Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Currently vt_bind and vt_unbind access at least the con_driver object
and registered_con_driver array without holding the console lock. Fix
this by locking around the whole function in each case.
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The default console driver (conswitchp) and busy drivers bound to a
console (as reported by con_is_bound()) shouldn't be unregistered.
System console drivers (without the CON_DRIVER_FLAG_MODULE flag) can be
unregistered, provided they are neither default nor busy. The current
code checks for the CON_DRIVER_FLAG_INIT flag but this doesn't make
sense: this flag is set for a driver whenever its associated console's
con_startup() function is called, which first happens when the console
driver is registered (so before the console gets bound) and gets cleared
when the console gets unbound. The purpose of this flag is to show if we
need to call con_startup() on a console before we use it.
Based on the above, do_unregister_con_driver() in its current form will
allow unregistering a console driver only if it was never bound, but
will refuse to unregister one that was bound and later unbound.
Fix this by dropping the CON_DRIVER_FLAG_INIT check, allowing
unregistering of any console driver provided that it's not the default
one and it's not busy.
v2:
- reword the third paragraph to clarify how the fix works (Peter Hurley)
v3:
- unchanged
v4:
- Allow unregistering a system console driver too, needed by i915 to
unregister vgacon. Update commit description accordingly. (Daniel)
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Convert the pr_warning to the more common pr_warn.
Other miscellanea:
o Convert unusual PR_FMT define and uses to pr_fmt
o Remove unnecessary OOM message
o Fix grammar in an error message
o Convert a pr_warning with a KERN_ERR to pr_err
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Commit 68952076e9226cc23ebce66d3fc2fdb8b6c04c30 ("vt: Remove
vt_get_kmsg_redirect() from uapi header") fails to compile if
!CONFIG_VT_CONSOLE.
Move macro definition for vt_get_kmsg_redirect() up with file-scope
function declarations.
Reported-by: Jim Davis <jim.epost@gmail.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch fixes sparse warning:
"obsolete struct initializer, use C99 syntax"
Signed-off-by: Peng Fan <van.freenix@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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vt_get_kmsg_redirect() only has meaning to the console driver as
an alias for calling vt_kmsg_redirect(). Move the macro definition
to the only source file which uses it; remove from uapi/linux/vt.h
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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git://anongit.freedesktop.org/drm-intel into drm-next
First round of fixes for 3.16-rc, mostly cc: stable, and the vt/vgacon
fixes from Daniel [1] to avoid hangs and unclaimed register errors on
module load/reload.
* tag 'drm-intel-fixes-2014-06-17' of git://anongit.freedesktop.org/drm-intel:
drm/i915/bdw: remove erroneous chv specific workarounds from bdw code
drm/i915: fix possible refcount leak when resetting forcewake
drm/i915: Reorder semaphore deadlock check
drm/i95: Initialize active ring->pid to -1
drm/i915: set backlight duty cycle after backlight enable for gen4
drm/i915: Avoid div-by-zero when pixel_multiplier is zero
drm/i915: Disable FBC by default also on Haswell and later
drm/i915: Kick out vga console
drm/i915: Fixup global gtt cleanup
vt: Don't ignore unbind errors in vt_unbind
vt: Fix up unregistration of vt drivers
vt: Fix replacement console check when unbinding
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Otherwise the loop will never stop since we don't make any
forward progress. Noticed while breaking this accidentally
in a painful attempt to make vga_con unregistering work.
With this patch we'll bail out on the first attempt, which
at least leaves a useful enough system behind for debugging.
Livelocks on console_lock just aren't fun.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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